Sound Practices Mailing List Files - Volume 2
=========================================================================
From: "Greg Monfort" <wingracer@email.msn.com>
Subject: "100+dB / 1W speaker". Was: Fw: [JN] System 1:Step 4, Speakers...........
Date: Fri, 11 Feb 2000 14:10:19 -0500
Source: Sound Digest Archive v02.n445
Hi,
I guess I should have changed the subject line to: "100+dB / 1W speaker". I
was 'thinking out loud' so to speak WRT Peter's desire for a 1W ~full range
speaker. I couldn't sleep and found it an interesting diversion.
WRT the System 1, I'm for a two way horn system down to ~100Hz, with a
multiple driver bass unit to keep the size semi-reasonable, but after
witnessing the BassList Speaker design forum / fiasco I'm steering clear of
this one too. :^))
- -------------
Jean-Michel Le Cleac'h wrote:
>
> While necessary, frequency response and cut-off slope are not the only
> things to consider.
========
You bet! Amplitude, phase shift, etc.
========
> How is the impedance inside the reproduced interval of frequency? is
> another important question.
========
Why so in a wide range driver?
========
> Also a TEF to look for possible parasitic resonnances (inside the air
> volume between basket and membrane, inside the basket,etc.) is necessary.
========
This is well beyond my capabilities at present, and normally isn't
considered in most DIY, but would be nice.
========
> IMHO our Joenet's loudspeakers system should present a constant impedance
> from 100Hz to 10000Hz.
========
I'm not sure why, with my idea at least, but a zobel should take care of it.
- -------------
Gordon wrote:
> Actually if you had the T/S parameters for this you would know that it
> would be more like 0.7CUf and tuned to 125 is about as low as you can go.
========
Again, if the info at
http://www.netspace.or.jp/~eifl/eifl/export/export2.htm
is fairly accurate, Vas Qes, Qms can be guesstimated from it's Qts,
Sensitivity ratings. With my assumptions, BoxPlot predicted close enough to
your numbers for a Q =.7 box, but that's hardly all the BW this puppy can
do, or any other driver for that matter.
With a power limited EBS (extended bass shelf) alignment (and <2W is pretty
limited IMO!) there's lots more usable BW to be had, especially when a
second driver of the same type is added to help fill in the bottom octaves.
A little room gain helps to finish it off.
An EBS also lowers system Q, reduces phase shift, and gives a ~flat
amplitude response over a wider BW (with a second driver). It's my
understanding, and experience, that these are all pluses in the pursuit of
accurate sound reproduction.
Tradeoffs are dramatically increased box size, non flat FR, though in this
design I see neither one being an issue.
TIA for more insight,
GM
=========================================================================
From: "Le Cleac'h Jean-Michel" <lecleach@paris.ensmp.fr>
Subject: Re: [JN] 100 mu.sec. square wave - RIAA filtered
Date: Thu, 16 Nov 2000 18:35:32 +0100
Source: Sound Digest Archive v02.n735
This is a multi-part message in MIME format.
- ------=_NextPart_000_000F_01C04FFC.0048D560
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Hello,
As since several days it is very difficult to use xdrive from France, I send
to the whole list a very small attachment (4.71k) that contains a 2 color
.gif graph showing a part of a square signal through an inverse RIAA
network (the one I described previously).
I could have shown the result of a longer duration square signal but in fact
it only differs by the length of the nearly horizontal part of the signal,
so you can easily prolongate linearly the actual signal to obtain a longer
one.
Best regards,
Jean-Michel Le Cleac'h, Paris, France
- ------=_NextPart_000_000F_01C04FFC.0048D560
Content-Type: image/gif;
name="Sq100musec RIAA.gif"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
filename="Sq100musec RIAA.gif"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- ------=_NextPart_000_000F_01C04FFC.0048D560--
=========================================================================
From: j45yip@netscape.net (Johari Yip)
Subject: [JN] 100W AKSA Amp
Date: Fri, 24 Aug 2001 11:05:48 -0400
Source: Sound Digest Archive v02.n954
Hi all,
Wondering if anyone on the list has already own one. How does it match up to the 55 watter?
- --
Johari Yip
===================
j45yip@netscape.net
===================
__________________________________________________________________
Your favorite stores, helpful shopping tools and great gift ideas. Experience the convenience of buy
ing online with Shop@Netscape! http://shopnow.netscape.com/
Get your own FREE, personal Netscape Mail account today at http://webmail.netscape.com/
=========================================================================
From: Larry Van Wormer <lvw@bmts.com>
Subject: [JN] $10 CDnow coupon Expires 2/15
Date: Wed, 10 Feb 1999 20:45:37 -0500
Source: Sound Digest Archive v02.n040
http://www.cdnow.com/cgi-bin/mserver/redirect/leaf=from=vbd:u:imu:nht:d
A nice deal, $10 off an order of $20 or more. I just ordered a couple of
CD's using it.
Larry Van Wormer
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: [JN] 10" driver recommendation?
Date: Fri, 23 Apr 1999 04:37:05 -0400
Source: Sound Digest Archive v02.n130
Lady and Gents,
Following a failed commercial venture, a good friend has a
pair of impressive looking (and very expensive) 70 liter speaker boxes
needing a suitable full range/coaxial 10 inch driver, hopefully of highish
dB/watt sensitivity.
I have suggested the Tannoy 10" coaxial, going on the 12's and 15's I have
heard and liked very much. But I have never heard them.
Any ear reports on the 10", or any other suggestion?
The boxes are currently sealed, but a reflex port could easily be fitted,
conversion to a horn (front or rear) is not possible...
The box design will not allow a separate tweeter and still look as stunning
as it does, hence the full range/coax request.
Thanks in advance for any experiences/suggestions. A European sourced
device would be preferred but is not essential.
Allen (VSE)
PS We have a REAL web address now:
www.vacuumstate.com
=========================================================================
From: "=?ISO-8859-1?Q?Torbj=F8rn_Lien?=" <mdrivekl@online.no>
Subject: Re: [JN] 10" driver recommendation?
Date: Fri, 23 Apr 1999 20:06:43 +0200
Source: Sound Digest Archive v02.n130
Hello Allen, all,-
Allen Wright wrote:
> Lady and Gents,
> Following a failed commercial venture, a good friend has
> a pair of impressive looking (and very expensive) 70 liter
> speaker boxes needing a suitable full range/coaxial 10 inch
> driver, hopefully of highish dB/watt sensitivity.
>
> I have suggested the Tannoy 10" coaxial, going on the 12's
> and 15's I have heard and liked very much.
[snip!]
I don't get to post or participate much these days,-(The family
+ I is moving to a new appartment,-so I'm buried in my junk and
stash these days, trying to sort through it.....(wondering what
evil childhood experiences that made me collect all this junk..)
But,-amongst that is a pair of the 10" 'er Goodmans axiom 80.
(Mine are not for sale..Took me 10 years to get an old pair..)
IMNHO this is easily the most well-balanced, musical and extended
full-range driver I've yet experienced,-
I think it beats the Lowther-consept clearly,-when it comes to balance,
versatility,finesse,-especially on vocal.But they are
*somewhat* thin in the bass,-Not much there as the cantilever
surround makes for an extremely low Fres ,-with a following
very lo-Q.
If they still are made I don't know,- but Godmans produced a
series for the Asian marked in the mid/late eighties I think.
At that time it was possible to get these in Denmark,-
for approx. 2400 Dkr. each? (Kurt?)
Maybe other know something on the wherabouts of the
Axiom 80's these days?
My 2 oeres worth. (100 oere=1 Nok= 0,128 USD)
Regards
Torbjoern Lien,
Norway
>
>
>
>
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: Re: [JN] 10" driver recommendation?
Date: Sun, 25 Apr 1999 07:20:28 -0400
Source: Sound Digest Archive v02.n131
Torbjoern wrote:
>>>But,-amongst that is a pair of the 10" 'er Goodmans axiom 80.
(Mine are not for sale..Took me 10 years to get an old pair..)
IMNHO this is easily the most well-balanced, musical and extended
full-range driver I've yet experienced,- I think it beats the
Lowther-consept clearly<<<
I know them well, and almost had a pair for myself - but the seller pulled
out of the deal when he found what these puppies are worth in Japan!
They do sound beautiful but would be far too fragile for my friends usage,
he tends to play things loud. Great suggestion though!
Allen (VSE)
PS Anyone heard a Tannoy 10" coax?
=========================================================================
From: Torsten.Loesch@enhar-ha.nthames.nhs.uk
Subject: Re(2): [JN] 10" driver recommendation?
Date: 26 Apr 1999 11:15:32 +0000
Source: Sound Digest Archive v02.n131
Hi there,
Allen (VSE) wrote:
> PS Anyone heard a Tannoy 10" coax?
I have (fairly regulary actually) heard the Tannoy 10" Units for
Studio-use.... Reasonably nice, but not great....
How about trying these Boxes with a Normal decent Wideband 10" (JBL 2123?)
and a Horn sitting on top of them.... I know - boring, but works well....
Later Thorsten
=========================================================================
From: "Craig Anderson" <craigha@home.com>
Subject: Re: [JN] 10k:10k input tranny?
Date: Fri, 31 Aug 2001 21:42:19 -0600
Source: Sound Digest Archive v02.n958
Funny you should ask, I placed an order for one
of these today:
WSM 10k/10k
0.5 Watt Matching Transformer
10k ohms to 10k ohms
http://www.edcorusa.com/magnetics/audio/WSM/WSM10k-10k.htm
$7.56
My first purchase here, they have an 800 order line and sold me qty 1.
I'm planning to build a single channel headphone amp and try one of these
for a stereo to mono input.
EM6410
Stereo to Mono Coupling Transformer
Stereo line level to mono line level
$7.09
- ----- Original Message -----
From: "Steven S" <steven@403forbidden.net>
To: <sound@lists.io.com>
Sent: Friday, August 31, 2001 8:38 PM
Subject: [JN] 10k:10k input tranny?
>
> Anyone know where i can get a small and/or good 10k:10k input
> tranny. Putting together a headphone amp to fiddle with and i cant seem to
> find what i'm looking for from the usual sources.
>
>
>
> Steven St.Laurent ::: stevensl@mindspring.net ::: 403forbidden.net
>
> "Outlook not so good."
> That magic 8-ball knows everything!
> I'll ask about Exchange Server next.
>
>
>
=========================================================================
From: Steven S <steven@403forbidden.net>
Subject: [JN] 10k:10k input tranny?
Date: Fri, 31 Aug 2001 22:38:35 -0400 (EDT)
Source: Sound Digest Archive v02.n958
Anyone know where i can get a small and/or good 10k:10k input
tranny. Putting together a headphone amp to fiddle with and i cant seem to
find what i'm looking for from the usual sources.
Steven St.Laurent ::: stevensl@mindspring.net ::: 403forbidden.net
"Outlook not so good."
That magic 8-ball knows everything!
I'll ask about Exchange Server next.
=========================================================================
From: "Ellen Oler" <ellenoler@earthlink.net>
Subject: [JN] 10 monkeys eat a free lunch
Date: Sun, 05 Nov 2000 22:09:16 -0500
Source: Sound Digest Archive v02.n722
I *think* that what would happen is that they would reach an equilibrium
somewhere. You couldn't hold either tube to a fixed op point as if it were
attached to a stiff supply, you could just get it set to a desired op point
by experimentation, I imagine.
Imagine using one of the Doc B C4S boards set to 30mA instead of another
tube. Well, the tube attached to the C4S would reach an equilibrium where it
was drawing the current it was permitted to draw - the DC op point would be
forced to shift - I think??? With the two tubes I imagine the voltage drop
across each one would shift (from where it would be otherwise in a "free
running" setup) until they were both working at the same current.
What this does to the sound of course is anybody's guess. In fact the whole
thing is just a guess . . .
I bet as you twiddled that 300 ohm pot you'd get the cathode of the 10
running up and down to adjust. Sounds like a fun sport!
- -j, voting for Al (M.? G.?) in a couple of days, then breathlessly awaiting
the Canadian results
>what happens if one of the tubes is not matched in current draw to the other?
>
>in otherwords, if the 10 is running 30ma and the 6c45 is biased to run
>35ma??? or take it the other way and let the 10 run 35ma and the russkie
>only lets 30ma go through...
>
>well we know both tubes will have the same current, the question becomes is
>that how much current they would be running if the other tube were not
>there?
>
>its an interesting question, what happens to a tube when you force it away
>from its characteristics? can this be done...
>
>i bet a small say 300 ohm or so pot in series with the choke will let you
>tune the sound and nail the operating point... and a 500 ohm DCR choke is
>easy enough to source for this... otherwise you got 6500 turns of #35 on an
>EI87 nickel core....
>
>in any event at some point one of the tubes is gonna current limit the
>other...
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: [JN] 10 monkeys eat a free lunch - design idea/questions
Date: Fri, 3 Nov 2000 10:16:03 -0500
Source: Sound Digest Archive v02.n720
Design idea:
Monkey amp using 10 tube driven by 6C45Pi. Both run at 35mA, so no need for
a seperate cathode resistor from the cathode of the 10 to ground: all the
10's juice flows through the driver tube.
