Sound Practices Mailing List Files - Volume 2
=========================================================================
From: KevinC927@aol.com
Subject: [JN] 500v PS caps - move 'em out
Date: Sun, 8 Aug 1999 14:22:03 EDT
Source: Sound Digest Archive v02.n229
I have 10 new (86 date code) 1600uF 500v Sprague Powerlytic caps for sale.
Never made it into an amp that has since metamorphosed.
$8 ea. w/ clamps plus shipping
Kevin Carter
=========================================================================
From: Ishmael349@aol.com
Subject: Re: [JN] 50-50
Date: Sun, 9 Jan 2000 23:44:53 EST
Source: Sound Digest Archive v02.n393
Those same "small-block" Jaguars -- when the boat-anchor was removed and
replaced by the chevy V8, now had 50-50 weight distribution. Me? I built an
1958 MG with a 265 and a three speed. never got it too cool well . . .
always overheated in traffic. I used a straightened out coathanger for the
throttle. How about a 429/500 caddy block for pick-up trucks?
Herb
=========================================================================
From: David Crittle <retrovox@bigpond.com>
Subject: Re: [JN] 50-50
Date: Mon, 10 Jan 2000 20:42:48 +1100
Source: Sound Digest Archive v02.n394
I run a 305 c.i. Chev small block in a 1976 Holden body
>From: Ishmael349@aol.com
>Date: Sun, 9 Jan 2000 23:44:53 EST
>Subject: Re: [JN] 50-50
>To: aspen@alphalink.com.au, sound@io.com
>MIME-Version: 1.0
>Sender: owner-sound@lists.io.com
>Precedence: bulk
>
>Those same "small-block" Jaguars -- when the boat-anchor was removed and
>replaced by the chevy V8, now had 50-50 weight distribution. Me? I built an
>1958 MG with a 265 and a three speed. never got it too cool well . . .
>always overheated in traffic. I used a straightened out coathanger for the
>throttle. How about a 429/500 caddy block for pick-up trucks?
>Herb
>
____________________________
David Crittle
retrovox@bigpond.com
____________________________
Visit the Retrovox Where?house at http://www.users.bigpond.com/retrovox
____________________________
Some pics at
http://albums.photopoint.com/j/AlbumList?u=149682
=========================================================================
From: rchamber@norwich.edu
Subject: [JN] 50s & 60s Jazz LPs on eBay
Date: Tue, 17 Jul 2001 17:52:37 GMT
Source: Sound Digest Archive v02.n926
Joes-
If you are into 50s and 60s jazz and love vinyl, check the ebay offerings
of <elliottg3byy@yahoo.com (37)>.
Especially good if you're in Maidenhead, Berkshire, UK. Standard
disclaimer.
Robert
=========================================================================
From: Svein-Erik Hamran <Svein-Erik.Hamran@ffi.no>
Subject: 515B specs
Date: Tue, 19 Jan 1999 21:52:42 +0100
Source: Sound Digest Archive v02.n001
Hei Joes,
Does any of you know any of the following parameters for the 515B?
Bl, Vas, Xmax, Le, Sd, Mms or Mmd and Cms if possible.
Regards
Svein-Erik
=========================================================================
From: Paul Mouritsen <mourip@erols.com>
Subject: [JN] 5687 design values...
Date: Sun, 13 Jun 1999 18:03:16 -0400
Source: Sound Digest Archive v02.n176
Hi,
I am doing a bit of experimenting with input tubes for my 71A amp. I am
thinking of using a 5687 as a simple gain stage. My power supply gives me
about 220 volts after the main filtration. Could a 5687 be run directly,
through a plate choke at that voltage or does it really sound best at a
lower voltage and higher current? Also if 220 volts is a "sound" choice for
that tube could some one walk me through calculating the cathode resistor
value. Any suggestions for an optimal voltage and current? Any schematics
you could point me to? Most of the schematics in SP seem to be for SRPP
using that tube...
Thanks a lot,
Paul
Please remove the xxx's in my email address to reply.. Thanks
*****************************************************************************
Paul Mouritsen.....mourip@erols.com
If you want to make God laugh, tell him your plans...
