Sound Practices Mailing List Files - Volume 2
=========================================================================
From: "Norman Tracy" <ntracy@galstar.com>
Subject: [JN] IAG Terminal boards = The Good Stuff
Date: Tue, 31 Oct 2000 14:18:40 -0600
Source: Sound Digest Archive v02.n714
'Yo Joes!
I have discovered a product you NEED to be using whenever it is time to
build that next tube project. I had been seeing ads in Glass Audio for
terminal boards by a company called IAG or International Audio Group.
Pictures looked nice so when I wanted to do tube circuit prototyping I
ordered some to save time mounting sockets and junk box terminals on the
breadboard. The quality of what arrived greatly exceeded my expectations.
Features:
- - ceramic sockets with gold contacts
- - sockets already mounted to board
- - board is 1/8" (3mm) thick with copper ground plane on one side
- - beefy terminals correctly staked to PCB
- - complete set of mounting screws and stand-offs
- - paper template to locate holes for mounting screws and tube holes in
chassis
- - even the edges of board are sanded smooth!
The fit and finish is just outstanding. It is no wonder IAG's customers
include some of the top amp builders in Japan. The sockets are exactly
centered in their holes. The terminals in perfect straight lines. All holes
are obviously CNC drilled during PCB fab. I know the terminals are correctly
staked because one of mine got bent in shipping. When I straightened it back
up there was NO play or loosening. Let me explain why this is important and
I find it impressive. Staking terminals to a PCB is like using rivets. Do it
right and they stay together for 50 years, do it wrong and the first stress
yields failure. The terminal is inserted in a hole, backed up with a anvil
then struck with a tool or press. The hole needs to be exactly the correct
size, the tooling correct for the terminal being mounted, the operator
trained and experienced. IAG has its act together on all these counts.
All in all pretty damn impressive for under $10 for a single socket or under
$20 for a dual. I know I could not even source the parts for that. He has
mini-9, octals, power tube and triode sockets all available. IAG also sells
terminal strips with just a row of terminals for CHEAP with the same
quality. Also your custom requests are no problem.
Customer service is outstanding. My order totaled only $57 for 8 pieces and
Horace called me to check it arrived and to be sure I was happy.
Outstanding.
Finally IAG has a tube amp kit using triode wired EL84s called the 4.5SE. I
have not heard or seen it but again am struck by the high parts quality to
price ratio. Goodies like toroidal power and Sowter output trannies on a
hand polished deep drawn aluminum chassis for circa $600?!?!?! Check it out
at:
http://www.tubebuilder.com/EL84SE.html
IAG's web site is not up yet, Horace can e-mail details of his products.
Contact info:
Horace Atkinson
International Audio Group
PO Box 10096
Killeen, TX 76547-0096
hiag@mail.n-link.com
Happy Listening
Norman Tracy
Audio Crafters Guild
5102 E 38 PL
Tulsa OK 74135 USA
918.627.5878 voice
918.481.0970 fax
ntracy@galstar.com e-mail
www.galstar.com/~ntracy/acg URL
=========================================================================
From: "Ellen Oler" <ellenoler@earthlink.net>
Subject: re: [JN] IAG Terminal boards = The Good Stuff
Date: Tue, 31 Oct 2000 20:50:48 -0500
Source: Sound Digest Archive v02.n715
What Norman said.
Horace is a superstar craftsman and every one of us should be ecstatic
customers of his. Allen, you like the way Tek scopes are built? OEM some
stuff from Horace. The dude rocks and at a price that beats the dumpster.
And he is extremely customer-service oriented, as in phone calls, faxes back
and forth, emails, you name it, he'll answer it.
That contact info once again:
Horace Atkinson
International Audio Group
PO Box 10096
Killeen, TX 76547-0096
hiag@mail.n-link.com
- -j
=========================================================================
From: "schiff.chu" <schiff.chu@mciworld.com>
Subject: [JN] I am back
Date: Thu, 30 Sep 1999 12:39:32 -0600
Source: Sound Digest Archive v02.n290
Hi Joes,
Finally, I am in Seattle and got my own e-mail up. It is good to be back.
Now I just need to get hold of other Joes at Seattle.
hopper
=========================================================================
From: "=?ISO-8859-1?Q?Torbj=F8rn_Lien?=" <mdrivekl@online.no>
Subject: [JN] Ian Hunter?
Date: Sat, 15 Jan 2000 17:18:09 +0100
Source: Sound Digest Archive v02.n404
Yo all...
The other day at work, listening to the radio with just half an ear
(there was this program with various semi-old poptunes) I got just
alittle more conscious about one song by ( I think? ) Ian Hunter .
Nothing overly geniously or brilliant I'd say, but a nice quality
poptune anyway. Judged by the refrain, I'd expect the title to
be something like: "Be somebody, sometime."
The instrumentation and arrangement of the song was also
nothing special,-( judged through the really bad x-istor
portable in the office,-), but surprice surprice: At the very end
of the song, at last beat, this bass-flageolet-chord cuts through.
Completely unexpected, somewhat impropriate, but fun non the
less and I wonder....
This was Pastorius, right? Or? (Sounded just like him anyway.)
Do anybody on the list recognize this record/album?
(Title, year, record-label etc.)
Is it something worth the investment?
Is Pastorius taking (bass)part of whole album?
Regards
Torbjoern, Norway
>
>
>
>
=========================================================================
From: TubeGarden@aol.com
Subject: [JN] IBID 300B
Date: Wed, 28 Feb 2001 20:58:43 EST
Source: Sound Digest Archive v02.n821
- --part1_70.83f4dd7.27cf06d3_boundary
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Greets!
After a week, 24/7, of playing, the no R no C 300B SE is starting to get
really pretty good.
I added an ElectraPrint 100mA 50H audio choke on top of the 1:1 3631 coupling
transformer anode load for the EL84 to get a little more oomph.
Any more oomph and I die :)
Happy Ears!
Al B^}
How it is done:
3:1 input (90K:10K) transformer
EL84 wired triode using a 6AS7G wired diode (G to P) on the cathode
double decker coupling xformer/choke
300B using triple stack of 6X5 diodes on cathodes
ubt-2 output SE
- --part1_70.83f4dd7.27cf06d3_boundary
Content-Type: text/html; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
<HTML><FONT FACE=arial,helvetica><BODY BGCOLOR="#ffffff"><FONT SIZE=2>Greets!
<BR>
<BR>After a week, 24/7, of playing, the no R no C 300B SE is starting to get
<BR>really pretty good.
<BR>
<BR>I added an ElectraPrint 100mA 50H audio choke on top of the 1:1 3631 coupling
<BR>transformer anode load for the EL84 to get a little more oomph.
<BR>
<BR>Any more oomph and I die :)
<BR>
<BR>Happy Ears!
<BR>Al B^}
<BR>
<BR>
<BR>
<BR>
<BR>How it is done:
<BR>
<BR>3:1 input (90K:10K) transformer
<BR>
<BR>EL84 wired triode using a 6AS7G wired diode (G to P) on the cathode
<BR>
<BR>double decker coupling xformer/choke
<BR>
<BR>300B using triple stack of 6X5 diodes on cathodes
<BR>
<BR>ubt-2 output SE
<BR>
<BR></FONT></HTML>
- --part1_70.83f4dd7.27cf06d3_boundary--
=========================================================================
From: Carter Hendricks <carterh@crl.com>
Subject: [JN] I build the Earmax Clone [1996!]
Date: Sun, 24 Jan 1999 13:53:02 -0600
Source: Sound Digest Archive v02.n010
>
>>Date: Thu, 4 Apr 1996 12:01:47 -0500 (EST)
>>Message-Id: <199604041701.MAA23932@mimas.ctr.columbia.edu>
>>From: "Johannes S. Chiu" <jschiu@ctr.columbia.edu>
>>To: sound@mail.tpoint.net
>>Subject: I build the Earmax Clone
>>
>>For those of you who missed the thread, let me first summarize:
>>A few months ago, Lance posted a circuit that was kind of
>>reversed engineered from the earmax headphone amplifier. Other
>>than using three tubes and maybe having similar circuits, there
>>wasn't too much resemblance to the earmax. After the circuits was
>>posted, posts immediately appeared urging people to try out this
>>simple circuit and report to others the result. Many moons passed.
>>People posted again asking if anyone tried it. More silence.
>>
>>When I saw the circuit, I saw it as a perfect mini project for the
>>vacant time between the big ones. So, I gathered parts as a side thing.
>>To me, this project was a perfect exercise to try and build something
>>really small and compact. Last weekend, I was finally in the mood to
>>do it. The chassis took me about a day and the wiring another day or so.
>>
>>Ok, first questions first. How does it sound? Actually, I am quite
>>impressed. Personally, I have built two headphone amps in the past.
>>One was a straight buffer using the LT1010, the other was a monster
>>6AS7G cathode follower driven by a 6DJ8 diff amp. This one stands out
>>from both of them. Maybe because of the higher gain of this circuit, it
>>feels to have more punch and wallop. It's like moving from a cathode
>>follower pre-amp to a mu-follower, or like adding a huge cap to your
>>pre-amp power supply. Everything gets bigger. Unfortunately, this is
>>also it's biggest caveat. I could imagine some people hating it the
>>same way they hate the mu-follower or using big power supply caps.
>>But there is one thing I am certain nobody would deny if they listened
>>to it, and that is: the amp is really fun to listen to. It may disappoint
>>people in some areas, but certainly surprise them in other areas.
>>So, if you build it, which I wholeheartily recommend, just keep in mind
>>this is no Melos killer or Grado terminator, and if you set out to build
>>the ultimate headphone amp killer, you are better off running it off you
>>2A3 amp, with all the silver wiring and whole she-bang, or wait for Mike
>>to wind that perfect IT.
>>
>>Also, let me clarify a few things I did that was not in the diagrams.
>>First, gotta have those 100 Ohms grid stop resistors at the input tubes.
>>Second, looking through the earmax specs, it says it is powered by 18.9
>>VAC. This is what I did as well. I got a 19VAC 840 mA adaptor that plugs in
>>the power plug, and fed that to 3 of the 6DJ8s filament connected in series.
>>This 19 VAC also feeds a 10V filament transformer in reverse, to step up
>>to the needed 220VAC. I believe this is the optimum arrangement to keep
>>everything simple and compact. The chassis is shaped like a trapezoidal
>>column 6.5 inches long. The trapedzoid has a 2 and 4 inch top and bottom,
>>and is 2 inches high as well. This gives a volume that is roughly 1.5
>>times higher than the earmax. I believe the reason why the earmax is
>>more compact is because the tubes used either do not require higher
>>voltages than 40 V, or is has a smaller step up trans. I tried to use
>>a smaller trans., but the fact is that most small filament transformers
>>were not designed with efficiency in mind. So I had to pick one with
>>roughly double the VA rating than needed. Finally, I wanted it to drive
>>the low imp. headphones as well, so I got the tiny transistor type
transfromers
>>from Antique Elec. Supply (PT-K13 I believe). This is a tiny imp. transformer
>>from 1K5 to 60/60 Ohms. To save space, I used one of those Radio Shack 100K
>>volume pots. As you all can see, this is not a perfect design in terms of
>>sonics, so my words are definetely not the last as far as how it could sound.
>>
>>I tried the direct output with my Sennheiser HD420 phones. I also
>>managed to borrow a Grado SR-60 to try out the transformer coupled output.
>>I think the transformer will give you 90% of what is there. Maybe the
>>bass is a tad weaker, the highs are different, but still better than
>>straight out from those personal walkman or cd players. I certainly don't
>>care that much when I listen through headphones. I think people
>>are sometimes too obsessed about needing massive transformers. At a
>>few tens mW, these are just fine.
>>
>>Finally, if you could just see the unit, I think people would jump at
>>building this. I know there may be a few more details I didn't describe,
>>if there is overwhelming demand, I suppose I could clarify further.
>>
>>Now back to the regularly scheduled programming ...
>>
>>
>>--
>>Johannes S. Chiu
>>jschiu@ctr.columbia.edu
>>Columbia University
>>New York City
>>
>>
>>
>
>
>
=========================================================================
From: "Michael B. Hathaway" <triode@t-three.com>
Subject: Re: [JN] I built a tiny SE amp I like
Date: Wed, 11 Aug 1999 22:57:14 -0700
Source: Sound Digest Archive v02.n239
Rick:
You could also be running into the cathode bias limits that many of us have
seen with the 417's. I'd poke around with a scope probe to see if you can
determine where the clipping is coming from.
Mike
- ----- Original Message -----
From: Rick Francis <rfrancis@glasscity.net>
To: <sound@deliverator.io.com>
Sent: Wednesday, August 11, 1999 10:34 PM
Subject: [JN] I built a tiny SE amp I like
> Yup, I quit typing/barking and built something. It's a darn cute lil'
> parallel feed stereo 417A amplifier. I had the tubes, these OPTs that
> can't handle DC, and a loaner pair of Mikey's 50H 40ma chokes. (Thanks
> to Paul Joppa for suggesting this use for these OPTs!) And I'm waiting
> for some parts for a SE 2A3 amp w/ FS-030s, so wanted to build
> something.
>
> It's almost exactly the plan Lucas Cant has on the web -- version 2,
> with 2v lead-acid batteries for bias. (These are not found just
> anywhere, but I called around and found them locally for about $6.50
> each.)
>
> After finding how much signal they needed from the preamp (lots), I got
> this idea... I found I could plug the CD player (Stan Warren modded)
> straight into the amp, without even a volume control, and the actual
> volume was pretty right. So between the stanplayer and the speakers is a
> single tube, a cap, and the OPT with no DC.
>
> I *like* it. I liked it enough to drill and punch a matching stainless
> steel mini-chassis for the PS, which I hope to finish up this weekend.