Design questions:
Does there need to be a bypass cap from the cathode of the 10 to prevent
regeneration? As I look at it, the driver tube would serve as a cathode
impedance for the 10 equal to the vector sum of the impedance of the driver
load choke plus the plate impedance of the driver tube plus any resistance
needed in series to get correct bias (does some portion of this get
multiplied by the mu of the bottom tube too?) hence the 10 would suffer a
large amount of regenerative feedback. True or false?
Also as I see it, the bypass could either go from cathode to B+ a la
Ultrapath or cathode to ground as is more conventionally done. True or false
or not necessary because the first answer is "false"?
If the bypass cap is necessary would it need to be largish (because the
total cathode impedance is smallish, say <2K) or small (because there is in
fact a "times mu" term that makes the effective impedance large)?
Proposed schematic for reference:
(fixed width font please):
B+
|
C|C--->
C|C
C|C--->
|
10 _|_
...-----+
/^\ |
| | |
UUU |
bypass?----* | (* = center tap of filament
< | transformer)
DCR < |
of this < |
R and | |
choke C| |
totals C| |
~860 C| |
+------+
6C45Pi _|_
- -----+-----...
C| --,
C| |
C| _|_
C| -
| | 2 x AA battery
V _|_
-
|
V
Note that this could be built as a one-resistor per channel amp (grid
stopper on 6C45pi), if a battery is used to bias the driver and the plate
choke DCR is made 860 ohms, and a grid choke is used on the input.
Figure a filtered supply of 595 V, drop 5V in the OPT, drop 395 across the
10, drop 30 (DCR = 860, I = 35mA) to the plate of the 6C45Pi where the
voltage will be 165V. (I got this 10 op point from a Joe who oughta know.)
- -j
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] 10 monkeys eat a free lunch - design idea/questions
Date: Fri, 3 Nov 2000 11:20:09 EST
Source: Sound Digest Archive v02.n720
- --part1_db.bbbb1b8.27343fb9_boundary
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Hi
If you replace the two AA batterries with a 6AS7 with its grip tied to the
plate (as a diode), you can live without the bypass C.
In my amp, the 6AS7 so wired drops 4.4 volts at 40 mA, so it will be fairly
close at 35 mA.
Happy Ears!
Al B^}
- --part1_db.bbbb1b8.27343fb9_boundary
Content-Type: text/html; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
<HTML><BODY BGCOLOR="#ffffff"><FONT SIZE=2>Hi
<BR>
<BR>If you replace the two AA batterries with a 6AS7 with its grip tied to the <BR>plate (as a diode
), you can live without the bypass C.
<BR>
<BR>In my amp, the 6AS7 so wired drops 4.4 volts at 40 mA, so it will be fairly <BR>close at 35 mA.
<BR>
<BR>Happy Ears!
<BR>Al B^}
<BR>
<BR></FONT></HTML>
- --part1_db.bbbb1b8.27343fb9_boundary--
=========================================================================
From: "Epstein, Jeremy" <JEpstein@ndbcap.com>
Subject: RE: [JN] 10 monkeys eat a free lunch - design idea/questions
Date: Fri, 3 Nov 2000 12:06:43 -0500
Source: Sound Digest Archive v02.n720
> Hi Jeremy,
>
> wow, a tube related technical question on the JoeNet,
> long time no see.
Sorry.
DEMOCRACY SUCKS!! UP WITH IMPERIALISM!! JUST BECAUSE YOU'RE PARANOID DOESN'T
MEAN THEY'RE *NOT* OUT TO GET YA!! SEX PISTOLS RULE!!
Better?
> >Monkey amp using 10 tube driven by 6C45Pi. Both run at 35mA,
> so no need for
> >a seperate cathode resistor from the cathode of the 10 to
> ground: all the
> >10's juice flows through the driver tube.
>
> Sounds like a nice idea!
I got some VT-25's for my birthday, hence the thought.
> >Does there need to be a bypass cap from the cathode of the
> 10 to prevent
> >regeneration?
>
> Absolutely. You will get no output signal from this amp
> without a cathode bypass.
OK.
> >If the bypass cap is necessary would it need to be largish
> (because the
> >total cathode impedance is smallish, say <2K)
>
> If memory serves me right then the impedance seen when
> looking into the cathode is (Rp+Ra)/(mu+1).
> The size of bypass cap needed will a bit less then in a conventional
> cathode biased stage but not by much so.
So pretty large the way I like to do it, say 100uF or thereabouts.
> I hope the AA-batteries you mentioned in your schematic consists
> of NiCd cells. Normal batteries will blow up!
But of course! Anecdotal research shows that NiCads will survive 70mA of
charging current for at least many months.
Thanks Manfred!
- -j
=========================================
Jeremy Epstein........jepstein@ndbcap.com
=========================================
=========================================================================
From: "Larry D. Moore" <l-moore@onu.edu>
Subject: Re: [JN] 10 monkeys eat a free lunch - design idea/questions
Date: Fri, 03 Nov 2000 12:33:30 -0500
Source: Sound Digest Archive v02.n720
Don't like monkey amps. Tried it. It simply moves the problem from one
location in the circuit to another. Think making the cathode bypass cap
the most critical component in the amp signal section. To me, do seperate
supplies, diode bridge, or a cap. I mean I'd rather pick a low value cap
that sounds good than a big one that sounds bad. Think 0.1uF versus
several orders of magnitude bigger. Granted it will change the soundstage,
but if you listen long enough it is simply wrong.
LDM
At 10:16 AM 11/3/00 -0500, you wrote:
>Design idea:
>
>Monkey amp using 10 tube driven by 6C45Pi. Both run at 35mA, so no need for
>a seperate cathode resistor from the cathode of the 10 to ground: all the
>10's juice flows through the driver tube.
>
>Design questions:
>
>Does there need to be a bypass cap from the cathode of the 10 to prevent
>regeneration? As I look at it, the driver tube would serve as a cathode
>impedance for the 10 equal to the vector sum of the impedance of the driver
>load choke plus the plate impedance of the driver tube plus any resistance
>needed in series to get correct bias (does some portion of this get
>multiplied by the mu of the bottom tube too?) hence the 10 would suffer a
>large amount of regenerative feedback. True or false?
>
>Also as I see it, the bypass could either go from cathode to B+ a la
>Ultrapath or cathode to ground as is more conventionally done. True or false
>or not necessary because the first answer is "false"?
>
>If the bypass cap is necessary would it need to be largish (because the
>total cathode impedance is smallish, say <2K) or small (because there is in
>fact a "times mu" term that makes the effective impedance large)?
>
>
>Proposed schematic for reference:
>
>(fixed width font please):
>
>
> B+
> |
> C|C--->
> C|C
> C|C--->
> |
> 10 _|_
> ...-----+
> /^\ |
> | | |
> UUU |
> bypass?----* | (* = center tap of filament
> < | transformer)
> DCR < |
> of this < |
> R and | |
> choke C| |
> totals C| |
> ~860 C| |
> +------+
> 6C45Pi _|_
>-----+-----...
> C| --,
> C| |
> C| _|_
> C| -
> | | 2 x AA battery
> V _|_
> -
> |
> V
>
>
>Note that this could be built as a one-resistor per channel amp (grid
>stopper on 6C45pi), if a battery is used to bias the driver and the plate
>choke DCR is made 860 ohms, and a grid choke is used on the input.
>
>Figure a filtered supply of 595 V, drop 5V in the OPT, drop 395 across the
>10, drop 30 (DCR = 860, I = 35mA) to the plate of the 6C45Pi where the
>voltage will be 165V. (I got this 10 op point from a Joe who oughta know.)
>
>-j
>
>=========================================
>Jeremy Epstein........jepstein@ndbcap.com
>=========================================
>
>
=========================================================================
From: MHuber@t-online.de (Manfred Huber)
Subject: Re: [JN] 10 monkeys eat a free lunch - design idea/questions
Date: Fri, 03 Nov 2000 17:48:52 +0100
Source: Sound Digest Archive v02.n720
Hi Jeremy,
wow, a tube related technical question on the JoeNet,
long time no see.
>Monkey amp using 10 tube driven by 6C45Pi. Both run at 35mA, so no need for
>a seperate cathode resistor from the cathode of the 10 to ground: all the
>10's juice flows through the driver tube.
Sounds like a nice idea!
>Does there need to be a bypass cap from the cathode of the 10 to prevent
>regeneration?
Absolutely. You will get no output signal from this amp without a cathode bypass.
Imagine you sit in the #10 and lock out through the cathode wire. What do
you see first? The choke! This means there is a very large ac impedance
in between the cathode and GND.
The other way around: Imagine a signal on the plate of the 6C45.
This signal is also on the grid of the #10. Because of the choke there
is no ac current through the tubes and the #10 cathode will follow it's grid!
Viewed from this perspective it looks like a 'choke-enhanced' SRPP stage.
The bypass cap 'shorts' the #10 cathode to gnd and thus allows the #10
to modulate it's plate current.
>As I look at it, the driver tube would serve as a cathode
>impedance for the 10 equal to the vector sum of the impedance of the driver
>load choke plus the plate impedance of the driver tube plus any resistance
>needed in series to get correct bias (does some portion of this get
>multiplied by the mu of the bottom tube too?) hence the 10 would suffer a
>large amount of regenerative feedback. True or false?
Exactly true!
>Also as I see it, the bypass could either go from cathode to B+ a la
>Ultrapath or cathode to ground as is more conventionally done. True or false
True.
>If the bypass cap is necessary would it need to be largish (because the
>total cathode impedance is smallish, say <2K)
If memory serves me right then the impedance seen when
looking into the cathode is (Rp+Ra)/(mu+1).
The size of bypass cap needed will a bit less then in a conventional
cathode biased stage but not by much so.
I hope the AA-batteries you mentioned in your schematic consists
of NiCd cells. Normal batteries will blow up!
Regards
Manfred
- ------------------
Manfred Huber
MHuber@t-online.de
- ------------------
=========================================================================
From: dslagle@earthlink.net (dave slagle)
Subject: Re: [JN] 10 monkeys eat a free lunch - design idea/questions
Date: Fri, 3 Nov 2000 13:31:43 -0500
Source: Sound Digest Archive v02.n721
hey j,
what happens if one of the tubes is not matched in current draw to the other?
in otherwords, if the 10 is running 30ma and the 6c45 is biased to run
35ma??? or take it the other way and let the 10 run 35ma and the russkie
only lets 30ma go through...
well we know both tubes will have the same current, the question becomes is
that how much current they would be running if the other tube were not
there?
its an interesting question, what happens to a tube when you force it away
from its characteristics? can this be done...
i bet a small say 300 ohm or so pot in series with the choke will let you
tune the sound and nail the operating point... and a 500 ohm DCR choke is
easy enough to source for this... otherwise you got 6500 turns of #35 on an
EI87 nickel core....
in any event at some point one of the tubes is gonna current limit the
other... i would be interested to hear what the tone "pot" does to the
sound... and who knows... maybe it will all just fall perfectly into
place... tubes have a funny way of doing that.
dave
>>
>>
>> B+
>> |
>> C|C--->
>> C|C
>> C|C--->
>> |
>> 10 _|_
>> ...-----+
>> /^\ |
>> | | |
>> UUU |
>> bypass?----* | (* = center tap of filament
>> < | transformer)
>> DCR < |
>> of this < |
>> R and | |
>> choke C| |
>> totals C| |
>> ~860 C| |
>> +------+
>> 6C45Pi _|_
>>-----+-----...
>> C| --,
>> C| |
>> C| _|_
>> C| -
>> | | 2 x AA battery
>> V _|_
>> -
>> |
>> V
>>
>>
=========================================================================
From: Paul Joppa <pdjoppa@home.com>
Subject: Re: [JN] 10 monkeys eat a free lunch - design idea/questions
Date: Fri, 03 Nov 2000 17:41:03 -0800
Source: Sound Digest Archive v02.n721
> From: "Epstein, Jeremy"
> Design idea:
>
> Monkey amp using 10 tube driven by 6C45Pi. Both run at 35mA, so no need for
> a seperate cathode resistor from the cathode of the 10 to ground: all the
> 10's juice flows through the driver tube.
>
> Design questions:
>
> Does there need to be a bypass cap from the cathode of the 10 to prevent
> regeneration?
As long as the output signal current goes through the cathode circuit to
ground (then through the power supply back to the output transformer and
tube), it needs to be bypassed. With parallel feed or ultrapath, the
signal current in the midband can be kept out of the cathode to ground
path and the bypass cap is not needed. I have talked briefly with two
people who have tried parafeed with and without the cathode bypass cap;
both thought it sounded better (had better bass) with the cap. It might
have worked better if the parafeed/ultrapath cap were as large as a
bypass cap, like 220uF instead of 2.2uF. I have not heard from anyone
who has tried this yet though - I say, go for it, Jeremy! and tell us
what happened...