La luce che tu dai
*****************************************************************************
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: [JN] 5687 design values...
Date: Sun, 13 Jun 1999 19:46:17 -0600
Source: Sound Digest Archive v02.n176
Hi Paul:
Measure the DCR of your loading choke in ohms and multiply that value by
the current in amps that want flowing thru your 5687; this will give you the
DC voltage drop across your choke. Subtract this value from the votage value
of your B+; this will give you voltage that will appear on the plate of your
5687.
Pull out your curves of 5687 plate characteristics; this chart will have
plate current plotted on the vertical axis, plate voltage on the horiz. axis
and about a dozen or so curves that start from different places along the
horiz. axis and run upwards and towards the right. Each of these curves
corresponds to a fixed value of control-grid-to-cathode voltage and each is
marked by some value of voltage, usually between +10V and 70V; these are
most positive and most negative values seen on most sets of curves for low
to medium mu tubes
Using these curves, you can fix any two of the three values - plate
current, plate voltage or control-grid voltage - and derive the third.
By now, you have to defined a plate current, derived a plate voltage and
need to determine the value of negative control-grid-to-cathode voltage that
will allow your desired plate current to flow given your plate voltage.
Find the spot on the plate characteristic chart's vertical axis that
corresponds to the plate current you want flowing thru your tube - this is
the same value that you used to calculate the voltage drop across the choke
- - run a line from that spot horizontally across the chart.
Find the spot on the horiz. axis axis that corresponds to the plate
voltage your tube will 'see' - run a line from that spot vertically up the
chart.
The point at which these two lines intersect will, amoung the family of
curves plotted on the chart, correspond to the negative grid-voltage
required to bias the tube 'down' the plate current you desire given the
voltage appearing at the plate.
It's unlikely that you'll 'hit' one of the curved lines spot on so
you'll have to interpolate between the two immediately adjacent curves that
intersect your horizontal line - do your interpolation along your horizontal
line
If you plan to use fixed bias of some sort, this voltage will be the one
you need to apply to the control grid - usually thru some high value
resistor; typically 100K to 1Meg
If you plan to use, cathode bias (capacitor-bypassed or not) then you
need to calculate the value of resistance needed between cathode and ground
- - assuming that your control grid is also tied to ground thru some high
value; typically 100K to 1Meg.
To obtain this value, divide the absolute value of the required (and
likely interpolated) grid-bias voltage by the current - in amps - that is to
flow thru the tube. The resulting value will be in ohms.
To arrive at a wattage rating for this resistor, square the value of the
voltage dropped across this resistor by the resistor's value.
This will get you 'into the ball park'.
Techincally though, you could subtract the voltage that will be dropped
across your cathode resistor from your plate voltage and re-determine the
negative, control-grid-to-cathode voltage. As this value is not likely to be
materially different from the first approximation; tubes vary one to the
next and you likely don't care that the plate current be EXACTLY equal to
some arbitrary, calculated value; the 'first shot' is generally perfectly
adequate.
Note however that in the case where the cathode resistor is left
unbypassed, the effect of the cathode resistor is to 'linearize' the plate
current to plate voltage relationship. This is the result of a benign form
of feedback known as 'cathode degeneration'.
Some folks like the sound of it . . . some don't . . . .
That oughta do ya . . . . have fun ! ! ! !
Bill Perkins, PEARL Inc.
2528 19 St. S.W., Calgary, Ab.,
Canada T2T 4X3
Ph. 1 403 244 4434 Fx. 1 403 244 9026
- ----------
>From: Paul Mouritsen <mourip@erols.com>
>To: sound@lists.io.com
>Subject: [JN] 5687 design values...
>Date: Sun, Jun 13, 1999, 4:03 PM
>
> Hi,
>
> I am doing a bit of experimenting with input tubes for my 71A amp. I am
> thinking of using a 5687 as a simple gain stage. My power supply gives me
> about 220 volts after the main filtration. Could a 5687 be run directly,
> through a plate choke at that voltage or does it really sound best at a
> lower voltage and higher current? Also if 220 volts is a "sound" choice for
> that tube could some one walk me through calculating the cathode resistor
> value. Any suggestions for an optimal voltage and current? Any schematics
> you could point me to? Most of the schematics in SP seem to be for SRPP
> using that tube...