> There's a very slight tizziness that makes me want to try some other
> blocking caps, but on the whole it is very good at a lot of things.
>
> But of course it is flea-power, and my speakers are impedance-friendly
> but no more than 91 db (Harmonic Precision Echelons). So I got to
> wondering how hard it would be to use the 417As as drivers for maybe
> 2A3s. Someone must have used this tube as a driver, but I can't recall
> where. Any tips greatly appreciated.
>
> Rick Francis
>
>
=========================================================================
From: Rick Francis <rfrancis@glasscity.net>
Subject: [JN] I built a tiny SE amp I like
Date: Thu, 12 Aug 1999 01:34:50 -0400
Source: Sound Digest Archive v02.n239
Yup, I quit typing/barking and built something. It's a darn cute lil'
parallel feed stereo 417A amplifier. I had the tubes, these OPTs that
can't handle DC, and a loaner pair of Mikey's 50H 40ma chokes. (Thanks
to Paul Joppa for suggesting this use for these OPTs!) And I'm waiting
for some parts for a SE 2A3 amp w/ FS-030s, so wanted to build
something.
It's almost exactly the plan Lucas Cant has on the web -- version 2,
with 2v lead-acid batteries for bias. (These are not found just
anywhere, but I called around and found them locally for about $6.50
each.)
After finding how much signal they needed from the preamp (lots), I got
this idea... I found I could plug the CD player (Stan Warren modded)
straight into the amp, without even a volume control, and the actual
volume was pretty right. So between the stanplayer and the speakers is a
single tube, a cap, and the OPT with no DC.
I *like* it. I liked it enough to drill and punch a matching stainless
steel mini-chassis for the PS, which I hope to finish up this weekend.
There's a very slight tizziness that makes me want to try some other
blocking caps, but on the whole it is very good at a lot of things.
But of course it is flea-power, and my speakers are impedance-friendly
but no more than 91 db (Harmonic Precision Echelons). So I got to
wondering how hard it would be to use the 417As as drivers for maybe
2A3s. Someone must have used this tube as a driver, but I can't recall
where. Any tips greatly appreciated.
Rick Francis
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: [JN] I can let you in on something new now.
Date: Fri, 07 May 1999 21:47:14 -0500
Source: Sound Digest Archive v02.n138
Hi All
A couple weeks ago I had mentioned a "New" loudspeaker design and said I
would tell more about it after the patent was filed. A bunch of people have
written, It is now filed and the NSCA show is over and the "dust" is
beginning to settle.
The system can be seen at http://servodrive.com/pages/unity.shtml
Several have asked about the rotary line source drivers like the type at the
last 2 BBQ's and those will be a product eventually but not now. I can
build the drivers on my coffee table but producing them (considering there
is no existing tooling for any of the parts) is a bigger job than we could
take on.
Around December I went to work for Brad at Servodrive (I was working for
ITC) and at the Christmas party he was teasing me about my trip to Egypt to
measure the Pyramid and said "hey can't you make a speaker out of a Pyramid"
and I said something like" yeah and it will sharpen your razor blades too".
Actually though I started thing about conical waveguides which also happened
to shaped like a Pyramid and one thing lead to another.
It is a new horn configuration which has never been employed (according to
a patent search and memory) and it allows one to do some really cool things.
A conical wave guide, while having more or less constant directivity and few
internal reflections, does not load well to low frequencies, generally
limiting them to hf use. One can see why when you look at the flare rate at
various points along the horn. It has a flare rate which starts high and
ends low, since the driver is at the small end and each section acts like a
high pass filter, the low frequency loading produced by the slower portion
is not felt by the driver.
The idea was to cut the horn into several parts and treat each part
according to its flare rate.
Drivers are chosen to match the horns acoustic impedance for these various
frequency ranges and front and rear volumes sized accordingly. At this point
you have a 3 way horn system, 3 separate horns.
Now, recombine the horn sections back into a single horn with the hf
driver(s) at the rear.
Through holes in the walls of the horn, the mid and low drivers are coupled
to the horn (at the correct acoustic impedance still) and the crossover
frequency (s) is chosen so that the difference in acoustic phase between the
higher and lower range is roughly equal to the phase of the crossover
network thus putting them in correct "time". As you can imagine, the
drivers are "acoustically very close" acoustic coupling between drivers and
ranges is very large and there is essentially NO interference between the
high/low sections. Because the hf driver is crossed over high and has a
fast flare rate and that the mid section has a large area/lower spl, throat
distortion is dramatically reduced for a given SPL
The "Unity" VFL speaker is of this design, it is a 22 1/2 inch cube and has
13 drivers, 8, 6 1/2" low frequency drivers 4, 4" compression loaded cone
drivers and a 1" compression driver. These are loaded in 60 degree square
waveguide. The pattern is constant across the 60 angle down to 400 HZ, by
200 HZ it is about 120 deg and so the reduction of room reflections provides
a very good stereo feel. The horn actually loads the mid drivers down to
about 250 HZ . TEF measurements are excelent.
The result is a horn system which has vastly less distortion and similarly
greater acoustic output than anything else of similar size. Sensitivity
(set by the woofer section) 102 dB 1 w 1m from 80 HZ to over 20 kHz + - 2 dB
and at 15 watts (~114dB@1m) is around 1/4 to 1/2 % THD, from 200 HZ
climbing to 1% at 2 K. Power handling is not a concern for Hi Fi
applications, in my house as loud as I would ever play them (which can be
pretty loud) requires peaks of 50 Watts ea and at that they are walking all
over my lonely Contrabass. (rated 800 Watts program)
Subjectively they are the most dynamic loudspeaker I have ever heard, lack
of room crap makes the stereo image very real and big. They are VERY clear .
Those of you that know me know I don't get worked up about something easily.
I haven't figured out when this years Chi Area HiFI BBQ will be yet,
probably in the Fall but they will be there then if you want to look with a
calibrated eye.
Tom Danley
ServoDrive
The thing about patents is that you can't build and sell a patented idea
(legally) but you can build things for you self.
=========================================================================
From: "Bill Gaw" <whg@tiac.net>
Subject: Re: [JN] I can let you in on something new now.
Date: Fri, 7 May 1999 22:27:22 -0400
Source: Sound Digest Archive v02.n138
Sounds like you've come up with another winner Tom. Couldyou tell us what
the list will be for these, and whether there'll be a kit for the home
builders to try? Is there some place in New England to listen to it? What do
you use for 80 hz. down- the contrabass or something else, and how do these
two mate. Thanks. Bill.
- ----- Original Message -----
From: Thomas Danley <Tom@ppci.com>
To: <sound@lists.io.com>
Cc: <bass@mcfeeley.cc.utexas.edu>
Sent: Friday, May 07, 1999 10:47 PM
Subject: [JN] I can let you in on something new now.
> Hi All
>
> A couple weeks ago I had mentioned a "New" loudspeaker design and said I
> would tell more about it after the patent was filed. A bunch of people
have
> written, It is now filed and the NSCA show is over and the "dust" is
> beginning to settle.
> The system can be seen at http://servodrive.com/pages/unity.shtml
>
> Several have asked about the rotary line source drivers like the type at
the
> last 2 BBQ's and those will be a product eventually but not now. I can
> build the drivers on my coffee table but producing them (considering there
> is no existing tooling for any of the parts) is a bigger job than we could
> take on.
> Around December I went to work for Brad at Servodrive (I was working for
> ITC) and at the Christmas party he was teasing me about my trip to Egypt
to
> measure the Pyramid and said "hey can't you make a speaker out of a
Pyramid"
> and I said something like" yeah and it will sharpen your razor blades
too".
> Actually though I started thing about conical waveguides which also
happened
> to shaped like a Pyramid and one thing lead to another.
>
> It is a new horn configuration which has never been employed (according
to
> a patent search and memory) and it allows one to do some really cool
things.
>
> A conical wave guide, while having more or less constant directivity and
few
> internal reflections, does not load well to low frequencies, generally
> limiting them to hf use. One can see why when you look at the flare rate
at
> various points along the horn. It has a flare rate which starts high and
> ends low, since the driver is at the small end and each section acts like
a
> high pass filter, the low frequency loading produced by the slower portion
> is not felt by the driver.
> The idea was to cut the horn into several parts and treat each part
> according to its flare rate.
> Drivers are chosen to match the horns acoustic impedance for these various
> frequency ranges and front and rear volumes sized accordingly. At this
point
> you have a 3 way horn system, 3 separate horns.
> Now, recombine the horn sections back into a single horn with the hf
> driver(s) at the rear.
> Through holes in the walls of the horn, the mid and low drivers are
coupled
> to the horn (at the correct acoustic impedance still) and the crossover
> frequency (s) is chosen so that the difference in acoustic phase between
the
> higher and lower range is roughly equal to the phase of the crossover
> network thus putting them in correct "time". As you can imagine, the
> drivers are "acoustically very close" acoustic coupling between drivers
and
> ranges is very large and there is essentially NO interference between the
> high/low sections. Because the hf driver is crossed over high and has a
> fast flare rate and that the mid section has a large area/lower spl,
throat
> distortion is dramatically reduced for a given SPL
>
> The "Unity" VFL speaker is of this design, it is a 22 1/2 inch cube and
has
> 13 drivers, 8, 6 1/2" low frequency drivers 4, 4" compression loaded
cone
> drivers and a 1" compression driver. These are loaded in 60 degree square
> waveguide. The pattern is constant across the 60 angle down to 400 HZ,
by
> 200 HZ it is about 120 deg and so the reduction of room reflections
provides
> a very good stereo feel. The horn actually loads the mid drivers down to
> about 250 HZ . TEF measurements are excelent.
> The result is a horn system which has vastly less distortion and similarly
> greater acoustic output than anything else of similar size. Sensitivity
> (set by the woofer section) 102 dB 1 w 1m from 80 HZ to over 20 kHz + - 2
dB
> and at 15 watts (~114dB@1m) is around 1/4 to 1/2 % THD, from 200 HZ
> climbing to 1% at 2 K. Power handling is not a concern for Hi Fi
> applications, in my house as loud as I would ever play them (which can be
> pretty loud) requires peaks of 50 Watts ea and at that they are walking
all
> over my lonely Contrabass. (rated 800 Watts program)
> Subjectively they are the most dynamic loudspeaker I have ever heard, lack
> of room crap makes the stereo image very real and big. They are VERY clear
.
>
> Those of you that know me know I don't get worked up about something
easily.
>
> I haven't figured out when this years Chi Area HiFI BBQ will be yet,
> probably in the Fall but they will be there then if you want to look with
a
> calibrated eye.
>
> Tom Danley
> ServoDrive
>
> The thing about patents is that you can't build and sell a patented idea
> (legally) but you can build things for you self.
>
>
>
>
>
>
=========================================================================
From: irishtom@webtv.net (tom brennan)
Subject: Re: [JN] I can let you in on something new now.
Date: Sat, 8 May 1999 00:23:55 -0500 (CDT)
Source: Sound Digest Archive v02.n138
Gee Tom, just when I was thinking my "new" JBL 2470s with Radians on
PAudio horns were the way to go, now you gotta' go and come up with
something new. :-)
Tom Brennan
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: [JN] IC database
Date: Thu, 01 Jul 1999 22:32:39 +0200
Source: Sound Digest Archive v02.n193
Hoi,
Hier:
http://www.questlink.com/ssuid:S8O9z00038Y0001qdTLaER0kBa/
vindt je practisch alle ICs en hun data.
groeten,
- -
Guido
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: Re: [JN] Ideas to run a 1625 in SE?
Date: Tue, 4 Jan 2000 16:49:28 -0500
Source: Sound Digest Archive v02.n385
>
>Anyway, I have a surplus power tranny that measures about 730VAC no load.
>I've yet to put in in a circuit to test what the loaded voltage might be, but
>I'm guessing between 400 and 450V using a 5R4G to get the most drop (Yeah, I
>know, Slagle...).
hey bud, watch it...
if you reduce the size of the first cap you can easily get the voltage you
need... pick whatever rectifer you have on hand and just tweek the first
cap to get the voltage you need.
i find choke input sounds best, full cap input worst, the smaller you keep
the first cap the more you improve the sound... i don't know if i buy that
choke input sounds better because of regulation, i think it makes the power
supply generate less hash in both directions... whatever you do keep the
first cap an oiler... cap input with plastic caps to me is a nasty thing...
its easy to swap between caps in this position and the oilers aren't too
huge... this swap alone makes me believe oil caps are most natural, since
they do not add, plastic caps sound just that... bright and edgy... the oil
caps just seem better damped... and seeing 120- hundred volt plus peaks a
second sure shows this to me.
dave
=========================================================================
From: Chris Beck <europachris@netscape.net>
Subject: [JN] Ideas to run a 1625 in SE?
Date: 4 Jan 00 12:40:46 CST
Source: Sound Digest Archive v02.n385
In my quest to build an inexpensive, unconventional SE amp, I picked up some
1943 vintage RCA's, some ceramic sockets, and am looking for some plate caps
for them.
I also picked up a pair of 6SJ7GT while I was at it to possibly do a version
of the "Fi Primer" Ultralinear SE design. BTW, if anyone has a Raytheon
6SJ7GT with the mesh shield in the old OLD red white and blue boxes, I'd be
interested.
Anyway, I have a surplus power tranny that measures about 730VAC no load.
I've yet to put in in a circuit to test what the loaded voltage might be, but
I'm guessing between 400 and 450V using a 5R4G to get the most drop (Yeah, I
know, Slagle...). That sort of limits my possibilities. The 1625 will handle
triode connection up to 400V, but the screen is rated 300V for pentode
connection, and I would be way over the 350V or so recommended for the UL
connected Fi Primer circuit. I've been fiddling with the curves and have not
really come to much conclusion as to what might be best.