Another way to look at it - without a bypass it is a mu follower of the
amplified choke variety (an SRPP with a choke for the upper bias
resistor). This is a great driver circuit, with output taken from the
lower plate. Or, take it from the upper cathode as a cathode follower
output, cap coupled to an interleaved output transformer. Kind of a
mutant spud...
> If the bypass cap is necessary would it need to be largish (because the
> total cathode impedance is smallish, say <2K) or small (because there is in
> fact a "times mu" term that makes the effective impedance large)?
Like any other cathode bypass cap, it should be large enough to have a
small impedance relative to the rest of the output signal current loop.
In addition, if the cathode impedance is to be kept small enough to not
affect the 10's operation, the cathode impedance should be small
relative to the 10's cathode impedance which is on the order of 1/gm.
> Note that this could be built as a one-resistor per channel amp (grid
> stopper on 6C45pi), if a battery is used to bias the driver and the plate
> choke DCR is made 860 ohms, and a grid choke is used on the input.
So use a ferrite bead on that grid! :^)
- -Paul Joppa
=========================================================================
From: Rich Conte <rconte@attglobal.net>
Subject: [JN] 10 Tube, VT25 DC Coupled driven by 6sn7
Date: Fri, 09 Feb 2001 21:24:41 -0500
Source: Sound Digest Archive v02.n802
Dear Folks,
I just installed 2 - 10's running only 6.3 V AC Filament supply v. req.
7.5 and do they ever sound good, just DC coupled
via 6SN7's, rectifier is GZ37 and outputs are NOS.
Anyone use these, they are the BRIGHTEST filaments I've seen, look like
Svetlana Triodes.
The tubes GE VT25 and RCA VT25...even at 5.0 V AC they are wonderful.
The plates run about 305VDC and current about 20mA.
Cheers,.
=========================================================================
From: SBench@aol.com
Subject: Re: [JN] 10 Tube, VT25 DC Coupled driven by 6sn7
Date: Fri, 9 Feb 2001 21:46:59 EST
Source: Sound Digest Archive v02.n803
In a message dated 01-02-09 21:28:51 EST, rconte@attglobal.net writes:
> I just installed 2 - 10's running only 6.3 V AC Filament supply v. req.
> 7.5 and do they ever sound good, just DC coupled
> via 6SN7's, rectifier is GZ37 and outputs are NOS.
>
> Anyone use these, they are the BRIGHTEST filaments I've seen, look like
> Svetlana Triodes.
>
> The tubes GE VT25 and RCA VT25...even at 5.0 V AC they are wonderful.
>
> The plates run about 305VDC and current about 20mA.
>
I can confirm that 801s (which oughta be similar) sound great at
that operating point (300V, 20mA and 6.3V on the filaments).
- -Steve
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 10 Tube, VT25 DC Coupled driven by 6sn7
Date: Sat, 10 Feb 2001 12:49:30 +0100
Source: Sound Digest Archive v02.n803
Guys
Arent these tubes supposed to run on 7.5 V ?
lowering heater voltage will decrease life expectancy......
Enjoy your sound (a little longer :-)
Guido
At 21:46 9-2-01 -0500, SBench@aol.com wrote:
>In a message dated 01-02-09 21:28:51 EST, rconte@attglobal.net writes:
>
>> I just installed 2 - 10's running only 6.3 V AC Filament supply v. req.
>> 7.5 and do they ever sound good, just DC coupled
>> via 6SN7's, rectifier is GZ37 and outputs are NOS.
>>
>> Anyone use these, they are the BRIGHTEST filaments I've seen, look like
>> Svetlana Triodes.
>>
>> The tubes GE VT25 and RCA VT25...even at 5.0 V AC they are wonderful.
>>
>> The plates run about 305VDC and current about 20mA.
>>
>
>I can confirm that 801s (which oughta be similar) sound great at
>that operating point (300V, 20mA and 6.3V on the filaments).
>
>-Steve
=========================================================================
From: SBench@aol.com
Subject: Re: [JN] 10 Tube, VT25 DC Coupled driven by 6sn7
Date: Sat, 10 Feb 2001 20:16:46 EST
Source: Sound Digest Archive v02.n803
In a message dated 01-02-10 06:46:26 EST, EvaGuido@iaehv.nl writes:
> Guys
>
> Arent these tubes supposed to run on 7.5 V ?
>
> lowering heater voltage will decrease life expectancy......
>
> Enjoy your sound (a little longer :-)
>
Hi,
DHT W-Th filaments when run starved can be regenerated to a large
extent. Procedure is in RCA TT3 among other places. Note that the
operating point chosen is very low with respect to the tubes capability
(6 watts and only 20mA). When running close to the tubes rated
capabilities, starving the filament will indeed lead to (temporarily) reduced
life. With oxide coated devices, the tube cannot successfully be
resuscitated so beware of using that technique on oxide devices
(2A3, 300B etc).
Thanks for the cautionary note.
Best Regards,
Steve
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 10 Tube, VT25 DC Coupled driven by 6sn7
Date: Sun, 11 Feb 2001 22:28:19 +0100
Source: Sound Digest Archive v02.n804
Hi all
Steve wrote:
>DHT W-Th filaments when run starved can be regenerated to a large
>extent. Procedure is in RCA TT3 among other places.
I'll give that a look
>Note that the
>operating point chosen is very low with respect to the tubes capability
>(6 watts and only 20mA).
Yes
> When running close to the tubes rated
>capabilities, starving the filament will indeed lead to (temporarily) reduced
>life. With oxide coated devices, the tube cannot successfully be
>resuscitated so beware of using that technique on oxide devices
>(2A3, 300B etc).
Yes, that is true, however regenerating needs extreme care as the tube may
die as well, if not regnerated the right way (but what can you loose....)
>Thanks for the cautionary note.
thanks !
Guido
>Best Regards,
>Steve
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: [JN] Re: 10 turn ww pots
Date: Sat, 13 Feb 1999 08:42:30 -0500
Source: Sound Digest Archive v02.n044
Various people contributed:
>>>> I believe the ten-turns do not sound OK, though I did not listen to
them........Crack one open and you will see very quickly why. They are made
with a VERY long spirial element. Very high inductance<<<
Gents, this is all opinion. Has anyone actually taken a listen?
Allen (VSE)
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] Re: 10 turn ww pots
Date: Sat, 13 Feb 1999 22:03:46 -0500
Source: Sound Digest Archive v02.n044
At 8:42 AM -0500 2/13/99, Allen Wright wrote:
>Various people contributed:
>
>>>>> I believe the ten-turns do not sound OK, though I did not listen to
>them........Crack one open and you will see very quickly why. They are made
>with a VERY long spirial element. Very high inductance<<<
>
>Gents, this is all opinion. Has anyone actually taken a listen?
>
>Allen (VSE)
10 turn pots can be very noisy and unsatisfactory sonically, if used
directly in the input path.
Grover Gardner
groverg@postoffice.att.net
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: [JN] Re: 10 turn ww pots
Date: Sat, 13 Feb 1999 22:36:57 -0700
Source: Sound Digest Archive v02.n044
>From: Grover Gardner <groverg@postoffice.att.net>
>To: Allen Wright <AllenVSE@compuserve.com>, JoeNet <sound@lists.io.com>
>Subject: Re: [JN] Re: 10 turn ww pots
>Date: Sat, Feb 13, 1999, 8:03 PM
>
> At 8:42 AM -0500 2/13/99, Allen Wright wrote:
>>Various people contributed:
>>
>>>>>> I believe the ten-turns do not sound OK, though I did not listen to
>>them........Crack one open and you will see very quickly why. They are made
>>with a VERY long spirial element. Very high inductance<<<
>>
>>Gents, this is all opinion. Has anyone actually taken a listen?
>>
>>Allen (VSE)
>
> 10 turn pots can be very noisy and unsatisfactory sonically, if used
> directly in the input path.
>
> Grover Gardner
> groverg@postoffice.att.net
- --------------------
I was hoping against hope. Steppers are SUCH a PITA!!
Bill - PEARL
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] Re: 10 turn ww pots
Date: Sun, 14 Feb 1999 22:46:41 +0100
Source: Sound Digest Archive v02.n044
At 08:42 13-2-99 -0500, Allen Wright wrote:
>Various people contributed:
>
>>>>> I believe the ten-turns do not sound OK, though I did not listen to
>them........Crack one open and you will see very quickly why. They are made
>with a VERY long spirial element. Very high inductance<<<
>
>Gents, this is all opinion. Has anyone actually taken a listen?
I suppose...
As I wrote, the series inductance might be a burden, but it depends on the
loading impedance
The proof is in the eating of the pudding. I guess at least I have to buy a
pair
Which brand is reccomended ?
Guido
>Allen (VSE)
>
>
=========================================================================
From: Torsten.Loesch@enhar-ha.nthames.nhs.uk
Subject: Re: [JN] Re: 10 turn ww pots
Date: 15 Feb 1999 11:30:35 +0000
Source: Sound Digest Archive v02.n044
Hi there,
> >>>> I believe the ten-turns do not sound OK, though I did not listen to
> them........Crack one open and you will see very quickly why. They are made
> with a VERY long spirial element. Very high inductance<<<
>
> Gents, this is all opinion. Has anyone actually taken a listen?
I did. While still doing solid Stae. I did not like the sound much. Though
due to low capacitances there was not much rolloff....
I still think that the only way is a stepped (ladder) attenuator. Cermet pots
are close but wear out quickly and often have tracking problems....
Later Thorsten
=========================================================================
From: SBench@aol.com
Subject: [JN] 10W SE No R No C Amp
Date: Sun, 24 Dec 2000 00:56:12 EST
Source: Sound Digest Archive v02.n769
Hi All,
Finally had a bit of time to update my web page. I put up an
845 amp providing about 10 watts using only tubes, transformers
and inductors. Driver stage is differential 6DJ8 (push pull class A
driver) driving SE 845.
Interestingly, provides some insight into how power systems
affect the sound quality! During development I was able to
find topologies producing graininess (traced to limited slew
rate at HF, even though frequency response MEASURED
OK) and classic old style "distorted tube" sound (related
to signal frequency ripple).
Direct access via
http://members.aol.com/sbench/norc845.html
or by the front door at
http://members.aol.com/sbench101
Best of seasons greetings to all.
Steve
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] 10Y (VT-25) vs 801A
Date: Thu, 12 Aug 1999 11:38:23 -0400
Source: Sound Digest Archive v02.n240
I have been exploring this myself. I would assume the 801 is built to allow
more grid current. I know the plate and grid structures are different, the
801 having a boxer, deeper plate. I haven't yet been able to compare the
sound of the two.
jsuen wrote:
>
> Hello,
>
> I would like to know if there is any significant difference between 10Y
> and 801A apart from higher voltage and power ratings of the latter.
- --
Grover Gardner
groverg@postoffice.att.net
=========================================================================
From: jsuen <jsuen@netvigator.com>
Subject: [JN] 10Y (VT-25) vs 801A
Date: Thu, 12 Aug 1999 19:25:33 +0800
Source: Sound Digest Archive v02.n240
Hello,
I would like to know if there is any significant difference between 10Y
and 801A apart from higher voltage and power ratings of the latter.
=========================================================================
From: Carter Hendricks <carter@i1.net>
Subject: [JN] 112A/12A
Date: Wed, 28 Mar 2001 22:48:01 -0600
Source: Sound Digest Archive v02.n847
Does anyone have 4 of these new/used
for purchase or trade???
--Carter
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: [JN] RE: 112 pre with battery filaments
Date: Wed, 06 Dec 2000 17:20:57 -0500
Source: Sound Digest Archive v02.n754
hi folks,
where shall i start?
ok
Q1: should you charge while playing audio?
probably not.
as the bear mentioned below, it sorta defeats the purpose of
battery filaments.
now nicads are known for their very low impedance, and some
folks go on to suggest that they make good "ripple-filters".
but they do have significant impedance at higher frequencies.
the go inductive starting above 100Hz to 1kHz.
Q2: should you use ni-cads or lead-acid?
memory effect is almost a joke in the industry, these days.
most battery engineers consider it an "urban-legend".
most capacity loss in nicad packs is done by heavy discharge
to very low states of charge - i.e. running the batteries flat.
in a series pack of 4 or six cells, oftentimes one or more of these cells (weakest) are forced into
reversal (negative voltage).
this causes premature degradation which some folks attribute to "memory-effect".
overcharging has a similar effect...
now for this application, what is the best choice?
5V @ 0.25A means that you need 4 ni-cads in series (~4.8V).
but the voltage profile if fairly flat.
a D-cell is anywhere between 4 to 5 Ah.
so theoretically, you can get 16-20 hours out of them.
self-discharge is quite high for ni-cads though.
you might want to keep them on a trickle-charge once they're
topped up. C/50, or about 100mA is a good rate.
the charger could be as simple as a constant current source
switchable between a *fast* rate and a *trickle* rate,
or just a single *low* rate for overnight (8-10 hour charging).
you could expect that most of the time, you won't discharge to
zero capacity, so a C/20 rate might be a good compromise.
sealed-lead-acid (SLA) is a fine option, too.
they won't give you as many cycles as nicad. but they are a little easier to charge.
you can build a simple float charger for them using a dc power supply and a resistor. they are bulki
er than nicads, but we're talking
tubes, not cell-phones.