>
>
>
> Thanks a lot,
>
> Paul
>
> Please remove the xxx's in my email address to reply.. Thanks
>
>
>
> *****************************************************************************
> Paul Mouritsen.....mourip@erols.com
>
> If you want to make God laugh, tell him your plans...
>
> La luce che tu dai
>
> *****************************************************************************
>
>
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] 5687 design values...
Date: Sun, 13 Jun 1999 20:30:34 -0400
Source: Sound Digest Archive v02.n176
Personally, I like the 5687 at 200+ plate volts. Try a 680 ohm cathode
resistor and shoot for 10-12 volts bias.
Paul Mouritsen wrote:
>
> Hi,
>
> I am doing a bit of experimenting with input tubes for my 71A amp. I am
> thinking of using a 5687 as a simple gain stage. My power supply gives me
> about 220 volts after the main filtration. Could a 5687 be run directly,
> through a plate choke at that voltage or does it really sound best at a
> lower voltage and higher current? Also if 220 volts is a "sound" choice for
> that tube could some one walk me through calculating the cathode resistor
> value. Any suggestions for an optimal voltage and current? Any schematics
> you could point me to? Most of the schematics in SP seem to be for SRPP
> using that tube...
- --
Grover Gardner
groverg@postoffice.att.net
=========================================================================
From: Scott Grammer <tubedude@cdc.net>
Subject: Re: [JN] 5687 design values...
Date: Sun, 13 Jun 1999 22:49:07 -0400
Source: Sound Digest Archive v02.n176
Paul Mouritsen wrote:
> Hi,
>
> I am doing a bit of experimenting with input tubes for my 71A amp. I am
> thinking of using a 5687 as a simple gain stage. My power supply gives me
> about 220 volts after the main filtration. Could a 5687 be run directly,
> through a plate choke at that voltage or does it really sound best at a
> lower voltage and higher current?(snip)
I think you could, but it would have to be a pretty high value plate choke. I had
a chance to tinker with 5687's about a year and a half ago, and they always
seemed to sound better with a fairly low voltage and a lot of current. I think I
settled on 150V and 20mA.
S.G.
- --
TubeDude's Webpage of Vacuum Tube Lore! http://www.cdc.net/~tubedude/
Smoke Free Youth! http://www.cdc.net/~tubedude/smokefreeyouth.html
The Price of Privacy. http://www.cdc.net/~tubedude/privacy.html
"The nice thing about standards is that you have so many to choose from."
-- Andrew S. Tanenbaum, _Computer Networks_, 2nd ed, p.254
=========================================================================
From: "johari yip" <hfyip@pacific.net.sg>
Subject: Re: [JN] 5687 design values...
Date: Mon, 14 Jun 1999 19:28:51 +0800
Source: Sound Digest Archive v02.n177
- ----- Original Message -----
From: Scott Grammer <tubedude@cdc.net>
To: Paul Mouritsen <mourip@erols.com>; Joenet <sound@lists.io.com>
Sent: Monday, June 14, 1999 10:49 AM
Subject: Re: [JN] 5687 design values...
Scott, you wrote
>
> I think you could, but it would have to be a pretty high value plate
choke. I had
> a chance to tinker with 5687's about a year and a half ago, and they
always
> seemed to sound better with a fairly low voltage and a lot of current. I
think I
> settled on 150V and 20mA.
At this setting, I have the best "dynamics" and "pace" in the presentation.
Lesser current through the tube will yield a "slower" by "thicker" sounding
presentation. I would be curious to know how the 5687 would sound when the
cathode resistor is replaced with a choke, say 30H, with a DCR value same as
the cathode resistor. Has anyone try anything like this or is this something
that would not work. Appreciate the feedback.