Currently, running it pentode with the screen supplied by some gas tubes looks
to be the best bet, similar to Blackie's amp in a past SP, not sure which
issue. I'll drive it with the 6SJ7 in pentode and run a little feedback
around the whole shebang.
I'll also have to decide on a primary Z. Looks like something over 4K would
be best at the voltage I would be running.
If anyone has ideas for a different driver circuit, operating points, etc.
please let me know. There are SO many possibilities.
Thanks for the BW.
Chris
____________________________________________________________________
Get your own FREE, personal Netscape WebMail account today at http://webmail.netscape.com.
=========================================================================
From: "Ellen Oler" <ellenoler@earthlink.net>
Subject: Re: [JN] Ideas to run a 1625 in SE?
Date: Tue, 04 Jan 2000 21:50:19 -0500
Source: Sound Digest Archive v02.n386
>Thanks for the info, Dave. I was under the impression that tuning the voltage
>with the "neither fish nor fowl" approach was not "JoeNet Approved" practice.
But it works. The objections I've seen have to do with voltage drift once
the parts drift - but since the voltage from the wall drifts too, what's the
big deal? It'll solve your problem. The two-section oilers' small section
will be perfect for this job.
>Say, what do you think of the metallized polyprop. in oil "motor run" caps?
Motor-run cap tip :
When you see a discarded A/C, it almost always has a two-section motor-run
oiler in it, most often 15 to 30 in one section and 5 to 10 in the other.
Three lugs, one is common. Price is right. The part is either in the back
near the compresser or behind a plate with the controls on it in the front.
I find at least one a month on the street here in Brooklyn. I've yet to find
two exactly alike, though.
- -j
=========================================================================
From: "Williams, Mark D." <mwilliams@unitrin.com>
Subject: [JN] Identification of a Company Mark
Date: Fri, 28 Jan 2000 16:05:39 -0600
Source: Sound Digest Archive v02.n423
Hey there listers.
I just found a transformer with very few markings on it. Any help decoding
it will be much appreciated.
The LOGO appears to be a reversed "R" integrated with a "U" slanted to the
left. I am sure I have seen this company LOGO before but cannot place it.
TIA
Mark Williams
=========================================================================
From: Dan Kerl <dlkerl@ro.com>
Subject: Re: [JN] Identification of a Company Mark
Date: Mon, 31 Jan 2000 10:20:29 -0600
Source: Sound Digest Archive v02.n427
> The LOGO appears to be a reversed "R" integrated with a "U" slanted to the
> left. I am sure I have seen this company LOGO before but cannot place it.
This is one of the Underwriter's Laboratories Inc. (UL) accreditation logos.
From
http://www.ul.com/mark/index.html
- ---------------------------------------------------------------------------
These are marks consumers rarely see because they are specifically used on
component parts that are part of a larger product or system. These
components may have restrictions on their performance or may be incomplete
in construction. The Component Recognition marking is found on a wide range
of products, including some switches, power supplies, printed wiring boards,
some kinds of industrial control equipment and thousands of other products.
Products intended for Canada carry the Recognized Component mark "C."
- ---------------------------------------------------------------------------
- --
Dan Kerl
dlkerl@ro.com
=========================================================================
From: "ckg5" <ckg5@home.com>
Subject: Re: [JN] Identify AR turntable
Date: Fri, 22 Sep 2000 20:56:35 -0700
Source: Sound Digest Archive v02.n670
I have one and with some tweaking i think its good table with out breaking
the bank and if its in good shape you got a great deal i put a better arm on
mine made quite and improvment
Tony
- ----- Original Message -----
From: "Darryl Lock" <dklock@ieee.org>
To: "JoeNet" <sound@lists.io.com>; "Vintage Tube HiFi"
<vintage_tube_hifi@listbot.com>; "TNT-Audio"
<tnt-audioaddictsanon@onelist.com>
Sent: Friday, September 22, 2000 7:39 PM
Subject: [JN] Identify AR turntable
> I just picked up an AR turntable for the equivalent of about $20 US at a
> local second hand dealer. It has a suspended table. The tone-arm is simple
> but looks well made (has squarish headshell and block at the pivot point).
> The motor has a two step pulley. Speed change is by lifting the outer ring
> of the platter (it's in two pieces, a central hub and a large outer ring)
> and moving the belt manually.
>
> The only number I find is XBI 5878 .
>
> Is it any good? I read that some models (at least) of AR are well thought
> of.
>
> Is there a web page where I can get more info on this one... and maybe buy
> spares (like a spare belt).
>
>
> Darryl
>
=========================================================================
From: David Dlugos <planet10@pinc.com>
Subject: Re: [JN] Identify AR turntable
Date: Fri, 22 Sep 2000 21:05:17 -0700
Source: Sound Digest Archive v02.n670
Darryl
>I just picked up an AR turntable for the equivalent of about $20 US at a
>local second hand dealer. It has a suspended table. The tone-arm is simple
>but looks well made (has squarish headshell and block at the pivot point).
>The motor has a two step pulley. Speed change is by lifting the outer ring
>of the platter (it's in two pieces, a central hub and a large outer ring)
>and moving the belt manually.
This is a decent table. IMO the arm is the weakest part. I've converted a
few to Mayware Formula 4s, and at least 1 Grace 707 (got to keep the total
arm mass as close to the original plastic arm as possible. It's not in the
class of a Rega, but it will smoke most direct drive TTs. Probably in the
low end of the better tables. Ahead of a Conniseur -- in the notch above
with the Thorens TD160/165 (with the same arm mod).
dave
____________________
Never baptize a cat
=========================================================================
From: "Darryl Lock" <dklock@ieee.org>
Subject: [JN] Identify AR turntable
Date: Sat, 23 Sep 2000 12:39:03 +1000
Source: Sound Digest Archive v02.n670
I just picked up an AR turntable for the equivalent of about $20 US at a
local second hand dealer. It has a suspended table. The tone-arm is simple
but looks well made (has squarish headshell and block at the pivot point).
The motor has a two step pulley. Speed change is by lifting the outer ring
of the platter (it's in two pieces, a central hub and a large outer ring)
and moving the belt manually.
The only number I find is XBI 5878 .
Is it any good? I read that some models (at least) of AR are well thought
of.
Is there a web page where I can get more info on this one... and maybe buy
spares (like a spare belt).
Darryl
=========================================================================
From: "Darryl Lock" <dklock@ieee.org>
Subject: RE: [JN] Identify AR turntable
Date: Sat, 23 Sep 2000 14:19:56 +1000
Source: Sound Digest Archive v02.n670
> This is a decent table. IMO the arm is the weakest part. I've converted a
> few to Mayware Formula 4s, and at least 1 Grace 707 (got to keep the total
> arm mass as close to the original plastic arm as possible.
The original arm has a plastic headshell, but the rest is aluminium (by the
look of it).
>It's not in the
> class of a Rega, but it will smoke most direct drive TTs. Probably in the
> low end of the better tables. Ahead of a Conniseur -- in the notch above
> with the Thorens TD160/165 (with the same arm mod).
>
I'll look after it then... :-)
Thanks for the info.
Dazz
=========================================================================
From: "Mackris, Thom G." <tgmackris@vicorpinc.com>
Subject: RE: [JN] Idiot Governor wants to tax internet..
Date: Tue, 21 Dec 1999 08:59:48 -0700
Source: Sound Digest Archive v02.n368
Thanks for the "heads up" Scott.
Militias are not the answer but I suspect you knew that. Within the concept
of any "organization" you ultimately still have to deal with decisions,
voting, & a power structure & so the same control issues will ultimately
have to be dealt with. The answer lies with spreading awareness like you
have just *done* & then actually *doing* something about it.
I personally voice my political views through an organization called
"Working Assets". They are definitely left of center in their views and
against corporate ownership of media & the government.
Anyone interested can check them out at: http://www.wald.com/home.cfm
People who are using Earthlink as their ISP can shift their account to
Working Assetts with no change to your user id, password, etc. 1% of the
profits are directed to the organizations that you select annually. Your
billing for your intenet charges appears on your phone bill.
The only catch is that you also have to select them as your long distance
phone company. This is not bad, however, as they use Sprint's fibre optic
network & their rates are commensurate with the big 3 (AT&T, Sprint, MCI).
Thanks for the bandwith ...
Cheers,
Thom
- -----Original Message-----
From: Scott Grammer [mailto:tubedude@sunnetusa.net]
Sent: Tuesday, December 21, 1999 7:41 AM
To: Chris Veal; Christopher Daniel; Dan Searle; Eva Grammer; Jason
Ingram; Jeff Hensley; JoAnna Kelleher; Mitch Dickson; Ray Gershon; Sound
Practices
Subject: [JN] Idiot Governor wants to tax internet..
http://www.msnbc.com/news/347377.asp
If you think your elected representative is motivated by your wishes and
not greed, read this!
This guy actually threatened to have highway patrol officers pull over
UPS trucks, sort through packages to separate out the ones ordered over
the Internet, and follow the UPS truck to it's destination to forcibly
collect "use tax" from the recipient!
And they wonder why people join militias....
Scott.
- --
"To save every cog and wheel is the first
precaution of intelligent tinkering." -Aldo Leopold.
Sometimes I lie awake at night, and I ask, Why me? Then a voice answers,
Nothing personal. Your name just happened to come up.
=========================================================================
From: Scott Grammer <tubedude@sunnetusa.net>
Subject: [JN] Idiot Governor wants to tax internet..
Date: Tue, 21 Dec 1999 09:41:06 -0500
Source: Sound Digest Archive v02.n368
http://www.msnbc.com/news/347377.asp
If you think your elected representative is motivated by your wishes and
not greed, read this!
This guy actually threatened to have highway patrol officers pull over
UPS trucks, sort through packages to separate out the ones ordered over
the Internet, and follow the UPS truck to it's destination to forcibly
collect "use tax" from the recipient!
And they wonder why people join militias....
Scott.
- --
"To save every cog and wheel is the first
precaution of intelligent tinkering." -Aldo Leopold.
Sometimes I lie awake at night, and I ask, Why me? Then a voice answers,
Nothing personal. Your name just happened to come up.
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: [JN] RE:Idiot Governor wants to tax internet..
Date: Tue, 21 Dec 1999 10:26:20 -0500
Source: Sound Digest Archive v02.n368
> http://www.msnbc.com/news/347377.asp
>
> If you think your elected representative is motivated by your wishes and
> not greed, read this!
>
> This guy actually threatened to have highway patrol officers pull over
> UPS trucks, sort through packages to separate out the ones ordered over
> the Internet, and follow the UPS truck to it's destination to forcibly
> collect "use tax" from the recipient!
>
> And they wonder why people join militias....
>
Hi
I would venture that he is not an "idiot" but rather like other
opportunistic parasites infesting essentially all levels of government,
simply is hungrily eyeing a "new" un tapped source of blood.
The primary danger any bureaucracy poses is that its first duty is to
expand (regardless if its needed or not, good or not) and then somewhere
down the list is to serve its founding cause.
This IS why the founders of the constitution put in so many checks and
balances, even to the extent of allowing the populace to own guns so
that worst case the government could still be taken back by the people
(If in any doubt about the intent, go read the minutes of the debate on
the 2nd amendment).
I'm sure the founders would also be shocked at the level of violence we
and the police tolerate, the idea of allowing violence to be a staple of
children's (and our) entertainment and the "hero worship" of people that
are skillful handling a ball would also be shocking I suspect. Back
then Hero's were people that uncommonly brave or noble things and set a
standard that others tried to achieve and violence was considered
uncivilized..
Like that say, "a government program struggles to die long after its no
longer needed or wanted".
There are many examples of very costly military hardware that the armed
services didn't want or ask for that was built because of this need to
expand mentality.
50+ years after the last rural area received electricity, we still have
the "Rural Electrification Project" helping to drain our wallets as well
as countless other money burners that just won't die simply because
there part of the bureaucracy and the poor drones working there have no
place to go..
Serving no useful purpose (un like a for profit business or persons
finances) is apparently not enough justification to change things,
infact often if they cut something wasteful, its actually a negative
because next year there budget will be smaller.
My mom worked at a local High school and saw this kind of crap all the
time.
One year they had nearly 100K left in the budget at the end of the year,
the principal went and bought a big $55K color copy center which was
then stored in a locked in a room for 5 years (accumulating a total of 3
hours use) at which time is was traded in at a huge loss. The rest of
the money was spent on new hardwood desks, the old desks (perfectly good
and only a few years old) were hauled to the second floor where they
were pushed out a 2nd floor loading bay where they crashed to the ground
smashing to bits. My mom had asked if she could have one and was told
they must be destroyed as to not have any value in the "write off". What
kind of BS is this ?(its bureaucracy standard operating procedure).
The real problem is you get more of what you subsidize.
As long as bureaucracies are rewarded for waste and penalized for
efficiency (as many of the current funding arrangements do) it will ever
increase. As long as local / state / national governments see expansion
as there primary goal rather than serving the public (the actual
original intent) then there will be an excess of such parasites.
Eliminating all the waste would also cause problems too, where would
most of these people be able to find an honest job, especially with the
work ethic and attitude many have. What percentage could adapt to a life
of productive work?
What would the gov't do with the huge budget surplus? would they address
"Real problems"? or would so many of our issues continue to serve as
fund raising vehicles, rallying points for candidates rather than
actually trying to solve the problem?.
Slightly sarcastic on this cold winter morning. (was 1 deg F when I got
up)
Happy Holidays really
Tom
=========================================================================
From: "gtrmkr" <gtrmkr@wans.net>
Subject: Re: [JN] Idiot Governor wants to tax internet..