3 in series will give you 6V or so.
paralleling cells with either of these battery types (especially nicad) is not recommended.
if you need more capacity, get a bigger cell.
a separate charger circuit is recommended for each battery.
the circuits should be fairly simple, and easy to replicate.
we're not talking about more than 1A, so a simple LM317 current
source should be sufficient.
3. switch network
i'd recommend a spdt (or DPDT if you want to isolate the grounds, too)
for each battery/filament. in one position you connect the battery
to the filaments, in the other position to the charger.
if you are using cathode bias, i suppose you need a DPDT switch.
if you need any detailed help, just let me know...
hth,
bob.d.
> ----------
> From: Bj> ørn Aaholm[SMTP:bjorn@vt52.com]
> Sent: Wednesday, December 06, 2000 3:19 PM
> To: Joe List
> Subject: SV: [JN] Date: Tue, 5 Dec 2000 18:57:09 -0500
>
> Phil Sieg:
> >
> > Joes,
> >
> > I have the kernel of an idea bubbling in my bonnet and have some questions
> > for those who have gone before. I am working on a design for a phono and
> > line preamp that uses CX-112As in each stage. The stages will be
> > IT-coupled
> > (Sakuma-style, see his 12A/12A/12A/12A/50 phono pre/power amp design at
> > Direct Heating for the general concept).
>
> Mighty interesting...
>
>
>
> > The 112As seem a good candidate for battery filament supplies.
>
> Yes, it indeed does, and this is nothing new. It was designed for battery
> operation.
>
>
> > And here
> > lies my question. I want to use rechargeable NiCad battery packs in
> > parallel with switching to recharge as needed (I hope I'm being
> > clear). I've
> > read Jim de Kort's excellent treatment of the subject on his site (and
> > that's a way cool thing you are doing, Jim) but need a little
> > more detail to
> > implement.>
>
> I'm slightly involved in this project and have myself a UX-226 linestage
> with battery operated filaments. Jim and I have had a lot of conversation
> about how to charge this babies. Now, I don't quite see why you would want
> to use NiCads. They have a most annoying memory effect. Unless you want to
> keep your tubes on until the batteries are virtually drained every time you
> will not have a relaxed relationship with these batteries for long. They
> WILL annoy you... Use lead batteries - these may be more expensive, but they
> last much longer and are much easier to use. If batteries in series are
> needed for an application, parallelling them when charging is definately the
> best and easiest option for a good recharge.
>
>
> > I will use the standard power transformer/valve rectifier for the
> > B+. But I
> > would like to design a battery-based supply that recharges while
> > in use. So
> > I'm looking for help and input from those who have implemented
> > these things.
> > The 12A has 5V, 0.25A filaments.
>
> As I said, I have done this with my 26's. No problems so far AT all. I use 2
> ea 2V 8Ah lead cells in parallel per filament (with drop resistors of
> course). I wouldn't want to charge the supply while in use - you loose
> almost all the benefits of the battery approach...
>
> regards,
> Bjørn Aaholm
>
> http://listen.to/aaholm (Read about my UX-226 linestage here if you want to
> know more)
>
>
=========================================================================
From: "Phil Sieg" <psieg@nxs.net>
Subject: Re: [JN] RE: 112 pre with battery filaments
Date: Wed, 6 Dec 2000 18:50:50 -0500
Source: Sound Digest Archive v02.n754
Bjorn, Bob:
many thanks for your detailed replies. Did a little more research today
(and talked at length with a local DIY friend whose an electronics
instructor at the local Tech Institute). Seems lead acid is the way to go.
Here's the current plan (no pun intended). I will use 6V rechargeable
lead-acid batteries, one per tube. The positive leg will be fitted with a
dropping resistor; the negative with a 120VAC DPDT relay that will be
activated when the rectifier filament supply is turned on
After greater perusal of Jim's site (and increasing appreciation for what
he's doing ), I plan to build a charger per channel that put out 18V with
the batteries in series. It will be switchable separately from the main PS.
The batteries I'm looking at are rated for 1.3Ah for 20 Hr, which means at a
draw of 250 mA, they should last a long time. A *long* listening session
for me is 6-7 hours, and that's only reached usually when we have our
monthly DIY get together. So I can't see the need for parallel batteries
and a switching supply.
So feasible/
Phil
- ----- Original Message -----
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
To: "Joe List" <sound@lists.io.com>
Sent: Wednesday, 06 December, 2000 17.20
Subject: [JN] RE: 112 pre with battery filaments
> hi folks,
>
> where shall i start?
>
> ok
>
> Q1: should you charge while playing audio?
>
> probably not.
> as the bear mentioned below, it sorta defeats the purpose of
> battery filaments.
>
> now nicads are known for their very low impedance, and some
> folks go on to suggest that they make good "ripple-filters".
>
> but they do have significant impedance at higher frequencies.
> the go inductive starting above 100Hz to 1kHz.
>
> Q2: should you use ni-cads or lead-acid?
>
> memory effect is almost a joke in the industry, these days.
> most battery engineers consider it an "urban-legend".
>
> most capacity loss in nicad packs is done by heavy discharge
> to very low states of charge - i.e. running the batteries flat.
>
> in a series pack of 4 or six cells, oftentimes one or more of these cells
(weakest) are forced into reversal (negative voltage).
> this causes premature degradation which some folks attribute to
"memory-effect".
>
> overcharging has a similar effect...
>
> now for this application, what is the best choice?
>
> 5V @ 0.25A means that you need 4 ni-cads in series (~4.8V).
> but the voltage profile if fairly flat.
>
> a D-cell is anywhere between 4 to 5 Ah.
> so theoretically, you can get 16-20 hours out of them.
>
> self-discharge is quite high for ni-cads though.
>
> you might want to keep them on a trickle-charge once they're
> topped up. C/50, or about 100mA is a good rate.
>
> the charger could be as simple as a constant current source
> switchable between a *fast* rate and a *trickle* rate,
> or just a single *low* rate for overnight (8-10 hour charging).
>
> you could expect that most of the time, you won't discharge to
> zero capacity, so a C/20 rate might be a good compromise.
>
> sealed-lead-acid (SLA) is a fine option, too.
> they won't give you as many cycles as nicad. but they are a little easier
to charge.
> you can build a simple float charger for them using a dc power supply and
a resistor. they are bulkier than nicads, but we're talking
> tubes, not cell-phones.
> 3 in series will give you 6V or so.
>
> paralleling cells with either of these battery types (especially nicad) is
not recommended.
> if you need more capacity, get a bigger cell.
>
> a separate charger circuit is recommended for each battery.
>
> the circuits should be fairly simple, and easy to replicate.
> we're not talking about more than 1A, so a simple LM317 current
> source should be sufficient.
>
> 3. switch network
>
> i'd recommend a spdt (or DPDT if you want to isolate the grounds, too)
> for each battery/filament. in one position you connect the battery
> to the filaments, in the other position to the charger.
>
> if you are using cathode bias, i suppose you need a DPDT switch.
>
> if you need any detailed help, just let me know...
>
> hth,
>
> bob.d.
>
> > ----------
> > From: Bj> ørn Aaholm[SMTP:bjorn@vt52.com]
> > Sent: Wednesday, December 06, 2000 3:19 PM
> > To: Joe List
> > Subject: SV: [JN] Date: Tue, 5 Dec 2000 18:57:09 -0500
> >
> > Phil Sieg:
> > >
> > > Joes,
> > >
> > > I have the kernel of an idea bubbling in my bonnet and have some
questions
> > > for those who have gone before. I am working on a design for a phono
and
> > > line preamp that uses CX-112As in each stage. The stages will be
> > > IT-coupled
> > > (Sakuma-style, see his 12A/12A/12A/12A/50 phono pre/power amp design
at
> > > Direct Heating for the general concept).
> >
> > Mighty interesting...
> >
> >
> >
> > > The 112As seem a good candidate for battery filament supplies.
> >
> > Yes, it indeed does, and this is nothing new. It was designed for
battery
> > operation.
> >
> >
> > > And here
> > > lies my question. I want to use rechargeable NiCad battery packs in
> > > parallel with switching to recharge as needed (I hope I'm being
> > > clear). I've
> > > read Jim de Kort's excellent treatment of the subject on his site (and
> > > that's a way cool thing you are doing, Jim) but need a little
> > > more detail to
> > > implement.>
> >
> > I'm slightly involved in this project and have myself a UX-226 linestage
> > with battery operated filaments. Jim and I have had a lot of
conversation
> > about how to charge this babies. Now, I don't quite see why you would
want
> > to use NiCads. They have a most annoying memory effect. Unless you want
to
> > keep your tubes on until the batteries are virtually drained every time
you
> > will not have a relaxed relationship with these batteries for long. They
> > WILL annoy you... Use lead batteries - these may be more expensive, but
they
> > last much longer and are much easier to use. If batteries in series are
> > needed for an application, parallelling them when charging is definately
the
> > best and easiest option for a good recharge.
> >
> >
> > > I will use the standard power transformer/valve rectifier for the
> > > B+. But I
> > > would like to design a battery-based supply that recharges while
> > > in use. So
> > > I'm looking for help and input from those who have implemented
> > > these things.
> > > The 12A has 5V, 0.25A filaments.
> >
> > As I said, I have done this with my 26's. No problems so far AT all. I
use 2
> > ea 2V 8Ah lead cells in parallel per filament (with drop resistors of
> > course). I wouldn't want to charge the supply while in use - you loose
> > almost all the benefits of the battery approach...
> >
> > regards,
> > Bjørn Aaholm
> >
> > http://listen.to/aaholm (Read about my UX-226 linestage here if you want
to
> > know more)
> >
> >
>
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] RE: 112 pre with battery filaments
Date: Wed, 06 Dec 2000 19:07:33 -0500
Source: Sound Digest Archive v02.n754
minor correction phil:
the rating of 1.3AH @ 20hours is simply describing how they measured
the capacity (they used a C/20 rate).
they specify the 20-hour rate because it gives them a better #.
if you used a 2 hour rate (C/2) you would wind up with less capacity
(because of voltage performance).
so you have to stick with the 1.3AH number as a starting point.
this means that you will be able to operate for 1.3AH / 0.25A = 5.2 hours, maximum.
in other words, you're using more like a c/5 discharge rate.
so the capacity will be a little less, and you'll get less run-time.
probably no more than 5 hours.
and when they get near flat, they will drop like a rock
(and potentially cause degradation).
if you use a bigger battery, you will get the potential for longer
run-time, and you'll be going easier on the cells during the one
or two hour sessions. this means you will get more cycles out of them.
also, unless you have a compelling reason to charge the packs in series, i'd suggest doing a 6V char
ger per battery.
it's much easier to manage if there are slight differences from
battery to battery. in series, you are forcing the same charge into each battery. if one reaches ful
l charge first, it will be overcharged, while the others catch up. this will shorten cycle life...
a separate charger, with proper charge termination can extend the life of the batteries, significant
ly.
you should be able to get 500 full cycles from a modern battery.
more if you treat them well (no overcharge, overdischarge/reversal).
less if you abuse them.
good luck,
bob.d.
ps: go for the battery B+ supply, too!!!!
> ----------
> From: Phil Sieg[SMTP:psieg@nxs.net]
> Sent: Wednesday, December 06, 2000 6:50 PM
> To: Danielak, Robert M; Joe List
> Subject: Re: [JN] RE: 112 pre with battery filaments
>
> Bjorn, Bob:
>
> many thanks for your detailed replies. Did a little more research today
> (and talked at length with a local DIY friend whose an electronics
> instructor at the local Tech Institute). Seems lead acid is the way to go.
>
> Here's the current plan (no pun intended). I will use 6V rechargeable
> lead-acid batteries, one per tube. The positive leg will be fitted with a
> dropping resistor; the negative with a 120VAC DPDT relay that will be
> activated when the rectifier filament supply is turned on
>
> After greater perusal of Jim's site (and increasing appreciation for what
> he's doing ), I plan to build a charger per channel that put out 18V with
> the batteries in series. It will be switchable separately from the main PS.
> The batteries I'm looking at are rated for 1.3Ah for 20 Hr, which means at a
> draw of 250 mA, they should last a long time. A *long* listening session
> for me is 6-7 hours, and that's only reached usually when we have our
> monthly DIY get together. So I can't see the need for parallel batteries
> and a switching supply.
>
> So feasible/
>
> Phil
>
>
> ----- Original Message -----
> From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
> To: "Joe List" <sound@lists.io.com>
> Sent: Wednesday, 06 December, 2000 17.20
> Subject: [JN] RE: 112 pre with battery filaments
>
>
> > hi folks,
> >
> > where shall i start?
> >
> > ok
> >
> > Q1: should you charge while playing audio?
> >
> > probably not.
> > as the bear mentioned below, it sorta defeats the purpose of
> > battery filaments.
> >
> > now nicads are known for their very low impedance, and some
> > folks go on to suggest that they make good "ripple-filters".