Johari
=========================================================================
From: Paul Mouritsen <mourip@erols.com>
Subject: [JN] 5687 Design Values...Thanks
Date: Sun, 13 Jun 1999 22:36:45 -0400
Source: Sound Digest Archive v02.n176
(Hi. I think that my email is bonkers. Please excuse me if this gets posted
twice or if you get multiple copies directly)
Thanks Larry and Grove and Bill for the speedy help. I had found the curves
at the Duncan Amp Page and made an honest attempt to figure it out but the
place I occupy on this learning curve is not too linear yet and is all
uphill. After reading Bill's reply it all made much more sense. From what
you all wrote I can get a good start on trying the 5687.
My amp currently has a 5842 in it. The microphonics are a bit too
troublesome for a headphone amp plus I have to admit that I find this tube
a bit bright and dry. I like detail but I would rather have a more
"romantic" presentation. This quest seems a bit endless. No sooner do I
find a happy place then I start looking for a way to make it better. I
guess I need a listening amp and a play amp. I have several 1626's on the
way so perhaps that will be a place to start...
Thanks again,
Paul
>At 08:31 PM 6/13/99 -0400, you wrote:
>>Paul:
>>
>>At higher voltage and lower current the 5687 sweetens up a bit. As you go
>>lower and hotter it gets a bit more gutsy. So, having said that, the max
>>plate watts is 4.2 per section. So, 4.2=220*i....This means 19mA is the
>>maximum current without exceeding the plate dissipation. The max plate
>>voltage is 300.
>>
>>As to the cathode resistor, from my curves (these are on the web somewhere)
>>at 220 and 19mA looks like about 9.5 volts. So, 9.5/19mA is 500 ohms.
>>
>>Personally, I like the 5687 at 8-10mA. For this at 220 and 10mA, the
>>cathode resistor is, since the curves show aboout 11 volts on the grid, 1k.
>>
>>For the lower 3dB point f=1/(2*pi*R*C), so you'll want for 5Hz, 64uF for
>>500 and 32uF for 1k. Some where in this neighborhood should get you there.
>>
>>The AN Ongaku runs the 5687 where I like it as well for what that is worth.
>> All in all it sounds great at all volatges to me.
>>
>>L.D. Moore
>>
>>At 06:03 PM 6/13/99 -0400, you wrote:
>>>Hi,
>>>
>>>I am doing a bit of experimenting with input tubes for my 71A amp. I am
>>>thinking of using a 5687 as a simple gain stage. My power supply gives me
>>>about 220 volts after the main filtration. Could a 5687 be run directly,
>>>through a plate choke at that voltage or does it really sound best at a
>>>lower voltage and higher current? Also if 220 volts is a "sound" choice for
>>>that tube could some one walk me through calculating the cathode resistor
>>>value. Any suggestions for an optimal voltage and current? Any schematics
>>>you could point me to? Most of the schematics in SP seem to be for SRPP
>>>using that tube...
>>>
>>>
>>>
>>>Thanks a lot,
>>>
>>>Paul
>>>
>>>Please remove the xxx's in my email address to reply.. Thanks
>>>
>>>
>>>
>>>*************************************************************************
****
>>> Paul Mouritsen.....mourip@erols.com
>>>
>>> If you want to make God laugh, tell him your plans...
>>>
>>> La luce che tu dai
>>>
>>>*************************************************************************
****
>>>
>>>
>>>
>>>
>>
>>
Please remove the xxx's in my email address to reply.. Thanks
*****************************************************************************
Paul Mouritsen.....mourip@erols.com
If you want to make God laugh, tell him your plans...
La luce che tu dai
*****************************************************************************
=========================================================================
From: Tim_Bailey@medibank.com.au
Subject: [JN] Re: 5687 info
Date: Fri, 17 Dec 1999 12:53:15 +1100
Source: Sound Digest Archive v02.n367
****************************************************************
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.
****************************************************************
repeat of separate individual post (edited)
Good to know a 5687 isn't taller than a 12AX7. Can't use 6cg7's for line duties
because they're too tall.
What are a 5687's strengths in phono use.
In line out use eg output impedance and drive capability in anode follower mode,
one triode only, I presume they are a twin triode?
I bet the pinout's are like a 6CG7 or 6DJ8.