Date: Tue, 21 Dec 1999 16:35:50 -0500
Source: Sound Digest Archive v02.n368
Ditto on Working Assets. I'm subscribed to their long distance service--not
the cheapest around, but I like their idea of "profit sharing." I do think
their premise is a bit of a marketing gimmick to attract us left-of-center
types, and on that score doesn't distinguish them greatly from the
competition. But to get anywhere with that kind of mission you have to play
the marketplace game, and the idea is right (or left?). A worthy model for
other corporate entities.
Happy Holidays to all!
Jim
> Thanks for the "heads up" Scott.
>
> Militias are not the answer but I suspect you knew that. Within the
concept
> of any "organization" you ultimately still have to deal with decisions,
> voting, & a power structure & so the same control issues will ultimately
> have to be dealt with. The answer lies with spreading awareness like you
> have just *done* & then actually *doing* something about it.
>
> I personally voice my political views through an organization called
> "Working Assets". They are definitely left of center in their views and
> against corporate ownership of media & the government.
>
> Anyone interested can check them out at: http://www.wald.com/home.cfm
>
> People who are using Earthlink as their ISP can shift their account to
> Working Assetts with no change to your user id, password, etc. 1% of the
> profits are directed to the organizations that you select annually. Your
> billing for your intenet charges appears on your phone bill.
>
> The only catch is that you also have to select them as your long distance
> phone company. This is not bad, however, as they use Sprint's fibre optic
> network & their rates are commensurate with the big 3 (AT&T, Sprint, MCI).
>
> Thanks for the bandwith ...
>
> Cheers,
> Thom
>
> -----Original Message-----
> From: Scott Grammer [mailto:tubedude@sunnetusa.net]
> Sent: Tuesday, December 21, 1999 7:41 AM
> To: Chris Veal; Christopher Daniel; Dan Searle; Eva Grammer; Jason
> Ingram; Jeff Hensley; JoAnna Kelleher; Mitch Dickson; Ray Gershon; Sound
> Practices
> Subject: [JN] Idiot Governor wants to tax internet..
>
>
> http://www.msnbc.com/news/347377.asp
>
> If you think your elected representative is motivated by your wishes and
> not greed, read this!
>
> This guy actually threatened to have highway patrol officers pull over
> UPS trucks, sort through packages to separate out the ones ordered over
> the Internet, and follow the UPS truck to it's destination to forcibly
> collect "use tax" from the recipient!
>
> And they wonder why people join militias....
>
> Scott.
> --
> "To save every cog and wheel is the first
> precaution of intelligent tinkering." -Aldo Leopold.
>
> Sometimes I lie awake at night, and I ask, Why me? Then a voice answers,
> Nothing personal. Your name just happened to come up.
>
=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: [JN] IDSTWT
Date: Mon, 22 Nov 1999 20:31:12 GMT
Source: Sound Digest Archive v02.n341
Hi all,
(IDSTWT - I did something this weekend too)....
I finally fired up the final version my revised Poweramp in the system. It's
a kinda bastardised Verdier/Maison l'Audiophile and WECO91 Mongrel kind of
thing.
This is now operating a 300B in Self Bias mode, very close to the original
WECO91 Operating Point. Driver is a WECO91 second stage on some serious
steroids, using a Svetlana SV83 (or any EL84 lookalike). Drive Impedance is
down by almost the factor 10....
The Amplifier uses plenty of large size and expensive (actually quite
reasonable) Polypropylen Capacitors, the only 'lytics are in the SV83
Cathode (some Elna Silmic) and the DC Supply for the 300B Heaters. All
resistors are my favourite NOS non inductive power wirewounds. The only
exception are Gridstoppers, all of which are Allen Bradly "Brown Devils".
All other heaters are AC.... I did try the Hum cancellation techniques Steve
Bench suggests for the 300B's, but I did not get the amp quiet enough for my
Speakers (103db/W/m).... Also, different Types of 300B like valves (read
chinse Firecrackers vs. Svetlana) compensate very differently.
The main PSU is 2 X GZ34 and a Verdier Style Regulator (6AS7 X 2 & EF86 - I
repented from using the E810F as Regulator Valve - actually the SV83 socket
is wired so that I can fit the E810F in the Input with little fuss) and very
little Capacitance (40uF before and after the Regulator).
After some faffling about for a while I chucked the Zenners in the Reference
out and stuck a Neon Reference (ZZ1000) in there.... Much better, much more
natural.
The whole Amplifier seriosuly surprised me. I expected it to be a step down
from the Fugue Design, yet in most areas it is easily the equal. However the
tonality is somehow a lot nicer. For some strange reason the Bass also seems
inproved....
All in all I feel that loosing the SS Rectifiers and much more so the Zenner
Reference contributed most to the increased naturalness and relaxed sound I
get. The Combo of SV83 (or EL84) in penthode mode seems to have a livelyness
and delicacy that harmonises well with the somewhat stately and voluptous
300B Sound....
Anyway, I like that Amp.... A lot....
Oh, BTW, Penthodes used the right way can swing loads of Volts somewhat more
linear than triodes.... Believe it or not....
See ya from cold, damp and foggy London Town....
Later Thorsten
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
=========================================================================
From: Patrick Currie <tubesguy@chorus.net>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Tue, 23 Nov 1999 19:22:15 -0600 (CST)
Source: Sound Digest Archive v02.n343
>Oh, BTW, Penthodes used the right way can swing loads of Volts somewhat more
>linear than triodes.... Believe it or not....
>
>See ya from cold, damp and foggy London Town....
>
>Later Thorsten
Hmm ...
I've been hot on pentode drivers ever since Tom Ronan showed up with a 91
clone years ago. It remains the richest, most wonderful sounding amp I've
had in the house, and I've had a bunch, many of them my own, and therefore
wonderful in their own right, of course.
So Thorsten likes them, John Levreault likes them, Torbjorn likes them
(thanks for the suggestion) and, I suspect, others do too. But what am I to
make of this little excerpt from an amp review, by our friend and wu-ster,
Herb, in the latest issue of "Listener"?
"You see, the surprising thing about pentodes driving directly-heated
triodes (as opposed to pentodes driving pentodes) is that at very low
signal levels where the 6SJ7 [the WECO 91 driver] is only swinging a few
volts, distortion is very low ... [w]hen this kind of pentode is working at
these low-input/low-output voltages, its distortion products are even less
than triodes! ...
You see, there is a catch ... [a]s the pentode driver is asked to swing
more volts, the distortion rises at a logarithmic rate ... sadly, when the
tiny pentode is asked to swing this kind of voltage [80 volts is
mentioned], the distortion goes wild, out of control, and the music gets
thick and harsh and those voices that were clear just a moment ago are now
generalized and lost in the electronic hash." The reviewer refers to
6SJ7-300B amps, including those he designed and sold, as "naive and weak."
Thoughts? - Pat
=========================================================================
From: houndman@onix.com
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Wed, 24 Nov 1999 07:05:18 -0500
Source: Sound Digest Archive v02.n343
where can I get more info on this 91 clone ??
- -----------
\/ince Fontana
phila, pa. usa
houndman@onix.com
Don't do Winders. Can't on ENIAC <electronic numerical intergrator &
computer>
=========================================================================
From: John Levreault <jlevro@mediaone.net>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Wed, 24 Nov 1999 08:38:32 -0500
Source: Sound Digest Archive v02.n343
Patrick Currie wrote:
> So Thorsten likes them, John Levreault likes them, Torbjorn likes them
> (thanks for the suggestion) and, I suspect, others do too. But what am I to
> make of this little excerpt from an amp review, by our friend and wu-ster,
> Herb, in the latest issue of "Listener"?
>
> "You see, the surprising thing about pentodes driving directly-heated
> triodes (as opposed to pentodes driving pentodes) is that at very low
> signal levels where the 6SJ7 [the WECO 91 driver] is only swinging a few
> volts, distortion is very low ... [w]hen this kind of pentode is working at
> these low-input/low-output voltages, its distortion products are even less
> than triodes! ...
>
> You see, there is a catch ... [a]s the pentode driver is asked to swing
> more volts, the distortion rises at a logarithmic rate ... sadly, when the
> tiny pentode is asked to swing this kind of voltage [80 volts is
> mentioned], the distortion goes wild, out of control, and the music gets
> thick and harsh and those voices that were clear just a moment ago are now
> generalized and lost in the electronic hash." The reviewer refers to
> 6SJ7-300B amps, including those he designed and sold, as "naive and weak."
>
> Thoughts? - Pat
Yeah. Don't use a "...tiny pentode..."
JL
=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Wed, 24 Nov 1999 10:57:13 GMT
Source: Sound Digest Archive v02.n343
Hi there,
>I've been hot on pentode drivers ever since Tom Ronan showed up with a 91
>clone years ago. It remains the richest, most wonderful sounding amp I've
>had in the house,
Yes, same here.... And don't forget, the whole Amplifier currently runs on
current production russian Valves.... I shudder at the though what it will
do with Mullard GZ34's and Tung Sol 6AS7 in the PSU and Mullard E84L as
Drivers....
>So Thorsten likes them, John Levreault likes them, Torbjorn likes them
>(thanks for the suggestion) and, I suspect, others do too.
Yes. I had some feedback from the pac rim and west coast on my first ETM
Article on the Amplifier where I pronounced the WECO 91 "The Amplifier of
the Millenium" (oaky, the century actually). Many people share my
sentiments.
>But what am I to make of this little excerpt from an amp review, by our
>friend and wu-ster, Herb, in the latest issue of "Listener"?
I noticed Herb is not hot on Penthode Drivers.
>"You see, the surprising thing about pentodes driving directly-heated
>triodes (as opposed to pentodes driving pentodes) is that at very low
>signal levels where the 6SJ7 [the WECO 91 driver] is only swinging a few
>volts, distortion is very low ...
Indeed.
>[w]hen this kind of pentode is working at these low-input/low-output
>voltages, its distortion products are even less than triodes! ...
Yup.
>You see, there is a catch ... [a]s the pentode driver is asked to swing
>more volts, the distortion rises at a logarithmic rate ...
Ahhhmmm. Yes. And it is almost PURELY 2nd Harmonics (at least for the EL84
at the operating point I use).... All higher order stuff is majorly DOWN on
the 2nd Harmonics. And with a EL84 it still is lower at 50V RMS into the
Grid of the 300B than a 5842/417A loaded by an Interstage Transformer....
>sadly, when the tiny pentode is asked to swing this kind of voltage [80
>volts is mentioned], the distortion goes wild, out of control, and the
>music gets thick and harsh and those voices that were clear just a moment
>ago are now generalized and lost in the electronic hash."
Hmmmm. I have no such problems. But I listen with 103db/W/m Horns so all out
power is no issue. At high levels (near 10W) the Amplifier starts cancelling
Distortion (not as a deliberate act of design by me but because of the
combination of the 300B drawing Grid Current and because the Penthode starts
cranking up the THD....) quite agressively, leaving a 3rd Distortion as one
would expect from the Datasheets for this Operating Point (80mA, 350V, 2.4k
Load) but very little 2nd Order Harmonics....
The whole rest of the spectrum is well behaved and nothing goes majfar
scanbark as far as I can see.... I suppose I'll have to get the Amplifier
down to Morgan Jones and put it on the AP-1 he keeps around....
Ciao Thorsten
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
=========================================================================
From: Jeremy Epstein <jepstein@shwd.com>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Wed, 24 Nov 1999 08:58:56 -0500
Source: Sound Digest Archive v02.n344
> where can I get more info on this 91 clone ??
Look on Angela Instruments web site www.angela.com, under the projects
section, he has a complete WE91 - style amp with schematic and all parts
priced out etc - a make-your-own-kit.
- -j
- --
=====================================
Jeremy Epstein .... jepstein@shwd.com
=====================================
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Wed, 24 Nov 1999 09:44:28 -0700
Source: Sound Digest Archive v02.n344
Patrick Currie wrote:
>>Oh, BTW, Penthodes used the right way can swing loads of Volts somewhat more
>>linear than triodes.... Believe it or not....
>>
>>See ya from cold, damp and foggy London Town....
>>
>>Later Thorsten
SNIP
> You see, there is a catch ... [a]s the pentode driver is asked to swing
> more volts, the distortion rises at a logarithmic rate ... sadly, when the
> tiny pentode is asked to swing this kind of voltage [80 volts is
> mentioned], the distortion goes wild, out of control, and the music gets
> thick and harsh and those voices that were clear just a moment ago are now
> generalized and lost in the electronic hash." The reviewer refers to
> 6SJ7-300B amps, including those he designed and sold, as "naive and weak."
>
> Thoughts? - Pat
>
===========================
Hi:
A few years ago I was playing around with driving push-pull 813s using
resistively-loaded 6AU6s. Those were cap coupled into push-pull choke,
grid-loads.
Eventually, I set-up a 5687 cathode follower to both provide DC screen
voltage and a some feedback to the 6AU6s' screens.
This proved to have some remarkable results. I found that at a certain
screen voltage - about 90V as I recall - and about 6dB of feedback the
distortion products literally fell off the map.
As the DC level on the screen was varied, a deep null in distortion was
found. Upon setting up this circuit on the Tek 570 curve tracer I was
rewarded by the the most beautiful set of plate curves I'd ever seen, tube
or solid state.
To get the amount of f/b used, I simply put a 250K pot as the plate load
and cap coupled from the wiper to the grid of the 5687. Note that just a few
dB of f/b will drop the output Z of a pentode stage by about an order of
magnitude so driving the Miller of a big triode becomes, essentially, a
non-issue.
Sonically it was wonderful, and I've been thinking lately about using it
to run 845s at it surely will swing the req'd grid drive.
The work of Allen Wright and others on linearized cathode followers is,
of course, very useful in creating a better - more linear - cathode follower
for use in this circuit.
Bill - Pearl, Inc.