> >
> > but they do have significant impedance at higher frequencies.
> > the go inductive starting above 100Hz to 1kHz.
> >
> > Q2: should you use ni-cads or lead-acid?
> >
> > memory effect is almost a joke in the industry, these days.
> > most battery engineers consider it an "urban-legend".
> >
> > most capacity loss in nicad packs is done by heavy discharge>
> > to very low states of charge - i.e. running the batteries flat.
> >
> > in a series pack of 4 or six cells, oftentimes one or more of these cells
> (weakest) are forced into reversal (negative voltage).
> > this causes premature degradation which some folks attribute to
> "memory-effect".
> >
> > overcharging has a similar effect...
> >
> > now for this application, what is the best choice?
> >
> > 5V @ 0.25A means that you need 4 ni-cads in series (~4.8V).
> > but the voltage profile if fairly flat.
> >
> > a D-cell is anywhere between 4 to 5 Ah.
> > so theoretically, you can get 16-20 hours out of them.
> >
> > self-discharge is quite high for ni-cads though.
> >
> > you might want to keep them on a trickle-charge once they're
> > topped up. C/50, or about 100mA is a good rate.
> >
> > the charger could be as simple as a constant current source
> > switchable between a *fast* rate and a *trickle* rate,
> > or just a single *low* rate for overnight (8-10 hour charging).
> >
> > you could expect that most of the time, you won't discharge to
> > zero capacity, so a C/20 rate might be a good compromise.
> >
> > sealed-lead-acid (SLA) is a fine option, too.
> > they won't give you as many cycles as nicad. but they are a little easier
> to charge.
> > you can build a simple float charger for them using a dc power supply and
> a resistor. they are bulkier than nicads, but we're talking
> > tubes, not cell-phones.
> > 3 in series will give you 6V or so.
> >
> > paralleling cells with either of these battery types (especially nicad) is
> not recommended.
> > if you need more capacity, get a bigger cell.
> >
> > a separate charger circuit is recommended for each battery.
> >
> > the circuits should be fairly simple, and easy to replicate.
> > we're not talking about more than 1A, so a simple LM317 current
> > source should be sufficient.
> >
> > 3. switch network
> >
> > i'd recommend a spdt (or DPDT if you want to isolate the grounds, too)
> > for each battery/filament. in one position you connect the battery
> > to the filaments, in the other position to the charger.
> >
> > if you are using cathode bias, i suppose you need a DPDT switch.
> >
> > if you need any detailed help, just let me know...
> >
> > hth,
> >
> > bob.d.
> >
> > > ----------
> > > From: Bj> ørn Aaholm[SMTP:bjorn@vt52.com]
> > > Sent: Wednesday, December 06, 2000 3:19 PM
> > > To: Joe List
> > > Subject: SV: [JN] Date: Tue, 5 Dec 2000 18:57:09 -0500
> > >
> > > Phil Sieg:
> > > >
> > > > Joes,
> > > >
> > > > I have the kernel of an idea bubbling in my bonnet and have some
> questions
> > > > for those who have gone before. I am working on a design for a phono
> and
> > > > line preamp that uses CX-112As in each stage. The stages will be
> > > > IT-coupled
> > > > (Sakuma-style, see his 12A/12A/12A/12A/50 phono pre/power amp design
> at
> > > > Direct Heating for the general concept).
> > >
> > > Mighty interesting...
> > >
> > >
> > >
> > > > The 112As seem a good candidate for battery filament supplies.
> > >
> > > Yes, it indeed does, and this is nothing new. It was designed for
> battery
> > > operation.
> > >
> > >
> > > > And here
> > > > lies my question. I want to use rechargeable NiCad battery packs in
> > > > parallel with switching to recharge as needed (I hope I'm being
> > > > clear). I've
> > > > read Jim de Kort's excellent treatment of the subject on his site (and
> > > > that's a way cool thing you are doing, Jim) but need a little
> > > > more detail to
> > > > implement.>
> > >
> > > I'm slightly involved in this project and have myself a UX-226 linestage
> > > with battery operated filaments. Jim and I have had a lot of
> conversation
> > > about how to charge this babies. Now, I don't quite see why you would
> want
> > > to use NiCads. They have a most annoying memory effect. Unless you want
> to
> > > keep your tubes on until the batteries are virtually drained every time
> you
> > > will not have a relaxed relationship with these batteries for long. They>
> > > WILL annoy you... Use lead batteries - these may be more expensive, but
> they
> > > last much longer and are much easier to use. If batteries in series are
> > > needed for an application, parallelling them when charging is definately
> the
> > > best and easiest option for a good recharge.
> > >
> > >
> > > > I will use the standard power transformer/valve rectifier for the
> > > > B+. But I
> > > > would like to design a battery-based supply that recharges while
> > > > in use. So
> > > > I'm looking for help and input from those who have implemented
> > > > these things.
> > > > The 12A has 5V, 0.25A filaments.
> > >
> > > As I said, I have done this with my 26's. No problems so far AT all. I
> use 2
> > > ea 2V 8Ah lead cells in parallel per filament (with drop resistors of
> > > course). I wouldn't want to charge the supply while in use - you loose
> > > almost all the benefits of the battery approach...
> > >
> > > regards,
> > > Bjørn Aaholm
> > >
> > > http://listen.to/aaholm (Read about my UX-226 linestage here if you want
> to
> > > know more)
> > >
> > >
> >
>
>
=========================================================================
From: "Phil Sieg" <psieg@nxs.net>
Subject: Re: [JN] RE: 112 pre with battery filaments
Date: Wed, 6 Dec 2000 20:05:26 -0500
Source: Sound Digest Archive v02.n754
Bob,
Thanks for the corrections. Panasonic has a lead-acid battery rated at
6.5Ah for 20 hrs. At 250 mA, I calculate nearly 24 hrs on that one.
WRT the charger, if I can construct a charger for each channel that can feed
6V to each battery in parallel with the ability to provide at least 2A of
current draw, won't that work as well as separate chargers?
As far as battery B+ goes, let me get the SO used to battery filament
supplies ;-). The idea of 25 12V batteries in series for each channel [3
amplifiers per side using 2 x 45 (woofer); 1 x 45 (mid); 1 x 71A (tweet)],
plus the preamp is a hard sell to a spouse who has always given me free
reign in the audio arena.
Phil
----- Original Message -----
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
To: "Joe List" <sound@lists.io.com>
Sent: Wednesday, 06 December, 2000 19.07
Subject: RE: [JN] RE: 112 pre with battery filaments
> minor correction phil:
>
> the rating of 1.3AH @ 20hours is simply describing how they measured
> the capacity (they used a C/20 rate).
>
> they specify the 20-hour rate because it gives them a better #.
>
> if you used a 2 hour rate (C/2) you would wind up with less capacity
> (because of voltage performance).
>
> so you have to stick with the 1.3AH number as a starting point.
>
> this means that you will be able to operate for 1.3AH / 0.25A = 5.2 hours,
maximum.
>
> in other words, you're using more like a c/5 discharge rate.
> so the capacity will be a little less, and you'll get less run-time.
>
> probably no more than 5 hours.
> and when they get near flat, they will drop like a rock
> (and potentially cause degradation).
>
> if you use a bigger battery, you will get the potential for longer
> run-time, and you'll be going easier on the cells during the one
> or two hour sessions. this means you will get more cycles out of them.
>
> also, unless you have a compelling reason to charge the packs in series,
i'd suggest doing a 6V charger per battery.
>
> it's much easier to manage if there are slight differences from
> battery to battery. in series, you are forcing the same charge into each
battery. if one reaches full charge first, it will be overcharged, while the
others catch up. this will shorten cycle life...
>
> a separate charger, with proper charge termination can extend the life of
the batteries, significantly.
>
> you should be able to get 500 full cycles from a modern battery.
> more if you treat them well (no overcharge, overdischarge/reversal).
> less if you abuse them.
>
> good luck,
>
> bob.d.
>
> ps: go for the battery B+ supply, too!!!!
> > ----------
> > From: Phil Sieg[SMTP:psieg@nxs.net]
> > Sent: Wednesday, December 06, 2000 6:50 PM
> > To: Danielak, Robert M; Joe List
> > Subject: Re: [JN] RE: 112 pre with battery filaments
> >
> > Bjorn, Bob:
> >
> > many thanks for your detailed replies. Did a little more research today
> > (and talked at length with a local DIY friend whose an electronics
> > instructor at the local Tech Institute). Seems lead acid is the way to
go.
> >
> > Here's the current plan (no pun intended). I will use 6V rechargeable
> > lead-acid batteries, one per tube. The positive leg will be fitted with
a
> > dropping resistor; the negative with a 120VAC DPDT relay that will be
> > activated when the rectifier filament supply is turned on
> >
> > After greater perusal of Jim's site (and increasing appreciation for
what
> > he's doing ), I plan to build a charger per channel that put out 18V
with
> > the batteries in series. It will be switchable separately from the main
PS.
> > The batteries I'm looking at are rated for 1.3Ah for 20 Hr, which means
at a
> > draw of 250 mA, they should last a long time. A *long* listening
session
> > for me is 6-7 hours, and that's only reached usually when we have our
> > monthly DIY get together. So I can't see the need for parallel
batteries
> > and a switching supply.
> >
> > So feasible/
> >
> > Phil
> >
> >
> > ----- Original Message -----
> > From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
> > To: "Joe List" <sound@lists.io.com>
> > Sent: Wednesday, 06 December, 2000 17.20
> > Subject: [JN] RE: 112 pre with battery filaments
> >
> >
> > > hi folks,
> > >
> > > where shall i start?
> > >
> > > ok
> > >
> > > Q1: should you charge while playing audio?
> > >
> > > probably not.
> > > as the bear mentioned below, it sorta defeats the purpose of
> > > battery filaments.
> > >
> > > now nicads are known for their very low impedance, and some
> > > folks go on to suggest that they make good "ripple-filters".
> > >
> > > but they do have significant impedance at higher frequencies.
> > > the go inductive starting above 100Hz to 1kHz.
> > >
> > > Q2: should you use ni-cads or lead-acid?
> > >
> > > memory effect is almost a joke in the industry, these days.
> > > most battery engineers consider it an "urban-legend".
> > >
> > > most capacity loss in nicad packs is done by heavy discharge>
> > > to very low states of charge - i.e. running the batteries flat.
> > >
> > > in a series pack of 4 or six cells, oftentimes one or more of these
cells
> > (weakest) are forced into reversal (negative voltage).
> > > this causes premature degradation which some folks attribute to
> > "memory-effect".
> > >
> > > overcharging has a similar effect...
> > >
> > > now for this application, what is the best choice?
> > >
> > > 5V @ 0.25A means that you need 4 ni-cads in series (~4.8V).
> > > but the voltage profile if fairly flat.
> > >
> > > a D-cell is anywhere between 4 to 5 Ah.
> > > so theoretically, you can get 16-20 hours out of them.
> > >
> > > self-discharge is quite high for ni-cads though.
> > >
> > > you might want to keep them on a trickle-charge once they're
> > > topped up. C/50, or about 100mA is a good rate.
> > >
> > > the charger could be as simple as a constant current source
> > > switchable between a *fast* rate and a *trickle* rate,
> > > or just a single *low* rate for overnight (8-10 hour charging).
> > >
> > > you could expect that most of the time, you won't discharge to
> > > zero capacity, so a C/20 rate might be a good compromise.
> > >
> > > sealed-lead-acid (SLA) is a fine option, too.
> > > they won't give you as many cycles as nicad. but they are a little
easier
> > to charge.
> > > you can build a simple float charger for them using a dc power supply
and
> > a resistor. they are bulkier than nicads, but we're talking
> > > tubes, not cell-phones.
> > > 3 in series will give you 6V or so.
> > >
> > > paralleling cells with either of these battery types (especially
nicad) is
> > not recommended.
> > > if you need more capacity, get a bigger cell.
> > >
> > > a separate charger circuit is recommended for each battery.
> > >
> > > the circuits should be fairly simple, and easy to replicate.
> > > we're not talking about more than 1A, so a simple LM317 current
> > > source should be sufficient.
> > >
> > > 3. switch network
> > >
> > > i'd recommend a spdt (or DPDT if you want to isolate the grounds, too)
> > > for each battery/filament. in one position you connect the battery
> > > to the filaments, in the other position to the charger.
> > >
> > > if you are using cathode bias, i suppose you need a DPDT switch.
> > >
> > > if you need any detailed help, just let me know...
> > >
> > > hth,
> > >
> > > bob.d.
> > >
> > > > ----------
> > > > From: Bj> ørn Aaholm[SMTP:bjorn@vt52.com]
> > > > Sent: Wednesday, December 06, 2000 3:19 PM
> > > > To: Joe List
> > > > Subject: SV: [JN] Date: Tue, 5 Dec 2000 18:57:09 -0500
> > > >
> > > > Phil Sieg:
> > > > >
> > > > > Joes,
> > > > >
> > > > > I have the kernel of an idea bubbling in my bonnet and have some
> > questions
> > > > > for those who have gone before. I am working on a design for a
phono
> > and
> > > > > line preamp that uses CX-112As in each stage. The stages will be
> > > > > IT-coupled
> > > > > (Sakuma-style, see his 12A/12A/12A/12A/50 phono pre/power amp
design
> > at
> > > > > Direct Heating for the general concept).