What advantages would there be in using them for a tape in/out buffer, or would
6072/12 AY7's be better?
How good are Cv 4004's (advantages) Hugh are they quieter or do they have more
gain.
Regards
Tim B
=========================================================================
From: "Hugh R. Dean" <aspen@alphalink.com.au>
Subject: Re: [JN] Re: 5687 info
Date: Fri, 17 Dec 1999 19:48:44 +1100
Source: Sound Digest Archive v02.n367
Hi Tim,
> What are a 5687's strengths in phono use.
High plate current is an old RF trick to reduce the noise generated by
largish plate resistors. It works. A 5687 at 18mA is very quiet; a
typical plate resistor is less than 10K. Similar approaches are used for
the 6DJ8, 417A, 6922 and 6GK5 - all high current, low noise frame grids I
believe.
> In line out use eg output impedance and drive capability in anode follower
mode,
> one triode only, I presume they are a twin triode?
Yes, they are twins. rp is only 2000R; very low. Furthermore, grid bias
is fairly high, typically 8-12V minus, so these tubes have an enormous
overload margin at the grid. This makes them very suitable as drivers.
> I bet the pinout's are like a 6CG7 or 6DJ8.
Not sure. Not in my book. Check Jim de Kort's site at http://www.vt52.com/
Much more drive, so far less sensitive to interconnects and loading.
But mu is only about 17, compared to mu 40 for the 12AY7 and I think - don't
quote me - around 50 for the 6072.
> How good are Cv 4004's (advantages) Hugh are they quieter or do they have
more
> gain.
CV4004s are the British milspec on 12AX7s. They have identical gain,
transconductance etc but are definitely quieter. I believe they actually
sound better than Mullard 12AX7s, too.
Cheers,
Hugh
=========================================================================
From: Tim_Bailey@medibank.com.au
Subject: [JN] Re: Re(2): 5687 info -preamps and phono.
Date: Tue, 25 Jan 2000 16:41:07 +1100
Source: Sound Digest Archive v02.n416
****************************************************************
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.
****************************************************************
Fred, Allen W., et al
- ---------------------- Forwarded by Tim Bailey/BusSys/MPL on 25/01/2000 04:31 PM
- ---------------------------
Tim Bailey
25/01/2000 10:53 AM
To: Torsten.Loesch@enhar-ha.nthames.nhs.uk @ MPLPUBLIC
cc:
Subject: Re: Re(2): 5687 info -preamps and phono. (Document link: Tim Bailey)
Further query re above. sorry for the long post
Why is anode follower better than CF for a triode? what is the effect
especialyy with a 5687 if used in parallel to lower output impedance? (my set
up uses long interconnects to the power amps ie about 7 metres and short spkr
cables).
I understand that poor pair matching in twin triodes and across tubes is an
issue for many of you, eg concerning PSE for power amps. One reason I have for
asking is I'm thinking about the very positive critical reaction to the multi
paralleled zero feedback triode line stage preamps by CJ? I amthinking about
paralleling one or two 6cg7's in my envisioned next all-singing pre-amp.
Could AF also be applied to my 12au7?13d5 line stage? This currently has Brimar
13d5'd in it, I also have a pr of philips EC 6189wa's.
I was interested in the Height of the 5687 because if I were to use it in my
preamp to replace the 12au7's it would need to fit.
As my current preamp is a gutted Quad 22 box, tube height is a constraint, which
is why I didn't use 6cg7's in the line stages last upgrade.
I did not DIY this though. I have a problem with how it was done in that I have
to remember to switch the Stereo button and the source button in' to send a tape
signal out. I must also remember never to attempt to listen to the tape replay
from the third head at the same time (massive howl round results if both the
stereo (tape out) and tape button are pressed in). I think it is to do with the
switching array, there are a stereo button, a mono button (not put into use
itc), and then Radio, Mic, Disc, and Tape buttons. Is there some unavoidable
reason why this howl-round must happen? ie is there some other way just using 4
twin triodes (2 for phono use). I may have to put in a ss chio tape buffer on a
little board with a view to saleability, when my conceptual 'last preamp' is
finished
I am nutting out some requirements cf options for my next preamp. I have a nice
big well shielded box to put it in, from one of Allen Wright's SS AM tuners. Hey
Allen, sorry mate but it just died in several ways, and I had to give Tim
Casimir's one back.