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] IDSTWT- pentode drivers
Date: Wed, 24 Nov 1999 11:13:07 -0500
Source: Sound Digest Archive v02.n344
now that i've come out of the closet regarding
my SS amp building experiences,
i though i'd chime in on pentode drivers, too....
if you look at typical curves for pentodes
you will notice that at higher plate voltages
they are relatively flat, and almost horizontal.
if you pick a single plate voltage value, and follow
that vertical line, the grid bias curves start to
bunch together at lower currents.
as you increase in plate current, the curves
continually spread out.
this leads to a predominance of even order distortion, just like
a normally loaded triode.
it is almost as if you could reverse the I-V axes,
triodes with constant current and pentodes with constant
voltage look very similar.....
so the trick to geting low and mostly 2nd harmonic distortion
with triodes is HIGH load impedance,
and the trick to geting low and mostly 2nd harmonic distortion
with pentodes is LOW load impedance.
in general, the suggested operating points for pentodes is
geared toward maximum gain and maximum voltage swing.
in order to achieve this you must use a high plate load
impedance.
the normal process is to pick the "knee" of the
0V bias curve (at low voltage high current) as the one
end of your load line. and pick some operating point and load
that extends as far to the right (higher plate voltage)
as possible.
in order to minimise (2nd harmonic) distortion,
the choice of operating point is supposed to give the most symmetric plate
current swing as compared to the grid swing.
(i.e., if you get 20 mA at Ec=0V (maximum grid swing),
you'd like your operating
point to be near 10mA at say -2V, and at -4V (minimum grid swing)
you want to be as close to 0mA as possible. )
this approach ignores the fact that at lower plate voltage
the grid bias curves start to bunch together again
as you near the "knee" region.
this leads to compression on both ends => 3rd harmonic distortion.
so....
i suggest that driver pentodes should be operated at reasonably
high plate voltage (to avoid the "knees"),
and be operated with as low of a plate load impedance as you can tolerate
(still make some swing).
power pentodes give you more flexibility 'cause they can
burn some power to give you the current bias you want...
you can probably "tune" for lowest distortion with the
screen bias...
so what's so wrong with pentodes?
operator error, i think....
bob.d.
=========================================================================
From: John Levreault <jlevro@mediaone.net>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Wed, 24 Nov 1999 12:24:56 -0500
Source: Sound Digest Archive v02.n344
PEARL Cust Serv wrote:
>
> The work of Allen Wright and others on linearized cathode followers is,
> of course, very useful in creating a better - more linear - cathode follower
> for use in this circuit.
This is one of the strengths, though, of power pentodes like the 6AG7, or, to a
lesser extent, the 6AC7. You can run enough plate current through them so that the
plate load drops into the 5-10K range, providing a reasonably low driving point
impedance for a power triode.
JL
=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Wed, 24 Nov 1999 17:45:33 GMT
Source: Sound Digest Archive v02.n344
Hi there,
Bill wrote:
>The work of Allen Wright and others on linearized cathode followers is, of
>course, very useful in creating a better - more linear - cathode follower
>for use in this circuit.
Yes. That said, I used before the EL84 Driver a Driver stage that combined
the Mu Stage and Allens Super Linear Follower direct-coupled.
I arrived at that after resistively Loaded Triodes and Inductively loaded
Triodes. Non of the triodes alone could really cut the mustard. So the
"Super-Mu Stage was a smart way out.
Having converte to RC Coupling and now using the Pentode Driver without
Cathode Follower showed me that (AGAIN) the Cathode follower got in the way.
I suspect I dislike even the faint remaining sonic signature of the Super
Linear Follower.... Once lost everything sounded more natural, less
mechnical.
John wrote:
>This is one of the strengths, though, of power pentodes like the 6AG7, or,
>to a lesser extent, the 6AC7.
Or 6BQ5 or TS49....
>You can run enough plate current through them so that the
>plate load drops into the 5-10K range, providing a reasonably low driving
>point impedance for a power triode.
YES, YES, YES!
I load the SV83/EL84/6BQ5 Anode with 12k.... There is still WAY MORE gain
than I need.
Later Thorsten
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Wed, 24 Nov 1999 16:24:53 -0700
Source: Sound Digest Archive v02.n345
John Levreault wrote:
> PEARL Cust Serv wrote:
>>
>> The work of Allen Wright and others on linearized cathode followers is,
>> of course, very useful in creating a better - more linear - cathode follower
>> for use in this circuit.
>
> This is one of the strengths, though, of power pentodes like the 6AG7,
> or, to a lesser extent, the 6AC7. You can run enough plate current
> through them so that the plate load drops into the 5-10K range,
> providing a reasonably low driving point impedance for a power
> triode.
>
> JL
===================================
Hi:
I hope you've not mis-read me here: I'm not using the CF to drive the
load on the stage, rather, I'm using it to drive the screen of the pentode
to radically lower both that tube's output Z and distortion. The load is
conventionally driven from the pentode's plate.
A distortion figure - hardly believable I realize - of something on the
order of .03% @ 100Vrms into 100K seems to ring true.
Bearing in mind that I did this work five of six years ago, this number
might be a >< little >< off the mark - but not by much. I remember wondering
if my distortion analyzer had fritzed itself without my having noticed and I
did some re-cal procedures on it just to be sure . . . .
This sort of performance was subsequently achieved with the 7199.
There, I simply used the triode in the same envelope for the screen-driving
functions.
Best regards,
Bill Perkins,
PEARL, Inc.
Unit 200, 2137 33rd Ave. SW.,
Calgary, AB.,
Canada T2T 1Z7
Ph. 1 403 244 4434
Fx. 1 403 244 9026
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Wed, 24 Nov 1999 18:57:54 EST
Source: Sound Digest Archive v02.n345
In a message dated 11/24/99 5:38:34 PM Central Standard Time,
custserv@pearl-hifi.com writes:
<< I remember wondering
if my distortion analyzer had fritzed itself without my having noticed and I
did some re-cal procedures on it just to be sure . . . . >>
Hi Joes,
Yup. I used to doubt my trusty H-P 334A quite often.
Building a single unit and tuning the circuits to the specific tube in
circuit is nearly magical.
And then the Music!
Happy Ears!
Al B^}
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Tue, 30 Nov 1999 14:47:01 -0500
Source: Sound Digest Archive v02.n349
Peter asked:
>>>Instead of a cathode follower, why not load that hi-Gm tube you should
be using anyway with a very low (1/Gm) plate resistor?<<<
Good idea Peter - but perhaps not for a cable driver line stage... To be
able to use non shielded interconnects without any hum/buzz pickup, I need
no than 100R output Z from a line amp. But if you anode loaded a hi Gm tube
with 100R then at even insane running currents the output signal level
before clipping might be just enough- but you would have minimal
headroom...
With common ol' 6922's I can get the desired 100R OPZ with the SLCF design
- - yet it easily swings 100V P-P on a 200V supply.
BTW, I finally have the RTP3C pramp running and in the system. This is the
unit shown in the Preamp Kit Newsletter on our website. The schematic is
the same as the RTP3A schematic on the site and in the TPCB - except that
the line stage is all tube, a triode replacing the 2SK147 input fet..
This unit is so stunningly better than a similar design (RTP5) that uses
power MOSFETs (but only) as current sources and CF cascode buffers that I
really am rethinking my usage of such devices - anywhere!
Munich JoeNetters (and all others who are stopping over here for the beer
and more) are invited to come and hear the all tube difference!
Allen (VSE)
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Tue, 30 Nov 1999 16:49:03 -0700
Source: Sound Digest Archive v02.n349
Hi Allen, All:
SNIP
> BTW, I finally have the RTP3C pramp running and in the system. This is the
> unit shown in the Preamp Kit Newsletter on our website. The schematic is
> the same as the RTP3A schematic on the site and in the TPCB - except that
> the line stage is all tube, a triode replacing the 2SK147 input fet..
>
> This unit is so stunningly better than a similar design (RTP5) that uses
> power MOSFETs (but only) as current sources and CF cascode buffers that I
> really am rethinking my usage of such devices - anywhere!
You know, I really wondered when I saw those in there.
Hitachi make a VERY low input (20pF) and reverse transfer C (2.5pF),
250V MOSFET called a 2SK511. It's used as a video driver, etc. . . .
I've had pretty good luck with this but it ain't no glassbody GlowFET
> Munich JoeNetters (and all others who are stopping over here for the beer
> and more) are invited to come and hear the all tube difference!
>
> Allen (VSE)
>
Bill - PEARL, Inc.
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: Re: [JN] IDSTWT- pentode drivers
Date: Wed, 1 Dec 1999 15:52:53 -0500
Source: Sound Digest Archive v02.n350
Bill wrote:
>>> You know, I really wondered when I saw those in there.
Hitachi make a VERY low input (20pF) and reverse transfer C (2.5pF),
250V MOSFET called a 2SK511. It's used as a video driver, etc. . . .
I've had pretty good luck with this but it ain't no glassbody
GlowFET<<<
I will try this device - thanks for the recommendation.
The only reason I used these MOSFETs was to make a do-able package, and to
be able to be used as a retro-fit upgrade in a number of units out in the
field.
And the MOSFET version of the SLCF was still much better than any other low
OPZ line amp I tested with a similar number of tube sockets. Killed the
SRPP and the mu-follower.
But who cares about tube numbers - two 6922's will do it all tube for a SE
version and 4 for differential. Or 5 if you want a cascode input - like I
do!
Allen (VSE)
=========================================================================
From: "Thomas Sylvester" <TRS@carlsmith.com>
Subject: [JN] IF Gaudi had designed tube amps . . .
Date: Thu, 26 Jul 2001 16:44:41 -1000
Source: Sound Digest Archive v02.n934
Check this out:
http://www.chuokai-toyama.or.jp/odeo/
Couldn't find schematics at this site; maybe one of our Japanese Joes can help?
=========================================================================
From: "Jan Hass" <jh@hifi-analyse.dk>
Subject: SV: [JN] IF Gaudi had designed tube amps . . .
Date: Fri, 27 Jul 2001 11:16:19 +0200
Source: Sound Digest Archive v02.n934
Hi Thomas
Thanks for sharing. Marvellous work !
How would you rate the WAF factor ??
greats Jan
- -----Oprindelig meddelelse-----
Fra: owner-sound@lists.io.com [mailto:owner-sound@lists.io.com]Pa vegne
af Thomas Sylvester
Sendt: 27. juli 2001 04:45
Til: sound@io.com
Emne: [JN] IF Gaudi had designed tube amps . . .
Check this out:
http://www.chuokai-toyama.or.jp/odeo/
Couldn't find schematics at this site; maybe one of our Japanese Joes can
help?
=========================================================================
From: Rick Francis <rfrancis@glasscity.net>
Subject: [JN] If music is like sex WAS Jazz is like Inedible pizza
Date: Wed, 21 Feb 2001 20:48:01 -0500
Source: Sound Digest Archive v02.n815
Douglas Purl wrote:
>
> Though I have never heard him, I do know that Bob Marley is a dead saint
> in whose revered name people regularly take drugs, and that a whole
> generation of erstwhile hippies still insist that an astonishingly
> untalented nose-whiner named Bob Zimmerman is/was a man of note.
Interesting that you pick these two, who were focal points of shared
experience for so many. Either could be used to contradict your picture
of a decline from shared social experience to onanistic self-pleasure.
> Great jazz and great swing do one of two things: they set the toes to
> tapping or bodies to swaying. In other words, they are sensuous
> experiences that seque into the sensual, and set people to dancing.
Sounds like reggae to me. Maybe your only gripe is the appeal to a
social unity independent of the couples-romance-straightsex analogy you
find appealing in big band dancing? Or since you brought up couples sex
and masturbation as analogies, I suppose "orgiastic" is the missing
adjective -- though I have my doubts about the analogy to begin with.
The political aspect of Marley's music begs for much than a comparison
to orgiastic dance music (rave?).
If there's a communal experience around music, but you don't share it,
can you say it does not exist?
I enjoyed reading your diatribe, though I thought it was missing a line
or two about the decline of literature, food, and public transportation.
It recalled to mind some snippet that survived from ca. 1500 B.C., which
translated to something like "The younger generation has no respect for
tradition..."
Rick
=========================================================================
From: Chris and Susan Beck <n9zes@execpc.com>
Subject: [JN] ignore
Date: Tue, 02 Feb 1999 17:53:13 -0600
Source: Sound Digest Archive v02.n024
test
=========================================================================
From: "Bert Doppenberg" <sales@bd-design.nl>
Subject: [JN] IGNORE: (unsubscribe ->>> subscribe)
Date: Tue, 13 Feb 2001 23:21:23 +0100
Source: Sound Digest Archive v02.n807
This is a multi-part message in MIME format.
- ------=_NextPart_000_005E_01C09613.ADECDBA0
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charset="iso-8859-1"
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Sorry guy's, just checking if it worked out okay....
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<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3D"Comic Sans MS" size=3D2>Sorry guy's, just checking if =
it worked=20
out okay....</FONT></DIV></BODY></HTML>
- ------=_NextPart_000_005E_01C09613.ADECDBA0--
=========================================================================
From: "Larry D. Moore" <l-moore@onu.edu>
Subject: [JN] Iguana plans
Date: Thu, 04 Nov 1999 10:38:18 -0500
Source: Sound Digest Archive v02.n321
Thankfully, Roscoe has consented to posting the Iguana info! Look for a
link soon.
L.D. Moore
=========================================================================
From: "Larry D. Moore" <l-moore@onu.edu>
Subject: [JN] Iguana plans in the public domain
Date: Thu, 04 Nov 1999 08:13:52 -0500
Source: Sound Digest Archive v02.n321
Gang:
I've decided to put the Iguana schematic in the public domain. Several
people have asked me about it over the last couple of days and I figured it
was time. What I need is some web space to put it and someone to do it.