> > > >
> > > > Mighty interesting...
> > > >
> > > >
> > > >
> > > > > The 112As seem a good candidate for battery filament supplies.
> > > >
> > > > Yes, it indeed does, and this is nothing new. It was designed for
> > battery
> > > > operation.
> > > >
> > > >
> > > > > And here
> > > > > lies my question. I want to use rechargeable NiCad battery packs
in
> > > > > parallel with switching to recharge as needed (I hope I'm being
> > > > > clear). I've
> > > > > read Jim de Kort's excellent treatment of the subject on his site
(and
> > > > > that's a way cool thing you are doing, Jim) but need a little
> > > > > more detail to
> > > > > implement.>
> > > >
> > > > I'm slightly involved in this project and have myself a UX-226
linestage
> > > > with battery operated filaments. Jim and I have had a lot of
> > conversation
> > > > about how to charge this babies. Now, I don't quite see why you
would
> > want
> > > > to use NiCads. They have a most annoying memory effect. Unless you
want
> > to
> > > > keep your tubes on until the batteries are virtually drained every
time
> > you
> > > > will not have a relaxed relationship with these batteries for long.
They>
> > > > WILL annoy you... Use lead batteries - these may be more expensive,
but
> > they
> > > > last much longer and are much easier to use. If batteries in series
are
> > > > needed for an application, parallelling them when charging is
definately
> > the
> > > > best and easiest option for a good recharge.
> > > >
> > > >
> > > > > I will use the standard power transformer/valve rectifier for the
> > > > > B+. But I
> > > > > would like to design a battery-based supply that recharges while
> > > > > in use. So
> > > > > I'm looking for help and input from those who have implemented
> > > > > these things.
> > > > > The 12A has 5V, 0.25A filaments.
> > > >
> > > > As I said, I have done this with my 26's. No problems so far AT all.
I
> > use 2
> > > > ea 2V 8Ah lead cells in parallel per filament (with drop resistors
of
> > > > course). I wouldn't want to charge the supply while in use - you
loose
> > > > almost all the benefits of the battery approach...
> > > >
> > > > regards,
> > > > Bjørn Aaholm
> > > >
> > > > http://listen.to/aaholm (Read about my UX-226 linestage here if you
want
> > to
> > > > know more)
> > > >
> > > >
> > >
> >
> >
>
=========================================================================
From: Simon Busbridge <S.C.Busbridge@bton.ac.uk>
Subject: Re: [JN] RE: 112 pre with battery filaments
Date: Thu, 7 Dec 2000 07:37:30 +0000 (GMT)
Source: Sound Digest Archive v02.n754
NiMH? Supposed to be as good as NiCad but without the memory effect.
Never used them personally.
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: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] RE: 112 pre with battery filaments
Date: Thu, 07 Dec 2000 10:36:08 -0500
Source: Sound Digest Archive v02.n755
> Bob,
>
> Thanks for the corrections. Panasonic has a lead-acid battery rated at
> 6.5Ah for 20 hrs. At 250 mA, I calculate nearly 24 hrs on that one.
>
yes, this is more like a C/20 rate (actually C/26).
so you don't really need to make adjustments to available capacity
based upon discharge rate.
6.5AH / .25A = 26 hours.
> WRT the charger, if I can construct a charger for each channel that can feed
> 6V to each battery in parallel with the ability to provide at least 2A of
> current draw, won't that work as well as separate chargers?
>
you really don't want to charge cells in parallel.
this is because you can't guarantee that they will share equally.
you can probably build a single DC supply, then use a current source
circuit (like a LM317 + resistor) for each battery.
this is not too bad, really.
> As far as battery B+ goes, let me get the SO used to battery filament
> supplies ;-). The idea of 25 12V batteries in series for each channel [3
> amplifiers per side using 2 x 45 (woofer); 1 x 45 (mid); 1 x 71A (tweet)],
> plus the preamp is a hard sell to a spouse who has always given me free
> reign in the audio arena.
>
i hear ya.
just figured that if you were taking the plunge.... ;)
take care,
bob.d.
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] RE: 112 pre with battery filaments
Date: Thu, 07 Dec 2000 10:45:58 -0500
Source: Sound Digest Archive v02.n755
NiMH are pretty expensive.
besides that, they require a more complicated charger.
their main benefits include a bit higher energy density
(they're smaller), decent cycle-life, and they're more environmentally friendly.
they are very quickly being overtaken in the market by
Lithium Ion (Li Ion).
i did not suggest Li Ion because the voltage is all wrong
(3.7V average), and because they need special charging techniques,
as well.
also, any commercially available Li ion batteries contain
control/safety electronics which would probably defeat the purpose
(at least philosophically) of using batteeries on toobs....
bob.d.
> ----------
> From: Simon Busbridge[SMTP:S.C.Busbridge@bton.ac.uk]
> Sent: Thursday, December 07, 2000 2:37 AM
> To: Danielak, Robert M
> Cc: Joe List
> Subject: Re: [JN] RE: 112 pre with battery filaments
>
> NiMH? Supposed to be as good as NiCad but without the memory effect.
>
> Never used them personally.
>
> 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: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] RE: 112 pre with battery filaments
Date: Thu, 07 Dec 2000 15:16:10 -0500
Source: Sound Digest Archive v02.n755
> ----------
> From: Jim de Kort[SMTP:jim@vt52.com]
> Sent: Thursday, December 07, 2000 2:26 PM
> To: Danielak, Robert M
> Cc: sound@lists.io.com
> Subject: RE: [JN] RE: 112 pre with battery filaments
>
> Hi,
>
> > > Thanks for the corrections. Panasonic has a lead-acid battery rated at
> > > 6.5Ah for 20 hrs. At 250 mA, I calculate nearly 24 hrs on that one.
>
> >yes, this is more like a C/20 rate (actually C/26).
> >so you don't really need to make adjustments to available capacity
> >based upon discharge rate.
> >
> >6.5AH / .25A = 26 hours.
>
jim wrote:
> Yes, but it will not be giving 6V anymore and we do not live in a
> theoretical world. Take about 70% of that for effective playing time.
>
sure.
i look at it the other way around.
he's already mentioned that his max. run time will be less than 8 hours.
so this guarantees rather shallow discharge cycles, which SLA
batteries prefer. meaning he won't have to replace the batteries in
six months.... ;)
actually, these batteries will probably give close to the calculated run-time, given the resistive l
oading.
the voltage performance issue that you are alluding to is more
of a concern in constant-power application (the most common applications - feeding a dc-dc converter
...or a motor).
> >you really don't want to charge cells in parallel.
> >this is because you can't guarantee that they will share equally.
>
> This is even more so in series. I used to charge my 32 batteries (12V) on a
> single lab supply. It takes a while longer to get them all charged, but in
> the end they do all fill up the same. This is not to say this is a good way
> of charging. Batteries suffer this way as a battery with fuller charge will
> pass (full) current to charge another battery that has been drained more.
>
yeah.
we talked about this before...
individual chargers are the way to go.... ;)
> Best thing to do is use a relay (dual pole, dual contacts) to switch to
> it's own little charger. A 317 costs about $1, plus a few resistors and a
> transisitor, in all that should cost about $5 for an entire charger. Add
> $2-3 for the relay (Siemens has very nice gold-clad silver contact relays)
> and you're done. Two of these will not hurt your bank account ;)))
>
amen...
> >you can probably build a single DC supply, then use a current source
> >circuit (like a LM317 + resistor) for each battery.
>
> Voltage source...
>
right you are.
you can simply build a "float-charger".
this would be a DC regulated supply set to about 2.2 to 2.3V per cell
(6.6 to 6.9V for your 6V battery). it think 6.75V is the recommended
float voltage for most manufacturers.
check the temperatures on the first few charges. if the batteries are getting too hot, reduce the vo
ltage a 10th...
would be a good idea to try to implement current limiting of some sort
in each circuit. find out the max. rate for that cell.
it's probably around 2.5A.
> Yes indeed, this is what I do in my chargers. One big
> rectifier and capacitor and then split to 8 charger circuits.
>
> >just figured that if you were taking the plunge.... ;)
>
> There's an address in the UK (www.steatite.co.uk) that has really cheap
> 12V/2Ah batteries ($6-8 each). If you live in the UK this might be a good
> oppertunity. I would have done it already, but shipping (even to just
> across the channel) is about 4 times that due to weight.
>
>
>
>
> Regards,
>
>
> Jim de Kort
> jim@vt52.com
>
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] RE: 112 pre with battery filaments
Date: Thu, 07 Dec 2000 16:15:22 -0500
Source: Sound Digest Archive v02.n755
> >the voltage performance issue that you are alluding to is more
> >of a concern in constant-power application (the most common applications -
> >feeding a dc-dc converter...or a motor).
>
> A filament would qualify this description.
>
interesting...
i would have considered it purely resistive.
i'll have to think about this....
> >you can simply build a "float-charger".
>
> That is actually what I have. As long as the power switch is turned off,
> the batteries are being charged. The supply is set to 2.3V and current
> limited to C/10 by way of two resistors and a transistor.
>
jim is da' man!
just do as he's done ;)
> >check the temperatures on the first few charges. if the batteries are
> >getting too hot, reduce the voltage a 10th...
>
> My batteries don't even get luke warm. If they are getting warm then the
> current is too high and should be limited. These high currents and
> temperatures limit battery life. The amp has all night to recharge, so no
> hurry, why push 2A into them when 0.5A will do the job in time for the next
> session.
>
there you go...
> >would be a good idea to try to implement current limiting of some sort
> >in each circuit. find out the max. rate for that cell.
>
> Take C/10, it's not the max specification, but it will lengthen tube life
> and still recharge before the morning. See my site for a schematic using
> the current limiter.
>
like i said, jim's da' man!
take care,
bob.d.
=========================================================================
From: "Phil Sieg" <psieg@nxs.net>
Subject: Re: [JN] RE: 112 pre with battery filaments
Date: Thu, 7 Dec 2000 16:31:49 -0500
Source: Sound Digest Archive v02.n755
Jim, Bob,
Thanks again. I think the fog is beginning to clear ;-).
Here's what I've come up with, based on your help.
One Panasonic 6V, 6.5Ah battery for each tube. (Jim, I am in the US.)
A 3-stage version of Tom Ronan's regulator. I have several and can do one
per tube. This gives two stages of voltage reg and one of current reg
(which is decidedly overkill, but my current preamp now has them on the
filament supplies, so my only outlay will be for a few resistors).
I have some Hammond filament trannies (12.6V, 2.5A). Put those in the power
supply chassis - 1 per channel - rectified and filtered , with a NIWW trim
pot to trim the voltage to that required at the inputs of the regulators
(I'll need to drop around 5VDC). Feed the regulators from this DC supply
in parallel
The current reg will be set to allow the battery to draw the 6.75V at 650
MA. Add the relay at the filaments to switch between "charge" and "heat"
plus a separate power switch on the charger supply in the PS chassis.
Sound right? Have I missed anything?
Phil
- ----- Original Message -----
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
To: <sound@lists.io.com>
Sent: Thursday, 07 December, 2000 15.16
Subject: RE: [JN] RE: 112 pre with battery filaments
> > ----------
> > From: Jim de Kort[SMTP:jim@vt52.com]
> > Sent: Thursday, December 07, 2000 2:26 PM
> > To: Danielak, Robert M
> > Cc: sound@lists.io.com
> > Subject: RE: [JN] RE: 112 pre with battery filaments
> >
> > Hi,
> >
> > > > Thanks for the corrections. Panasonic has a lead-acid battery rated
at
> > > > 6.5Ah for 20 hrs. At 250 mA, I calculate nearly 24 hrs on that one.
> >
> > >yes, this is more like a C/20 rate (actually C/26).
> > >so you don't really need to make adjustments to available capacity
> > >based upon discharge rate.
> > >
> > >6.5AH / .25A = 26 hours.
> >
> jim wrote:
>
> > Yes, but it will not be giving 6V anymore and we do not live in a
> > theoretical world. Take about 70% of that for effective playing time.
> >
> sure.
>
> i look at it the other way around.
>
> he's already mentioned that his max. run time will be less than 8 hours.
>
> so this guarantees rather shallow discharge cycles, which SLA
> batteries prefer. meaning he won't have to replace the batteries in
> six months.... ;)
>
> actually, these batteries will probably give close to the calculated
run-time, given the resistive loading.
>
> the voltage performance issue that you are alluding to is more
> of a concern in constant-power application (the most common applications -
feeding a dc-dc converter...or a motor).
>
> > >you really don't want to charge cells in parallel.
> > >this is because you can't guarantee that they will share equally.