[So now Ihave a restored/modded Kenwood/Trio W8 tubed stereo receiver with; for
FM a SS decoder (Studio 12), AM is simply glorious with all the extra tube
sockets from AM section 2 in use. A very long 'random' wire antenna and a
tapped inductor and a variable cap also help. BTW, using a 300ohm ribbon for
the last section into the house really does help with noise! so do good earth
stakes!]
While I was grateful for everbody's generosity with their knowledge, I am now
not going to pursue the LDR remote volume control idea, due to lack of spare
time. Nor will I pursue the 6j6 7pin twin triode for phono. I may use these as
buffer tubes for EPL/tape loops and listen / record buffering, applying AF or CF
mode. Any non-linearities in this abundant and cheap tube (as identified by
Fred Voltz), would probably be eliminated/or less significant in these roles.
I am still interested in a remote volume control, possibly of limited 9-12db
range, with overall gain set suitably by a fixed resistor for each source. I
also want remote mute and absolute polarity switching. Could I use a (stepper?)
motor to switch a small array of precision resistors? The polarity switching
would be at the line driver stage output, after the "pot". This is also where
the muting would be.
I know that many people will consider all this as 'laziness' and these 'issues'
as an inevitable and necessary cost of circuit simplicity and clarity. My
reason for wanting these facilities on remote is not to avoid, but muting to
respond to telephones and the front door, and 'focussing' the sound both in
level and phase at my seat. The distance between my system centre and the
'seat' means that I have to walk from the system through the dining room and
back to my seat after selecting either a tape or vinyl source, or loading a CD.
A stuffed lowering device on my 'dear old SME' adds to this, as I have to lower
by hand, still with the lever, and then miss the opening bars in stereo as I
walk briskly back. I will not be giving up this walk to cue up, but would
prefer to be able to press 'start' at my seat.
I would be very interested if there was ever a project for a remotely
triggerable arm lowerer and lifter. One problem being how to trigger it without
causing RFI (crackle and thumps) through all that phono stage gain.
I would also be interested in knowing if the remote wired facility on
Nakamichi's cassette decks, ever received an IR retrofit or DIY solution?
Who dares to say this man is a perfectionist?!
Regards to all
Tim B
=========================================================================
From: Andrew Brandon <ajbrandon@yahoo.com>
Subject: [JN] 5687 line amp
Date: Mon, 17 Apr 2000 11:50:34 -0700 (PDT)
Source: Sound Digest Archive v02.n523
Hello all,
Has anyone tried / heard the line amp on the Pats
Schematics Page. He refers to it as Pat's Ultimate
preamp. It uses a 5687.
It looks simple enough.
http://nanaimo.ark.com/~pat/mu.jpg
TIA
Andrew
__________________________________________________
Do You Yahoo!?
Send online invitations with Yahoo! Invites.
http://invites.yahoo.com
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 5687 line amp
Date: Mon, 17 Apr 2000 23:25:14 +0200
Source: Sound Digest Archive v02.n524
Andrew
Personally I do not like SRPP
Start with standard grounded cathode amp and you may expand to SRPP later
(and eventually return to ......)
The output cap is way to big for tube amps, the cathode cap too small.....
PSRR of 45 dB would be nice but is impossible from my first hand calculation
Succes
Guido
At 11:50 17/04/2000 -0700, Andrew Brandon wrote:
>Hello all,
>
>Has anyone tried / heard the line amp on the Pats
>Schematics Page. He refers to it as Pat's Ultimate
>preamp. It uses a 5687.
>
>It looks simple enough.
>
>http://nanaimo.ark.com/~pat/mu.jpg
>
>TIA
>
>
>Andrew
>
>
>
>__________________________________________________
>Do You Yahoo!?
>Send online invitations with Yahoo! Invites.