The plans contain a complete parts list in excel, schematic in AutoCAD LT,
and top plate drilling diagram, also in AutoCAD LT.
Can anyone help??
L.D. Moore
=========================================================================
From: blackie <tubesville@yahoo.com>
Subject: Re: [JN] Iguana plans in the public domain
Date: Thu, 4 Nov 1999 12:34:35 -0800 (PST)
Source: Sound Digest Archive v02.n322
- --- "Larry D. Moore" <l-moore@onu.edu> wrote:
> Gang:
>
> I've decided to put the Iguana schematic in the
> public domain. What I need is some web space to put
>it
> and someone to do it.
how big??
I think I could help..
=====
blackie
blackie@tubesville.com
www.tubesville.com
__________________________________________________
Do You Yahoo!?
Bid and sell for free at http://auctions.yahoo.com
=========================================================================
From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
Subject: [JN] I have a web site at last!
Date: Mon, 23 Apr 2001 15:33:58 +0100 (BST)
Source: Sound Digest Archive v02.n873
Well it is about time I put something up. All that is there at the
moment is my original op amp phono stage with DC servo, but it might be
of interest to somebody. I will add to the site as time goes on. Sorry
about the naff url at the moment..
http://193.62.175.164
Best,
Simon
Simon Busbridge, BSc(Hons) PhD CPhys MInstP
School of Engineering
University of Brighton
Lewes Road
Moulsecoomb
Brighton BN2 4GJ
UNITED KINGDOM
Tel: 0044 (0)1273 642542
Fax: 0044 (0)1273 642327/642301
e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
=========================================================================
From: Kurt Steffensen <kurt-steffensen@teliamail.dk>
Subject: [JN] I humble bend my neck !
Date: Wed, 23 Aug 2000 00:44:27 +0200
Source: Sound Digest Archive v02.n638
So he did it again....
Can you imagine an amplifier without resistors....
Well , that is not to hard to do...
But if there is no capacitors either , it does come quite a bit harder..
Then can you imagine that amplifier , connected to a PSU , that has NO
capacitors or even resistors
Well , that is not that difficult to IMAGINE , but can you actualy
picture the schematic ?
Now , THAT one is a true nut to crack.
Then take it a little further....
( Oh , yes , why not push it to the limit ? :-)
Do make that PSU , a true tube regulated PSU...
I am sure that has never been done before...
Never the less , that is exactly what our grand master Steve Bench has
done :-)
Go check it out on the worlds best tube web page.
http://members.aol.com/sbench101/
And to please , all you shunt freaks , it is a genuine choke in , shunt
regulated power supply. !
When you see the circuit you will realise that it has to be.
The circuit seems quite , at first glance , but there is a lot of well
thought details.
In fact if you change as much as ONE component , the chance is , that
you will ruin the whole thing.
Hats of to Steve , once again , Joes.
He is a true master.
Even if the thing sounded like total shit ( Which I KNOW it does not ) ,
it is so clever carried out , that you just have to build it.
Are you listening , J ?
There you go , as you would put it.
Indeed , here we go ;-)
Thanks , Steve for sharing all that magic with us.
If you guys thinks that we must have seen the best from his hand , I
urge you to watch his webpage closely.
I know he has something even better cooking.. Hard to imagine , but
there you go.. ( C)Jeremy Epstein.
( BTW , Jeremy , guess what came in the post today from AES , 8 weeks
after we ordered ? )
What a brilliant list this is. So many gifted talents , and so nice and
good people....
I want to hire Steve for my Audio company..
Does anyone have a bulletproof plan , that will have the tele company (
in which he vaste his talent now ) fire him ?
- - Kurt
=========================================================================
From: "Eric Weitzman" <eweitzman@acm.org>
Subject: RE: [JN] I humble bend my neck !
Date: Tue, 22 Aug 2000 18:29:27 -0700
Source: Sound Digest Archive v02.n639
How on earth does that 12BH7 bias the driver and the
output tubes simultaneously? And is it a constant bias?
- - Eric
=========================================================================
From: SBench@aol.com
Subject: Re: [JN] I humble bend my neck !
Date: Tue, 22 Aug 2000 22:43:03 EDT
Source: Sound Digest Archive v02.n639
In a message dated 00-08-22 21:31:21 EDT, eweitzman@acm.org writes:
<< How on earth does that 12BH7 bias the driver and the
output tubes simultaneously? And is it a constant bias?
- Eric >>
Hi Eric and all,
Input stage current causes a positive bias on the 12BH7 grids.
Since the plate load on the input stage is fairly high impedance,
(Transformer acting as constant current load) the bias is
fairly constant. See below.
The positive grid bias on the grid causes the plate of the 12BH7 to
conduct relatively heavily; and the resistance in this region is
relatively constant to slightly curved (pentode style) C.F. any DHT
operated in positive grid region.
This provides about 15 volt bias for the output section.
There is some feed-forward from the input stage to the
cathode of the output stage. That's why the polarity of the
driver transformer is important.
Similarly, due to the inverse gain of the 12BH7, there is a very slight
ammount of feedback from the cathode voltage on the output stage
feeding back causing the forward biased grid of the 12BH7 to ever
so slightly alter its grid voltage, causing a feedback path to the
input section.
The aggregate is slightly "biased" (pardon the pun) toward the
feed forward condition.
I'm still working on trying that trick with a DHT output stage :-)
Best Regards,
Steve
=========================================================================
From: "leamare" <leamare@libero.it>
Subject: I: [JN] The Terroist Actions Today And Any News From JC Morrison?
Date: Wed, 12 Sep 2001 15:11:36 +0200
Source: Sound Digest Archive v02.n965
This is a multi-part message in MIME format.
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I meant to subscribe this part.
My apologies
Armando
Please let us make the best of this horrible situation by respecting =
the=20
dead, helping the living, and not jumping to judgement regarding the=20
causality. There will be plenty of opportunities to politicize this =
tragedy;=20
please leave them off of the Joe-net!=20
Kevin Carter=20
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<DIV> </DIV>
<DIV>I meant to subscribe this part.</DIV>
<DIV>My apologies</DIV>
<DIV>Armando</DIV></BLOCKQUOTE><BR><BR>Please let us make the best =
of this=20
horrible situation by respecting the <BR>dead, helping the living, and =
not=20
jumping to judgement regarding the <BR>causality. There will be =
plenty=20
of opportunities to politicize this tragedy; <BR>please leave them off =
of the=20
Joe-net! <BR><BR>Kevin Carter</FONT> =
</FONT></BLOCKQUOTE></BODY></HTML>
- ------=_NextPart_000_00F8_01C13B9D.372A2E20--
=========================================================================
From: Christian Rintelen <christian@rintelen.ch>
Subject: [JN] iMac for sale - cheap!
Date: Wed, 04 Oct 2000 22:15:33 +0200
Source: Sound Digest Archive v02.n686
Joes,
my girlfriend is moving from NYC to Switzerland next week. She needs to
get rid of her iMac - to big for hand luggage... So here's the deal:
For $ 1800.00 cash you get
- - iMac DV Special Edition (G3, 400 MHz, 128 MB SDRAM, 20 GB, DVD-ROM,
65k internal Modem, USB/FireWire)
- - Epson Stylus Color 860
- - Kensington Trackball (plus that crappy iMac mouse)
- - 5 port USB hub
- - external Zip drive
all the software that comes with the iMac plus original copies of:
- - MS Office 98
- - Norton Utilities
- - Norton AntiVirus
The whole shebang was bought in March 2000, condition is excellent.
There is an extended warranty on everything.
Location is NYC, pick-up only (no shipping). *Hurry up - she'll be
leaving next tuesday!*
If you're interested, get in with her directly: mailto:bettina@dti.net
Thanks for the bandwith!
Christian
=========================================================================
From: David Dlugos <planet10@pinc.com>
Subject: Re: [JN] iMac for sale - cheap!
Date: Thu, 5 Oct 2000 11:22:49 -0700
Source: Sound Digest Archive v02.n687
>my girlfriend is moving from NYC to Switzerland next week. She needs to
>get rid of her iMac - to big for hand luggage... So here's the deal:
>
>For $ 1800.00 cash you get
>
>- iMac DV Special Edition etc....
this is a very good value (particularily if you can use the Office suite).
So for some Joe out there how is sick & tired of Windoz, or wants to
upgrade from their LC475 (or whatever) this is a jump-at-it!
dave
___________________
The box said "Windows 9x or better" ... so i bought a Macintosh
=========================================================================
From: "Phil Sieg" <triodelover@home.com>
Subject: [JN] Images to remember
Date: Sat, 15 Sep 2001 21:21:49 -0400
Source: Sound Digest Archive v02.n975
Joes,
I know it's time to move on, but I stumbled across some very moving images
at http://140.141.24.32/wtc/thankyou.html.
If I must remember some image from this horrid experience, it is these that
my memory will hold on to the longest.
Phil
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: [JN] IMAGINATION IS MORE IMPORTANT THAN KNOWLEDGE
Date: Wed, 24 Mar 1999 05:36:05 -0500
Source: Sound Digest Archive v02.n089
Paul wrote:
>>>>I asked one of my nuke physics prof's about this statement
one time - he said:
"....that statement only works if you are Albert Einstein - does not apply
to me and you"<<<
Brilliant! - could be the basis of a great T-Shirt - Einstein's quote on
one side and your Prof's comeback on the other...
Allen (VSE)
=========================================================================
From: Torsten.Loesch@enhar-ha.nthames.nhs.uk
Subject: Re: [JN] IMAGINATION IS MORE IMPORTANT THAN KNOWLEDGE
Date: 24 Mar 1999 11:38:13 +0000
Source: Sound Digest Archive v02.n090
Hi all,
> >>I asked one of my nuke physics prof's about this statement
> one time - he said:
>
> "....that statement only works if you are Albert Einstein - does not apply
> to me and you"<<<
>
> Brilliant! - could be the basis of a great T-Shirt - Einstein's quote on
> one side and your Prof's comeback on the other...
I would like to add that the initial Statement does apply to you and me Allen
(and quite a few others on this list)....]
I have found that much of "accepted" knowledge on the Subject of Audio is
either plainly taken out of context, misleading or outrightly a lie. Why that
is so, I can only guess...
Later Thorsten
=========================================================================
From: Zyxtan@aol.com
Subject: Re: [JN] IMAGINATION IS MORE IMPORTANT THAN KNOWLEDGE
Date: Wed, 24 Mar 1999 21:19:07 EST
Source: Sound Digest Archive v02.n092
In a message dated 3/24/99 5:42:14 AM US Eastern Standard Time,
AllenVSE@compuserve.com writes:
> Paul wrote:
> >>>>I asked one of my nuke physics prof's about this statement
> one time - he said:
>
> "....that statement only works if you are Albert Einstein - does not apply
> to me and you"<<<
>
> Brilliant! - could be the basis of a great T-Shirt - Einstein's quote on
> one side and your Prof's comeback on the other...
Allen, it's all yours to make t-shirts, buttons, and bumper stickers out
of.....just remember me in your will;-)
paul(zyxtan@aol.com)
=========================================================================
From: "P. de R. L." <triode@bow-tie.org.uk>
Subject: [JN] I may be gone some time...
Date: Sun, 5 Mar 2000 21:03:09 -0000
Source: Sound Digest Archive v02.n474
This is a multi-part message in MIME format.
- ------=_NextPart_000_001E_01BF86E6.361E03C0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
In case anyone may be trying to get in touch, my pentium 75 is about to =
go the the great shop in the sky.
I have purchased a more modern s/h rig which will need some bits from =
the old one (hard drive/cd) and given my computer expertise, it may be =
some time before I can read my mail.
As they say, "It's been"
Paul
- ------=_NextPart_000_001E_01BF86E6.361E03C0
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content=3D"text/html; charset=3Diso-8859-1" =
http-equiv=3DContent-Type>
<META content=3D"MSHTML 5.00.2314.1000" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#800080 face=3D"Century Schoolbook" size=3D2>In case =
anyone may be=20
trying to get in touch, my pentium 75 is about to go the the great shop =
in the=20
sky.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#800080 face=3D"Century Schoolbook" size=3D2>I have =
purchased a=20
more modern s/h rig which will need some bits from the old one (hard =
drive/cd)=20
and given my computer expertise, it may be some time before I can read =
my=20
mail.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#800080 face=3D"Century Schoolbook" size=3D2>As they =
say, "It's=20
been"</FONT></DIV>
<DIV> </DIV>
<DIV><FONT color=3D#800080 face=3D"Century Schoolbook"=20
size=3D2>Paul</FONT></DIV></BODY></HTML>
- ------=_NextPart_000_001E_01BF86E6.361E03C0--
=========================================================================
From: Scott Grammer <tubedude@cdc.net>
Subject: [JN] I'm back, for a visit, anyway.
Date: Tue, 25 May 1999 06:37:11 -0400
Source: Sound Digest Archive v02.n151
Hi Joes.
I'm back for a while, anyway, although I don't get to check my email as
often as I would like to. I hope you all understood I was just trying to
get people talking with my first post. I do think some of those things
are true, but I will keep which ones to myself for now, to avert any
arguements with those who disagree vehemently. I suppose I am becoming a
"kinder, gentler" tubedude in my old age.
It's good to "read" you all again.
Scott.
PS, Jean Michel LeCleach, if you're listening, please email me
privately, I need to ask you something, and I do not have your email
address.
Scott.
- --
TubeDude's Webpage of Vacuum Tube Lore! http://www.cdc.net/~tubedude/
Smoke Free Youth! http://www.cdc.net/~tubedude/smokefreeyouth.html
The Price of Privacy. http://www.cdc.net/~tubedude/privacy.html
"This is a new focus for the security community." "The actual user of
the PC - someone who can do anything they want - is the enemy."