> >
> > This is even more so in series. I used to charge my 32 batteries (12V)
on a
> > single lab supply. It takes a while longer to get them all charged, but
in
> > the end they do all fill up the same. This is not to say this is a good
way
> > of charging. Batteries suffer this way as a battery with fuller charge
will
> > pass (full) current to charge another battery that has been drained
more.
> >
> yeah.
> we talked about this before...
>
> individual chargers are the way to go.... ;)
>
> > Best thing to do is use a relay (dual pole, dual contacts) to switch to
> > it's own little charger. A 317 costs about $1, plus a few resistors and
a
> > transisitor, in all that should cost about $5 for an entire charger. Add
> > $2-3 for the relay (Siemens has very nice gold-clad silver contact
relays)
> > and you're done. Two of these will not hurt your bank account ;)))
> >
> amen...
>
> > >you can probably build a single DC supply, then use a current source
> > >circuit (like a LM317 + resistor) for each battery.
> >
> > Voltage source...
> >
> right you are.
>
> you can simply build a "float-charger".
> this would be a DC regulated supply set to about 2.2 to 2.3V per cell
> (6.6 to 6.9V for your 6V battery). it think 6.75V is the recommended
> float voltage for most manufacturers.
>
> check the temperatures on the first few charges. if the batteries are
getting too hot, reduce the voltage a 10th...
>
> would be a good idea to try to implement current limiting of some sort
> in each circuit. find out the max. rate for that cell.
>
> it's probably around 2.5A.
>
> > Yes indeed, this is what I do in my chargers. One big
> > rectifier and capacitor and then split to 8 charger circuits.
> >
> > >just figured that if you were taking the plunge.... ;)
> >
> > There's an address in the UK (www.steatite.co.uk) that has really cheap
> > 12V/2Ah batteries ($6-8 each). If you live in the UK this might be a
good
> > oppertunity. I would have done it already, but shipping (even to just
> > across the channel) is about 4 times that due to weight.
> >
> >
> >
> >
> > Regards,
> >
> >
> > Jim de Kort
> > jim@vt52.com
> >
>
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] RE: 112 pre with battery filaments
Date: Thu, 07 Dec 2000 17:40:32 -0500
Source: Sound Digest Archive v02.n755
depends upon the manufacturer of the cells/packs.
the ubiquitous 18650 cells themselves (made by sony, sanyo, etc)
have built-in PTC devices and pressure switches to protect them from overcharge and over discharge.
some battery packs have external protection and cell-level charge-management circuits.
> ----------
> From: Aigner Josef, Dr.[SMTP:j.aigner@igk.co.at]
> Sent: Thursday, December 07, 2000 5:11 PM
> To: Danielak, Robert M; Joenet (E-Mail)
> Subject: AW: [JN] RE: 112 pre with battery filaments
>
> What kind of safety device ?
>
> Josef
>
> > -----Urspr> üngliche Nachricht-----
> > Von: Danielak, Robert M [SMTP:robert.m.danielak@lmco.com]
> > Gesendet am: Donnerstag, 07. Dezember 2000 16:46
> > An: Joe List
> > Betreff: RE: [JN] RE: 112 pre with battery filaments
> >
> > NiMH are pretty expensive.
> > besides that, they require a more complicated charger.
> >
> > their main benefits include a bit higher energy density
> > (they're smaller), decent cycle-life, and they're more environmentally
> > friendly.
> >
> > they are very quickly being overtaken in the market by
> > Lithium Ion (Li Ion).
> >
> > i did not suggest Li Ion because the voltage is all wrong
> > (3.7V average), and because they need special charging techniques,
> > as well.
> >
> > also, any commercially available Li ion batteries contain
> > control/safety electronics which would probably defeat the purpose
> > (at least philosophically) of using batteeries on toobs....
> >
> > bob.d.
> > > ----------
> > > From: Simon Busbridge[SMTP:S.C.Busbridge@bton.ac.uk]
> > > Sent: Thursday, December 07, 2000 2:37 AM
> > > To: Danielak, Robert M
> > > Cc: Joe List
> > > Subject: Re: [JN] RE: 112 pre with battery filaments
> > >
> > > NiMH? Supposed to be as good as NiCad but without the memory effect.
> > >
> > > Never used them personally.
> > >
> > > 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: StepHydro@aol.com
Subject: [JN] 1200VDC plate on an OPT
Date: Wed, 17 Mar 1999 14:13:47 EST
Source: Sound Digest Archive v02.n078
JN denizens,
I have a friend who is building a pair of PP 845 monoblocs. He wants to run
1200VDC on the plates. His transformers are 80 Watt Peerless.
Does anyone know if Peerless used insualtion on the OPTs that would withstand
that voltage?
Cheers/Carron
=========================================================================
From: Allen Wright <AllenVSE@CompuServe.COM>
Subject: [JN] 120dB ESLs
Date: Thu, 29 Mar 2001 04:42:02 -0500
Source: Sound Digest Archive v02.n847
dnb said "Please tell us more!"
The brand is "monitor DB" and they will be shown at this years Amsterdam AES
by Beyerdynamic (the headphone people) as a potential theater speaker!
It's approx 170 cm high by 50cm wide, a single curved panel like a Martin
Logan. It is not vertically segmented. Looks good but not slick like a ML.
The associated subwoofer is a matching box of the same frontal size, but
perhaps 70cm deep, using 4 ~10" cone woofers in a sealed box.
It is bi-amped, electronically crossing at 115Hz.
The designer is a small commercial speaker manufacturer - doing a range of box
speakers that he sells only in Germany through a dealer network. He does no
advertising, doean't exhibit at trade shows - seems not to need to. No
website!
What I heard was no lashed up prototype - but a full for sale product.
Price - DM35,000 (approx $US15,000) and comparing them to anything else hi-end
hifi they are way underpriced.
I asked what happens when they are overdriven - what's the failure mode?
He said "Don't know - it's never happened. At some technical university they
put in 1200 watts and the measured distortion was lower for the speaker than
the amp..."
Allen (VSE)
=========================================================================
From: "J. Gordon Rankin" <waudio@cinti.net>
Subject: Re: [JN] 120dB ESLs
Date: Thu, 29 Mar 01 07:55:16 -0500
Source: Sound Digest Archive v02.n847
Allen,
So is this 120dB per watt or capable of 120dB?
Do they have a website?
Gordon
=====> Wavelength Audio, ltd. <=====
mailto:waudio@cinti.net
mailto:wavelength@fuse.net
http://www.WavelengthAudio.com
ph.fx. 513-271-4186 USA
=========================================================================
From: David Barnett <d_n_b@swbell.net>
Subject: Re: [JN] 120dB ESLs
Date: Thu, 29 Mar 2001 11:03:42 -0600
Source: Sound Digest Archive v02.n848
On Thu, 29 Mar 2001 07:55:16 -0500, "J. Gordon Rankin"
<waudio@cinti.net> wrote:
>So is this 120dB per watt or capable of 120dB?
I believe it was previously stated that the sensitivity is
~92dB/1W/1M.
- --dnb
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 120dB ESLs
Date: Thu, 29 Mar 2001 20:47:45 +0200
Source: Sound Digest Archive v02.n848
Hi
The perception "per watt" is not correct
It suggests that you get twice the amount of dBs when increasing the power
each watt....
Guido
At 11:03 29-3-01 -0600, David Barnett wrote:
>On Thu, 29 Mar 2001 07:55:16 -0500, "J. Gordon Rankin"
><waudio@cinti.net> wrote:
>
>>So is this 120dB per watt or capable of 120dB?
>
>I believe it was previously stated that the sensitivity is
>~92dB/1W/1M.
>
>--dnb
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] 127 & 50
Date: Sun, 9 Jan 2000 19:50:08 EST
Source: Sound Digest Archive v02.n393
In a message dated 1/9/00 4:58:43 PM US Mountain Standard Time,
mikubala@swissonline.ch writes:
> Is it normal that black gents of Texas speak Russian and have shiny black
shoes???
Texas and normal.
We went to Texas to visit our son and his wife for Thanksgiving.
Driving home, there was an accident on the freeway many miles ahead. All the
pickups and big American sedans, us included, immediately went across the
divider to the frontage road and kept going fast. The minivans and SUVs
stayed in line to wait (city people). It looked like a fancy military parade
maneuver :)
There are lots of people in Texas who listen to music on homebrew amps and
speakers :)
Happy Ears!
Al B^}
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] 127 & 50
Date: Sun, 9 Jan 2000 20:29:25 -0500
Source: Sound Digest Archive v02.n393
- --============_-1264653574==_ma============
Content-Type: text/plain; charset="us-ascii" ; format="flowed"
At 1:07 AM +0100 1/10/01, Miroslav Kubala wrote:
>Hallo
>
>Saturday afternoon I was lucky to get
>1 globe Philco 50 triode , looking brand new and a smaller
>similar looking with blue!! glas " Arturus" brandet 127 tube.....
>I have one more 50 in my collection but - helas ! - not the
>same shape.
>What coud I build with this tubes ???
>Is an other 127 hard to find ( as driver for the 50) ???
>A nice mono amp????
The 50 is limited to 10K grid impedance. You need to use either very
low-impedance driver suitable to drive 10K load, or preferably either
a direct-coupled circuit or interstage transformer for the 50. A
single, plate-loaded 27 won't be much good, I think.
27s are fairly plentiful here, but the older, globe and mesh-plate
types are generally well-used and finding a quiet, well-matched pair
is difficult. Neat tube, though.
- -------
Grover Gardner
groverg@postoffice.att.net
- --============_-1264653574==_ma============
Content-Type: text/enriched; charset="us-ascii"
At 1:07 AM +0100 1/10/01, Miroslav Kubala wrote:
<excerpt><fontfamily><param>Arial</param>Hallo
Saturday afternoon I was lucky to get
1 globe Philco 50 triode , looking brand new and a smaller
similar looking with blue!! glas " Arturus" brandet 127 tube.....
I have one more 50 in my collection but - helas ! - not the
same shape.
What coud I build with this tubes ???
Is an other 127 hard to find ( as driver for the 50) ???
A nice mono amp????
</fontfamily></excerpt><fontfamily><param>Arial</param>
</fontfamily>The 50 is limited to 10K grid impedance. You need to use
either very low-impedance driver suitable to drive 10K load, or
preferably either a direct-coupled circuit or interstage transformer
for the 50. A single, plate-loaded 27 won't be much good, I think.
27s are fairly plentiful here, but the older, globe and mesh-plate
types are generally well-used and finding a quiet, well-matched pair is
difficult. Neat tube, though.
- -------
Grover Gardner
groverg@postoffice.att.net
- --============_-1264653574==_ma============--
=========================================================================
From: "Miroslav Kubala" <mikubala@swissonline.ch>
Subject: [JN] 127 & 50
Date: Wed, 10 Jan 2001 01:07:25 +0100
Source: Sound Digest Archive v02.n393
This is a multi-part message in MIME format.
- ------=_NextPart_000_003A_01C07AA1.B1C9F560
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Hallo
Saturday afternoon I was lucky to get
1 globe Philco 50 triode , looking brand new and a smaller
similar looking with blue!! glas " Arturus" brandet 127 tube.....
I have one more 50 in my collection but - helas ! - not the
same shape.
What coud I build with this tubes ???
Is an other 127 hard to find ( as driver for the 50) ???
A nice mono amp????
Also the new drivers from Supravox are here , named 2000,send in a
wooden box with a HAWWWY alnico magnet,phase plug and a new
suspension I have never seen bevore.
They sound already wunderfull on a open baffle !!!
They also fit in a big horn I got from Holland - there used to be a
Lowther driver .................R.I.P.!!!!
Shall I put pics of the Supravox on my webpage???
By the way , I was saturday in Zurich to get a lesson in
medical astrology!!!??? and 11.15 PM at the bar of the hotel
Baur au Lac I met a black gentleman from Texas with khakkis
and a wonderfull looking hat ( he said the brand is "DOCs") what he
promissed to send me.
Some time later & drinks more Mr.Ali told me that he is a rocket =
ingenieur
and spend lately some time with Mr.#1 of Russia Putin and is on his way =
home.
The funny thing was that again some time etc.later we both ( HE started =
)
have been singing Katusa in russian in the bar of the city of$$$$$$$.
Is it normal that black gents of Texas speak russian and have shiny =
black shoes???
Mirko
www.jurapharmacy.ch
- ------=_NextPart_000_003A_01C07AA1.B1C9F560
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 5.00.2919.6307" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>Hallo</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Saturday afternoon I was lucky to =
get</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>1 globe Philco 50 triode , looking =
brand new and a=20
smaller</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>similar looking with blue!! glas " =
Arturus" brandet=20
127 tube.....</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I have one more 50 in my collection but =
- - helas ! -=20
not the</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>same shape.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>What coud I build with this tubes =
???</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Is an other 127 hard to find ( as =
driver for the=20
50) ???</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>A nice mono amp????</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Also the new drivers from Supravox are =
here , named=20
2000,send in a</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>wooden box with a HAWWWY alnico =
magnet,phase plug=20
and a new</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>suspension I have never seen =
bevore.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>They sound already wunderfull on a open =
baffle=20
!!!</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>They also fit in a big horn I got from =
Holland -=20
there used to be a</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Lowther driver=20
.................R.I.P.!!!!</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Shall I put pics of the Supravox on my=20
webpage???</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>By the way , I was saturday in Zurich =
to get a=20
lesson in</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>medical astrology!!!??? and 11.15 PM at =
the bar of=20
the hotel</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Baur au Lac I met a black gentleman =
from Texas with=20
khakkis</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>and a wonderfull looking hat ( he said =
the brand is=20
"DOCs") what he</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>promissed to send me.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Some time later & drinks more =
Mr.Ali told me=20
that he is a rocket ingenieur</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>and spend lately some time with Mr.#1 =
of Russia=20
Putin and is on his way home.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The funny thing was that again some =
time etc.later=20
we both ( HE started )</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>have been singing Katusa in russian in =
the bar of=20
the city of$$$$$$$.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Is it normal that black gents of Texas =
speak=20
russian and have shiny black shoes???</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Mirko</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><A=20
href=3D"http://www.jurapharmacy.ch">www.jurapharmacy.ch</A></FONT></DIV>
<DIV> </DIV>
<DIV> </DIV></BODY></HTML>
- ------=_NextPart_000_003A_01C07AA1.B1C9F560--
=========================================================================
From: "Joe" <doodle@teleport.com>
Subject: Re: [JN] 127 & 50 & docs
Date: Sun, 9 Jan 2000 22:16:57 -0800
Source: Sound Digest Archive v02.n393
Well regardless of shoes or hat, the guy sounds like an arms dealer
who sells clothing as a sideline..;-) Maybe a Joe-List member should
always try to accompany Mirko on these late night visits to Zurich
Bars. ;-)
Joe Pledger
- ----- Original Message -----
From: David Barnett <davidbarnett@aristotle.net>
To: <sound@lists.io.com>
Sent: Sunday, January 09, 2000 8:36 PM
Subject: Re: [JN] 127 & 50 & docs
> On Mon, 10 Jan 2000 11:41:44 +1100, David Crittle
> <retrovox@bigpond.com> wrote:
>
> >The shiny black shoes (not the hat) are "docs", short for Doctor Martin.
>
> Doctor Martens. A Dane, if I remember correctly.
>
> --dnb
>
=========================================================================
From: David Barnett <davidbarnett@aristotle.net>
Subject: Re: [JN] 127 & 50 & docs
Date: Sun, 09 Jan 2000 22:36:05 -0600
Source: Sound Digest Archive v02.n393
On Mon, 10 Jan 2000 11:41:44 +1100, David Crittle
<retrovox@bigpond.com> wrote:
>The shiny black shoes (not the hat) are "docs", short for Doctor Martin.
Doctor Martens. A Dane, if I remember correctly.
- --dnb
=========================================================================
From: David Crittle <retrovox@bigpond.com>
Subject: [JN] 127 & 50 & docs
Date: Mon, 10 Jan 2000 11:41:44 +1100
Source: Sound Digest Archive v02.n393
>From: "Miroslav Kubala" <mikubala@swissonline.ch>
>I met a black gentleman >from Texas with khakkis and a wonderfull looking
>hat ( he said the brand is "DOCs") what he promissed to send me. Some
>time later & drinks more Mr.Ali told me that he is a rocket ingenieur and
>spend lately some time with Mr.#1 of Russia Putin and is on his way home.
>The funny thing was that again some time etc.later we both ( HE started )
>have been singing Katusa in russian in the bar of the city of$$$$$$$. Is
>it normal that black gents of Texas speak russian and have shiny black
>shoes??? Mirko www.jurapharmacy.ch
Dear Mirko
The shiny black shoes (not the hat) are "docs", short for Doctor Martin.
=========================================================================
From: Tim_Bailey@medibank.com.au
Subject: [JN] Re: 12au7's vs 5687's sound-digest V2 #491
Date: Mon, 27 Mar 2000 11:48:06 +1000
Source: Sound Digest Archive v02.n497
Jim,
Could I suggest that you also try 6cg7's in that circuit. Noval but a direct
electrical 6SN7 equivalent!
I don't think they draw that much more than a 12au7, certainly not as much as a
5687.
Tim B
****************************************************************
NOTICE - This message is intended only for the use of the
addressee named above and may contain privileged and
confidential information. If you are not the intended recipient
of this message you are hereby notified that you must not
disseminate, copy or take any action based upon it. If you
received this message in error please notify Medibank
Private Ltd immediately. Any views expressed in this
message are those of the individual sender, except where
the sender specifically states them to be the views of
Medibank Private Ltd.
****************************************************************
=========================================================================
From: "Hugh R. Dean" <aksa1@optushome.com.au>
Subject: [JN] 12B4
Date: Wed, 28 Feb 2001 20:31:18 +1100
Source: Sound Digest Archive v02.n820
Folks,
I have been thinking about CFs. Have any of you tried the 12B4? It sports
low mu (6.5) and low rp (1030R) and might be a good candidate. Any
experience?
Does it go best with AC or DC heaters?
Thanks,
Hugh
Hugh R. Dean
Research/Technical Director
www.printedelectronics.com
Melbourne AUSTRALIA
=========================================================================
From: David Barnett <d_n_b@swbell.net>
Subject: Re: Sv: [JN] 12B4
Date: Wed, 28 Feb 2001 13:52:03 -0600
Source: Sound Digest Archive v02.n821
On Wed, 28 Feb 2001 19:06:24 +0100, Kurt Steffensen
<kurt-steffensen@teliamail.dk> wrote:
>I once used it for output tube as well.
Julius Futterman used 12B4s as outputs in some of his early,
direct-coupled OTL amplifiers.
- --dnb
=========================================================================
From: "Kurt Steffensen" <kurt-steffensen@teliamail.dk>
Subject: Sv: [JN] 12B4
Date: Wed, 28 Feb 2001 19:06:24 +0100
Source: Sound Digest Archive v02.n821
Hugh and all.
12B4 is one of my favorite tubes from line signals to driver.
And it makes a magnificent CF.
( Are you guys beginning to explore the merits of this wonderfull little circuit ? ;-)
I use DC heaters , though it is probably not really necassary. Depends upon how much noise you accep
t.
12B4 is a triode that does what it is told. Nothing less , nothing more.
DEAD neutral !
And it is able to reproduce a clean 24 bit dynamic range.....
Don't know how it will behave as an MC amp.. The electrode structure is to dramatic for such small s
ignals , for my taste.
But I do not doubt , that the white noise could be low. I would worry about microphonics , at such l
ow levels , though.
I once used it for output tube as well. Cool :-)
It makes a good circlotron , Remco ;-)
And by the way , it is an excellent regulator triode :-)
But 6AS7 and 6336 is better.
What does that YMMV means ?
- - Kurt
=========================================================================
From: Christian Rintelen <christian@rintelen.ch>
Subject: Re: Sv: [JN] 12B4
Date: Wed, 28 Feb 2001 19:55:55 +0100
Source: Sound Digest Archive v02.n821
Kurt,
> Don't know how it will behave as an MC amp.. The electrode structure is to dramatic for such small
signals , for my taste.
> But I do not doubt , that the white noise could be low. I would worry about microphonics , at such
low levels , though.
Why for heavens sake use a tube with mu 6.5 as an mc headamp?! I strongly guess the Joe asking this
was joking...
> And by the way , it is an excellent regulator triode :-)
> But 6AS7 and 6336 is better.
A 6336 makes a purdy impressive linestage, too.... fairly low Rp... ;-) (Actually, I've heard 6336
linestage. It sounded
surprisingly good!)
> What does that YMMV means ?
Your Mileage May Vary (what a weird way to say that your experience may well be different... typical
ly American, I'd say in
my best Swissgerman... ;-)
©
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: Sv: [JN] 12B4
Date: Wed, 28 Feb 2001 23:41:24 +0100
Source: Sound Digest Archive v02.n821
dear all
A 12b4 OTL can be found at
http://www.infomaniak.ch/~bonavolt/12b4.htm
regards
Guido
=========================================================================
From: "Bart Shepherd \(Home\)" <bart.s@bigpond.net.au>
Subject: RE: Sv: [JN] 12B4
Date: Thu, 1 Mar 2001 06:54:21 +1100
Source: Sound Digest Archive v02.n821
>
Behalf Of Christian Rintelen
Sent: Thursday, 1 March 2001 5:56 AM
Why for heavens sake use a tube with mu 6.5 as an mc headamp?! I strongly
guess the Joe asking this was joking...
>
I think that was me - YES, just joking!
Bart
=========================================================================
From: "Paul Croft" <pcroft@iximd.com>
Subject: RE: Sv: [JN] 12B4
Date: Fri, 2 Mar 2001 06:22:33 -0500
Source: Sound Digest Archive v02.n824
Hi Christian,
Yes, it is weirdly American. Due to the government's truth in advertising
laws here, car manufactures generally qualify their mileage claims with the
phrase "Your mileage may vary", as some of us have a heavier foot on the gas
pedal than others.
On this side of the pond, it has become an easy acronym for internet use.
Disgustin', ain't it? (Hmm, didn't Daffy Duck say that? (g))
Cheers,
Paul
> -----Original Message-----
> From: owner-sound@lists.io.com [mailto:owner-sound@lists.io.com]On
> Behalf Of Christian Rintelen
> Sent: Wednesday, February 28, 2001 1:56 PM
> To: Joelist
> Subject: Re: Sv: [JN] 12B4
>
>
> Kurt,
>
> > Don't know how it will behave as an MC amp.. The electrode
> structure is to dramatic for such small signals , for my taste.
> > But I do not doubt , that the white noise could be low. I would
> worry about microphonics , at such low levels , though.
>
> Why for heavens sake use a tube with mu 6.5 as an mc headamp?! I
> strongly guess the Joe asking this was joking...
>
> > And by the way , it is an excellent regulator triode :-)
> > But 6AS7 and 6336 is better.
>
> A 6336 makes a purdy impressive linestage, too.... fairly low
> Rp... ;-) (Actually, I've heard 6336 linestage. It sounded
> surprisingly good!)
>
> > What does that YMMV means ?
>
> Your Mileage May Vary (what a weird way to say that your
> experience may well be different... typically American, I'd say in
> my best Swissgerman... ;-)
>
> ©
>
=========================================================================
From: Steven S <steven@403forbidden.net>
Subject: [JN] 12B4 project ideas?
Date: Tue, 14 Aug 2001 21:39:38 -0400 (EDT)
Source: Sound Digest Archive v02.n946
I've got a stash of mighty nice cryo'd 12b4's (thanks bill!) that i'm
planning on using 2 for my "long term" project (12b4's + 813's + ??) which
leave me with a few to spare. I've been taken with headphone amps lately
since i'm never sitting long enough on the couch to fire up the big guys.
So.. my current thought is to use a input tranny->12B4->output tranny for
a good single tube amp. Throw in a selector switch, volume pot and some
fiddly bits and a good psu... done.
Anyone tried this with this tube? Any thoughts/comments?
=========================================================================
From: pderl@btinternet.com
Subject: Re: [JN] 12B4 project ideas?
Date: Wed, 15 Aug 2001 10:25:52 +0100 (BST)
Source: Sound Digest Archive v02.n946
Hello.
No comment about the headphones, but I have driven 813s with 12B4s. very acceptable although I now
use 6BX7 which provides a little more gain for similar Ra.
Paul
>
> I've got a stash of mighty nice cryo'd 12b4's (thanks bill!) that i'm
> planning on using 2 for my "long term" project (12b4's 813's ??) which
> leave me with a few to spare. I've been taken with headphone amps lately
> since i'm never sitting long enough on the couch to fire up the big guys.
>
> So.. my current thought is to use a input tranny->12B4->output tranny for
> a good single tube amp. Throw in a selector switch, volume pot and some
> fiddly bits and a good psu... done.
>
> Anyone tried this with this tube? Any thoughts/comments?
>
>
=========================================================================
From: "Daniel J. Marshall" <danmarshall@worldnet.att.net>
Subject: [JN] Re: 12 inch Tannoy Golds
Date: Tue, 30 May 2000 11:20:22 -0700
Source: Sound Digest Archive v02.n560
> I just got a pair of 12" Golds, and a summer project of mine
> will be to build some boxes. I have no technical data for
> the drivers or crossovers, so I don't know where to begin.
> I've heard that many cabinets built by Tannoy were too small
> for the drivers (i.e. give a higher WAF while sacrificing bass).
>
> I'd appreciate any help any of you can offer! Thanks!
>
> Randy
Hi Randy,
Some Golds have paper surrounds and some have Butyl, or foam, I forget,
Butyl I think. They would have different fs and Qts, therefore
different parameters and different enclosure requirements. I have
experience only with the paper surrounds. The paper surround units
have a rather High Qts, something like .416, or .436, I forget which.
Their fs was around 49 Hz. If yours have paper surrpounds and are
nearer the 40 Hz fs spec, they would have a lower Qts, perhaps something
near 0.383 which is considered as the ideal value for maximally-flat,
fourth-order Butterworth alignment. VAS was fairly small,