--David Aucsmith, security architect for the Intel Pentium III.
=========================================================================
From: Carter Hendricks <carter@i1.net>
Subject: [JN] Re: I'm HERE
Date: Tue, 18 Sep 2001 00:15:10 -0500
Source: Sound Digest Archive v02.n977
> > Bill--
> >
> > I hope that you know that I was NOT
> > thinking about you in the post I just
> > sent suggesting that filters are an
> > easy fix to delete unwanted mail. What
> > you write--both technical stuff and your
> > personal contributions--is always read
> > by me, and Lynn and I were talking tonight
> > about some of the ideas you've raised
> > recently. Your posts are a good counterpoint
> > to the barking dogs.
> >
> > --Carter
=========================================================================
From: Christian Rintelen <rintelen@datacomm.ch>
Subject: [JN] I'm off...
Date: Wed, 19 Jul 2000 11:09:45 +0200
Source: Sound Digest Archive v02.n607
bye, Joes -- I'm off till August 2. See you in Ċarhus!
Christian
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: [JN] I'm Off for a Bit...
Date: Thu, 21 Jan 1999 13:56:31 -0700
Source: Sound Digest Archive v02.n006
Yo Joes:
Fyi: I'm off out of town for a few days so I'll be
slow replying to any mail. See you all later.
I guess I'll get to find out how big my e-mail box is,
there's a lot of activity on this list...
Bill Perkins, PEARL Inc.
2528 19 St. S.W., Calgary, Ab.,
Canada T2T 4X3
Ph. 1 403 244 4434 Fx. 1 403 244 9026
=========================================================================
From: Steve Van Osdell <svanos@queencity.com>
Subject: [JN] I'm OUTTA HERE!
Date: Sun, 13 Aug 2000 14:15:36 -0400
Source: Sound Digest Archive v02.n626
I will be unsubscribing to the JoeList. I was away for some years and
recently resubscribed back the first week of July. I made job changes
and moved across the country during the time I was unsubscribed, and my
audio hobby took a 'back seat'. So, now that I'm able to have the time
to start giving it attention, I thought that I would resubscribe to this
list.
However, very recent events have reminded me of things that disappointed
me with this list back several years ago, and that is what I call the
'ninnie' factor. There are a lot of nice and friendly guys on this
list, but there are also a bunch of what I call 'ninnies'. These are
people who, in my opinion, will complain about anything just to have
something to complain about, or who will 'snipe' at someone less 'in the
clic' than they are just for the fun of sniping. In other words, if a
posting has absolutely nothing to do with them, or anything they might
be interested in, they will take an opportunity to 'pick'.
Just today, I received a private email from a prominent Joe which stated
the following. I won't mention his name because it was sent privately.
"You've only been back on the list for a few days, and you're again
treating
it as your little trading post. "How much is this worth?" was a
constant
refrain the last time you were subscribed, and now you're doing it
again.
People really don't like it, and you're seeing a little of the result.
It's nice that you've got an amp built, and I'm sure people like to hear
about it and stand ready to help on future projects, and there still is
the
occasional swapmeet posting here, but, please, give it a break."
Now, I've done a search back thru my sent emails since I rejoined in
July and here is a summation if what I found.
1. I sent and exchanged 4-5 emails discussing good choices for driver
tubes and the possible sources for a 6C45pi. (nothing to do with
'trading post' issues here).
2. I posted a 1 or 2 messages about the RCA World's Fair Horn and asked
if anyone had the skills to be able to duplicate one, and that if they
did, I had an extra one they could use for making a mold. (nothing
'trading post' wise here)
3. Several postings responding to various little topics regarding
favorite CD's, CD player recommendations, and questions regarding fixing
the hum problem in my amp I built (nothing 'trading post' in these
either).
4. Couple of postings recently mentioning that RatShack has dipole
tweeters on sale for half price and asking if anyone had Andrej's email
address (nothing trading post here).
Then recently I bought some speakers and needed to do some housecleaning
to sell a few things to help pay for them, so I posted some items in
ebay and also dug out some old WE tubes I have (that most I have no idea
what they do). So, I thought I'd see if anybody here might a. know if
they were of any use, and b. if they were, offer them for sale here at a
good price before listing them on ebay. I also mentioned about my
Goodman woofers that I would sell also.
So, if a guy is going to be 'lampooned and lambasted' for running a
'little trading post' operation simply because he was doing some
housecleaning and needed to sell a few things to pay for some new
speakers (and was willing to give Joes a good deal on these things if
they would be of use to anyone to boot), then this is NOT the place I
need to be, and its NOT for me.
I can communicate with the more friendlier guys I know on this list
without being subscribed to the list anyway. There are some real
peculiar types among us good guys here is all I have to say.
Thank you very much
Steve
=========================================================================
From: "Fred Volz" <fcv@emotiveaudio.com>
Subject: Re: [JN] I'm OUTTA HERE!
Date: Sun, 13 Aug 2000 14:49:10 -0400
Source: Sound Digest Archive v02.n626
- -----Original Message-----
From: tube@jump.net <tube@jump.net>
To: Steve Van Osdell <svanos@queencity.com>
Cc: Joe List <sound@lists.io.com>
Date: Sunday, August 13, 2000 10:50 AM
Subject: Re: [JN] About WE247A tubes
>Steve,
>
>I think it's great that you are offering these tubes at low prices, and I
>assure
>you that no one wants to slam you personally. However, this is a VERY
>irreverent buch here, and if the opportunity to make a good joke appears,
>it is almost a certainty that someone will take that opportunity.
Yes. And, as other folks have observed, there is a lot of "love" on this
list. I've personally felt so loved sometimes that it hurts.
>
>I am puzzled the whole 12AX7 thing, however. My books say that the 247A
>is a higher mu version of the 244A, which in turn is a high quality 227
>(type 27).
>The 244A has a mu of 10, while the 247A has a mu of 15.
So, this would make the 247A a bit like a higher mu version of a???
anyone?... anyone?... To me the 247A seems like Western's version of a 76
(only, with a mesh plate). Or is it the other way around?
>
>Phil
>
>Steve Van Osdell wrote:
>
>> I recently posted a short message here regarding a couple of WE247A
>> tubes that I had on ebay (in case anyone was interested in them). I
>> had no idea of what they were worth except for one person's (who is very
>> knowledgeable in this hobby in general) opinion which was 'they ought to
>> be worth at least about $70 each'.
I would have to agree with this. WE 247As are rare and beautiful tubes. They
also sound quite nice. In my opinion, they are worth at least $70 each. If
they are NOS, they are worth more. I've had dealers pay more than $70 247As.
Generally, people only bitch about the high value of tubes like this when
they belong to someone else.
>>
>> So, it seems to me that if this estimate is wrong, someone would kindly
>> point it out to me in a helpful and friendly way rather than through a
>> negatively worded innuendo.
>>
>> Just today I am passing on some WE tubes to a few Joes at super good
>> prices because they are in need of them. I am not trying to get top
>> dollar from any 'Joe' for me tubes - it is just that some of them I
>> really don't know what they are worth.
No good deed goes unpunished.
>>
>> Thanks, Steve
>
=========================================================================
From: "Fred Volz" <fcv@emotiveaudio.com>
Subject: Re: [JN] I'm OUTTA HERE!
Date: Sun, 13 Aug 2000 15:25:02 -0400
Source: Sound Digest Archive v02.n626
- -----Original Message-----
From: Steve Van Osdell <svanos@queencity.com>
To: Joe List <sound@lists.io.com>
Date: Sunday, August 13, 2000 2:23 PM
Subject: [JN] I'm OUTTA HERE!
>I will be unsubscribing to the JoeList.
It's your call. But, do it for the right reasons.
(snip)
>However, very recent events have reminded me of things that disappointed
>me with this list back several years ago, and that is what I call the
>'ninnie' factor. There are a lot of nice and friendly guys on this
>list, but there are also a bunch of what I call 'ninnies'. These are
>people who, in my opinion, will complain about anything just to have
>something to complain about, or who will 'snipe' at someone less 'in the
>clic' than they are just for the fun of sniping.
Yup. I agree with this 100%. There are some folks on this list who spend a
fair bit of time basking in the warm and loving glow of brotherhood that
they feel this list supports. Just don't express any view that is not part
of their particular dogma. This is important, because we can all bask in the
glow and share in the brotherhood of free flowing ideas--as long as they are
the "right" ideas. But, if you smell like an outsider, everything you say or
do will be added to the list of reasons why you don't belong.
In other words, if a
>posting has absolutely nothing to do with them, or anything they might
>be interested in, they will take an opportunity to 'pick'.
Again true. Big ego, small penis.
>
>Just today, I received a private email from a prominent Joe which stated
>the following. I won't mention his name because it was sent privately.
>
>"You've only been back on the list for a few days, and you're again
>treating
>it as your little trading post. "How much is this worth?" was a
>constant
>refrain the last time you were subscribed, and now you're doing it
>again.
>People really don't like it, and you're seeing a little of the result.
>
>It's nice that you've got an amp built, and I'm sure people like to hear
>
>about it and stand ready to help on future projects, and there still is
>the
>occasional swapmeet posting here, but, please, give it a break."
It's important to ask yourself whether this "prominent" list member is
really speaking for the group. My guess is no. I've also had some
conversations with "prominent list members". From these, I've learned that
some of these people are leaders who command respect. Others just demand it.
On your swapmeet postings, I used to try to sell a few tubes on the list.
But, I finally decided that it was more fun to get lots more cash for them
from a dealer. And, the dealer never made me feel like a criminal for
requesting below market value for tubes. Now, if nice people on the list
want to get in touch with me for a certain tube, I'll do my best to help at
a fair price. But, the Small Penis Club can buy them for twice as much
somewhere else.
>So, if a guy is going to be 'lampooned and lambasted' for running a
>'little trading post' operation simply because he was doing some
>housecleaning and needed to sell a few things to pay for some new
>speakers (and was willing to give Joes a good deal on these things if
>they would be of use to anyone to boot), then this is NOT the place I
>need to be, and its NOT for me.
>
>I can communicate with the more friendlier guys I know on this list
>without being subscribed to the list anyway. There are some real
>peculiar types among us good guys here is all I have to say.
>
>Thank you very much
>Steve
>
Best wishes,
Fred Volz
fcv@emotiveaudio.com
=========================================================================
From: "Paul@13E1.com" <triode@bow-tie.org.uk>
Subject: Re: [JN] I'm OUTTA HERE!
Date: Sun, 13 Aug 2000 20:36:54 +0100
Source: Sound Digest Archive v02.n626
Dear Steve,
I must say that it seems a shame that you should wish to resign from the
list. Certainly I should like to distance my self from the private post you
received.
I think "How much is it worth?" is a perfectly reasonable question for the
list.
On the other hand I find it difficult to believe that you should take
offence at my joke about the oh-so-ubiquitous 12AX7, and yes the modest dig
about WE prices. Why not?
Paul de Raymond Leclercq
- --- Original Message -----
From: Steve Van Osdell <svanos@queencity.com>
To: Joe List <sound@lists.io.com>
Sent: Sunday, August 13, 2000 7:15 PM
Subject: [JN] I'm OUTTA HERE!
> I will be unsubscribing to the JoeList. I was away for some years and
> recently resubscribed back the first week of July. I made job changes
> and moved across the country during the time I was unsubscribed, and my
> audio hobby took a 'back seat'. So, now that I'm able to have the time
> to start giving it attention, I thought that I would resubscribe to this
> list.
>
> However, very recent events have reminded me of things that disappointed
> me with this list back several years ago, and that is what I call the
> 'ninnie' factor. There are a lot of nice and friendly guys on this
> list, but there are also a bunch of what I call 'ninnies'. These are
> people who, in my opinion, will complain about anything just to have
> something to complain about, or who will 'snipe' at someone less 'in the
> clic' than they are just for the fun of sniping. In other words, if a
> posting has absolutely nothing to do with them, or anything they might
> be interested in, they will take an opportunity to 'pick'.
>
> Just today, I received a private email from a prominent Joe which stated
> the following. I won't mention his name because it was sent privately.
>
> "You've only been back on the list for a few days, and you're again
> treating
> it as your little trading post. "How much is this worth?" was a
> constant
> refrain the last time you were subscribed, and now you're doing it
> again.
> People really don't like it, and you're seeing a little of the result.
>
> It's nice that you've got an amp built, and I'm sure people like to hear
>
> about it and stand ready to help on future projects, and there still is
> the
> occasional swapmeet posting here, but, please, give it a break."
>
> Now, I've done a search back thru my sent emails since I rejoined in
> July and here is a summation if what I found.
>
> 1. I sent and exchanged 4-5 emails discussing good choices for driver
> tubes and the possible sources for a 6C45pi. (nothing to do with
> 'trading post' issues here).
>
> 2. I posted a 1 or 2 messages about the RCA World's Fair Horn and asked
> if anyone had the skills to be able to duplicate one, and that if they
> did, I had an extra one they could use for making a mold. (nothing
> 'trading post' wise here)
>
> 3. Several postings responding to various little topics regarding
> favorite CD's, CD player recommendations, and questions regarding fixing
> the hum problem in my amp I built (nothing 'trading post' in these
> either).
>
> 4. Couple of postings recently mentioning that RatShack has dipole
> tweeters on sale for half price and asking if anyone had Andrej's email
> address (nothing trading post here).
>
> Then recently I bought some speakers and needed to do some housecleaning
> to sell a few things to help pay for them, so I posted some items in
> ebay and also dug out some old WE tubes I have (that most I have no idea
> what they do). So, I thought I'd see if anybody here might a. know if
> they were of any use, and b. if they were, offer them for sale here at a
> good price before listing them on ebay. I also mentioned about my
> Goodman woofers that I would sell also.
>
> So, if a guy is going to be 'lampooned and lambasted' for running a
> 'little trading post' operation simply because he was doing some
> housecleaning and needed to sell a few things to pay for some new
> speakers (and was willing to give Joes a good deal on these things if
> they would be of use to anyone to boot), then this is NOT the place I
> need to be, and its NOT for me.
>
> I can communicate with the more friendlier guys I know on this list
> without being subscribed to the list anyway. There are some real
> peculiar types among us good guys here is all I have to say.
>
> Thank you very much
> Steve
>
>
=========================================================================
From: "Hugh R Dean" <aspen@alphalink.com.au>
Subject: Re: [JN] I'm OUTTA HERE!
Date: Mon, 14 Aug 2000 09:21:32 +1000
Source: Sound Digest Archive v02.n626
Hi Steve, and other joes,
Can I please offer a few suggestions here Steve?
Firstly, you are valued on this list, and always active with tubes, and we
need guys like you.
Secondly, at any one time there are only a small number of contributors, for
whatever reason. But there is, as in all things in life I guess, a huge,
uncounted number of 'watchers on the cast iron balcony'. Although they are
not visible, they too learn, and they value your contribution, and not just
the IP, but the occasional fleamarket sale too.
Of those that are active, there is inevitably the usual spread of human
nature; some friendly, some sneering, some picky, some even nasty. That's
cool - that's life - we are surrounded in our private worlds by this
personality diversity - and even, I might suggest, within our own families.
Just live with it. If someone irks you, ignore it, If someone appeals,
send them an email expressing your approval. If someone has a trivial,
unthinking comment, smile, and move on.
And always be aware that very often someone who persecutes you is doing so
for their own reasons, and it is very likely no reflection on you at all.
Let's face it, it really doesn't matter too much what others think and say
to you; it really only matters what you think and say to yourself.
We all carry baggage. To get to the person, and their experience, you have
to go through the baggage checkout first. After all, no treasure trove
faces right onto the street. It's the nature of the beast.
I'd really like to see you continue your contributions to this august list.
I have made some wonderful friends here; hell, none of us would have met
Kurt if it wasn't for Joe Roberts selfless and continuous generosity....
Sincerely,
Hugh R. Dean
Melbourne, Australia
=========================================================================
From: "Paul Cambie" <cambie@ozemail.com.au>
Subject: Re: [JN] I'm OUTTA HERE!
Date: Mon, 14 Aug 2000 12:28:30 +1000
Source: Sound Digest Archive v02.n626
Hugh, what a marvellous post. I can recognise Steve's thoughts and
feelings, and Hugh, I think you spoke for us all in asking Steve to remain.
Few if any of us could have put it so well.
Cheers,
Paul
- ----- Original Message -----
From: Hugh R Dean <aspen@alphalink.com.au>
To: Joenet <sound@deliverator.io.com>
Sent: Monday, August 14, 2000 9:21 AM
Subject: Re: [JN] I'm OUTTA HERE!
> Hi Steve, and other joes,
>
>
> Can I please offer a few suggestions here Steve?
>
> Firstly, you are valued on this list, and always active with tubes, and we
> need guys like you.
>
> Secondly, at any one time there are only a small number of contributors,
for
> whatever reason. But there is, as in all things in life I guess, a huge,
> uncounted number of 'watchers on the cast iron balcony'. Although they
are
> not visible, they too learn, and they value your contribution, and not
just
> the IP, but the occasional fleamarket sale too.
>
> Of those that are active, there is inevitably the usual spread of human
> nature; some friendly, some sneering, some picky, some even nasty.
That's
> cool - that's life - we are surrounded in our private worlds by this
> personality diversity - and even, I might suggest, within our own
families.
>
> Just live with it. If someone irks you, ignore it, If someone appeals,
> send them an email expressing your approval. If someone has a trivial,
> unthinking comment, smile, and move on.
>
> And always be aware that very often someone who persecutes you is doing so
> for their own reasons, and it is very likely no reflection on you at all.
> Let's face it, it really doesn't matter too much what others think and say
> to you; it really only matters what you think and say to yourself.
>
> We all carry baggage. To get to the person, and their experience, you
have
> to go through the baggage checkout first. After all, no treasure trove
> faces right onto the street. It's the nature of the beast.
>
> I'd really like to see you continue your contributions to this august
list.
> I have made some wonderful friends here; hell, none of us would have met
> Kurt if it wasn't for Joe Roberts selfless and continuous generosity....
>
> Sincerely,
>
>
> Hugh R. Dean
> Melbourne, Australia
>
>
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: [JN] I'm OUTTA HERE!
Date: Sun, 13 Aug 2000 20:54:29 -0600
Source: Sound Digest Archive v02.n627
Hugh R Dean wrote:
> Hi Steve, and other joes,
SNIP of great stuff - see the original post
> After all, no treasure trove faces right onto the street.
SNIP
> Sincerely,
>
> Hugh R. Dean
> Melbourne, Australia
Speaking of great one-liners Hugh, I doubt that I'll ever forget this one
. . .
Steve, as far as the off-list niggling over trivia is concerned, just
like it wash right off your well-oiled duck's back . . just wash right off.
Usually it's not worth the time it takes to read, let alone get worked up
over.
Bill - PEARL, Inc.
=========================================================================
From: AnnaLogg@aol.com
Subject: Re: [JN] I'm OUTTA HERE!
Date: Sun, 13 Aug 2000 23:55:46 EDT
Source: Sound Digest Archive v02.n627
Well, I'm surprised I wasn't copied on that "private" note for letting my
favorite audio cyberpals know about the Technics turntable I found. And I
profusely apologize for my most recent post asking my panel of experts about
the Sennheiser mike -- a subject about which I know less than nothing.
Given these, I would think I deserve to go stand in the corner with Steve.
Move over, hon.
Anna :-(
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] I'm OUTTA HERE! - score one for brutality
Date: Sun, 13 Aug 2000 21:18:09 EDT
Source: Sound Digest Archive v02.n626
In a message dated 8/13/00 11:17:37 AM US Mountain Standard Time,
svanos@queencity.com writes:
(rcvd this privately...)
> People really don't like it
Oh, well. Seems anything that can send an E-mail considers itself people.
Royal plural, yet.
As if one cannot grow and learn about audio without kissing the nether parts
of some psychotic troll under the bridge, or, is it the gateway?
Good thing I am completely disabled and heavily medicated so I do not say
what I really think of "Miss Manners."
Happy Ears!
Al B^}
PS It wasn't my meds. The Sony direct to my Donkeyotee is lovely.
=========================================================================
From: "Dale Simon-contr" <Dale.Simon-contr@trw.com>
Subject: [JN] impedance and phase plots
Date: Tue, 06 Mar 2001 14:52:46 -0500
Source: Sound Digest Archive v02.n827
- --=_A9F23B1E.E180F138
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: quoted-printable
does anyone have a phase and impedance plot for a typical bass driver that =
they could send me. I'm interested in the affects on phase in and around =
the resonant frequencies. I don't have web access right now, or I would =
search one out.
thanks,=20
Dale Simon
Phone: 527-223-6919
E-mail : dale.simon-contr@trw.com
- --=_A9F23B1E.E180F138
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; charset=3Diso-8859-1"=
>
<META content=3D"MSHTML 5.50.4522.1800" name=3DGENERATOR></HEAD>
<BODY style=3D"MARGIN-TOP: 2px; FONT: 10pt Arial; MARGIN-LEFT: 2px"=20
bgColor=3D#ffffff>
<DIV>does anyone have a phase and impedance plot for a typical bass driver =
that=20
they could send me. I'm interested in the affects on phase in and =
around=20
the resonant frequencies. I don't have web access right now, or I =
would=20
search one out.</DIV>
<DIV>thanks, </DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>Dale Simon<BR>Phone: 527-223-6919<BR>E-mail : <A=20
href=3D"mailto:dale.simon-contr@trw.com">dale.simon-contr@trw.com</A></DIV>=
</BODY></HTML>
- --=_A9F23B1E.E180F138--
=========================================================================
From: David Home <David_Home@creoscitex.com>
Subject: [JN] Impedance matching to line-amp output tranny
Date: Tue, 31 Oct 2000 15:28:38 +0100
Source: Sound Digest Archive v02.n712
Hello all.
I am confused about the best way to match a plate resistance to the primary of an air-gapped 15K:60
0 ohm transformer.
Is it best to think of this like an interstage transformer where the best will be with 15K on the pr
imary and 600 ohm on the secondary?
Or is this like an output tube tranny where the primary should be 2~3 times the plate resistance of
the tube?
Regards, David
=========================================================================
From: Dan Marshall <mdaniel7@uswest.net>
Subject: Re: [JN] Impedance matching to line-amp output tranny
Date: Tue, 31 Oct 2000 11:05:43 +0000
Source: Sound Digest Archive v02.n713
Hi David,
My take on this subject is that there is a considerable variation in ITs
and oft times the rated impedance means little. This is especially true
of the less expensive units. I would bench test them using a squarewave
generator with a pot (say, 25k - $50k, or thereabouts) in series with
the generator. It would perhaps be advisable to connect an interconnect
cable to the output, so its capacitance can be included. Vary the pot
resistance and see whether you can achieve good squarewave response. If
so, check the frequence response on both ends of the spectrum to see
whether it is adequate, say, essentially flat from 20 Hz to 20 kHz. If
successful, select a tube with an rp as close as possible to the
combined resistance of the pot and generator output impedance, or
perhaps tweak it a little by playing about with a portion of the cathode
resistor unbypassed, i.e., if the value is relatively critical for the
particular unit. If it is a good IT the precise impedance value will
not be as critical.
Failing success with the above, connect a suitable pot across the
secondary and determine whether you can vary the load and improve the
situation. For a given source resistance you likely will find that
there is a optimum secondary load value. Better quality IT tend to work
better with no secondary load than do cheapies. Lowering the source
resistance will extend both the low end and the high end, generally with
worse HF ringing characteristics. Actually, as the pot value is reduced
the bandwidth will improve up to a point, then further lowering of the
source impedance will cause HF ringing to become problematic.
Conversely, too high a load will cause less low and high end extension.
In general, try to keep the secondary loading as low as possible and
concentrate first on optimizing the primary driving impedance,
consistent with attaining adequate bandwidth. Its all a balancing act.
If you luck out you may find an optimum primary driving impedance that
will provide good squarewave response and adequate bandwidth with no
secondary load. If not, then you will have to optimize them as best you
can, consistent with keeping the secondary loading as low as possible,
i.e., the load value as high as possible. You may not want to overly
concern yourself with ringing well above the top end of the audio band.
Some ITs will ring at the upper end of the audio band, or just beyond,
in which case the transformer will exhibit a rising characteristic on
the top end of the audio band. A few will ring within the audio band.
Such units may not be optimizable for full range usage. The only way I
was able to tame one pair of SE to PP grids transformers was to parallel
the secondaries and use them as the primary (for SE). It still
exhibited a slight rising characteristic at 20 kHz with no secondary
loaded. Fortunately, it was just about the right amount to compensate
for the rolloff of the big Hammond opt. Used in the normal manner they
exhibited severe ringing around 10 kHz, no matter what the source
impedance. Connected as outlined above they had a broad and relatively
mild resonance at 28 kHz, with the secondary unloaded. If not reversed
(with secondaries paralleled), they were rolled off at 20 kHz, no matter
how they were driven. So, as you can see, there are no hard and fast
rules for ITs, you have to roll the dice and then work with (optimize)
what you have.
Dan Marshall
David Home wrote:
>
> Hi Simon. Thanks for the reply.
> I do not understand your answer though. What do you mean by light loading?
> Purhaps I am not being clear. Are line driver transformers like this designed to run with the impe
dances on the windings as close to the listing as possible? ( In my case, a plate resistance of 15K
on the primary and the secondary terminated with a 600 ohm load)
> I think with ITs it seems to be important. For example, Lundahl warns that too high a load will li
mit frequency response. Too low a load will cause ringing.
> Regards, David
>
> -----Original Message-----
> From: Simon Busbridge [mailto:S.C.Busbridge@bton.ac.uk]
> Sent: Tuesday, October 31, 2000 4:12 PM
> To: David Home
> Cc: sound@lists.io.com
> Subject: Re: [JN] Impedance matching to line-amp output tranny
>
> David,
>
> I may be wrong about this, but I would prefer to run the valve with as
> light a load as possible, so that it sees constant current. If the
> transformer has some high frequency nasties, it maybe that the secondary
> needs loading a little, but it is the signal voltage that is transferred
> at line level without the need to transfer signal power.
>
> Simon
>
> Simon Busbridge, BSc(Hons) PhD CPhys MInstP
> School of Engineering
> University of Brighton
> Lewes Road
> Moulsecoomb
> Brighton BN2 4GJ
> UNITED KINGDOM
>
> Tel: 0044 (0)1273 642542
> Fax: 0044 (0)1273 642327/642301
> e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com
>
> On Tue, 31 Oct 2000, David Home wrote:
>
> > Hello all.
> > I am confused about the best way to match a plate resistance to the primary of an air-gapped 15
K:600 ohm transformer.
> > Is it best to think of this like an interstage transformer where the best will be with 15K on th
e primary and 600 ohm on the secondary?
> > Or is this like an output tube tranny where the primary should be 2~3 times the plate resistance
of the tube?
> > Regards, David
> >
=========================================================================
From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
Subject: Re: [JN] Impedance matching to line-amp output tranny
Date: Tue, 31 Oct 2000 15:11:48 +0000 (GMT)
Source: Sound Digest Archive v02.n713
David,
I may be wrong about this, but I would prefer to run the valve with as
light a load as possible, so that it sees constant current. If the
transformer has some high frequency nastie