>http://invites.yahoo.com
>
>
=========================================================================
From: Kurt Steffensen <kurt-steffensen@teliamail.dk>
Subject: Re: [JN] 5687 line amp
Date: Tue, 18 Apr 2000 00:58:25 +0300
Source: Sound Digest Archive v02.n524
evaguido wrote:
> Andrew
>
> Personally I do not like SRPP
>
> Start with standard grounded cathode amp and you may expand to SRPP later
> (and eventually return to ......)
>
> The output cap is way to big for tube amps, the cathode cap too small.....
>
> PSRR of 45 dB would be nice but is impossible from my first hand calculation
Hi Andrew.
I agree with , Guido , in all three here....
The output cap is way to big. ( Unless he is into 8 Ohm loudspeakers directly
;-)
Even one of the 5 uF's , will be plenty for most loads....
And the cathode bypass is much to small , either remove it entirely , or replace
it with say 100-220 uF.
The input impedance is 1 M Ohm , not that 338 kOhm , that is refered.
And , I haven't checket with the maths , but I do not belive the 100 Ohm Z-out
either.
SRPP's in my opinion is good in RIAA stages.
But at line levels and beyond that , I agree with Guido , no reason to use
SRPP..
5687 is a good tube , though , and a simple resistor on the plate , will do
wonders :-)
Well , that's just Guido's and my oponions , right ? :-)
But it is very easy to check them out , yourself , in your system , and in to
your ears..
Simply start with the amp , just as it is suggested in the scematic , then
replace the 50 uF mesh , with a simple say 1 u , then remove the 6u ( ? :-) )
from the cathode resistor , finally replace the upper triode , with a resistor (
Or IT / choke ).
Maybe you do not agree , with us ?
Or maybe you do....? ;-).
But at least , you would have the fun , and you would have the experience ,at
first hand..( Ear , that is )
- ------- Kurt
=========================================================================
From: Andrew Brandon <ajbrandon@yahoo.com>
Subject: [JN] 5687 line amp
Date: Tue, 18 Apr 2000 14:55:53 -0700 (PDT)
Source: Sound Digest Archive v02.n525
I found this version of the same line amp on the site
below. Same designer. The paralleled caps on the upper
tubes cathode are a single 5uF and the 6uF is removed
from the lower tube, there also appears to be a
resistor change on the lower tubes cathode to 500R (I
don't have the schematic that I wrote of first with
me,I'm going from memory).
From the respones I have seen it seems that this
version is more like what would be expected.
Thanks to all who have responded, I am going to build
the circuit in all its configurations including a rc
and transformer coupled version. ( yup, I get to have
all the fun !)
Thanks again
Andrew
BTW, I plugged my "old" pentode cf line amp back into
the system about a week ago and thought it sounded
pretty good but a bit bright so i changed the Sovtek
6922 for a Svet 6n1p that I had ordered for the
purpose but never got around to (been using a 6j5
transformer coupled ultrapath) and that tube changed
the sound totally. Smoothed that brightness and seems
to be more detailed at the same time. Better bass than
the ultrapath but not as natural sounding.
http://www.infomaniak.ch/~bonavolt/5687line.htm
__________________________________________________
Do You Yahoo!?
Send online invitations with Yahoo! Invites.
http://invites.yahoo.com
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 5687 line amp
Date: Tue, 18 Apr 2000 20:50:13 +0200
Source: Sound Digest Archive v02.n525
Hey Krut,
As long as we don't discuss cathode followers and power supply regulators
we seem to agree :-)
See you in August !
regards,
- -
Guido
>> Personally I do not like SRPP
>>
>> Start with standard grounded cathode amp and you may expand to SRPP later
>> (and eventually return to ......)
>>
>> The output cap is way to big for tube amps, the cathode cap too small.....
>>
>> PSRR of 45 dB would be nice but is impossible from my first hand
calculation
>
>Hi Andrew.
>
>I agree with , Guido , in all three here....
>The output cap is way to big. ( Unless he is into 8 Ohm loudspeakers
directly
>;-)
>Even one of the 5 uF's , will be plenty for most loads....
>
>And the cathode bypass is much to small , either remove it entirely , or
replace
>it with say 100-220 uF.
>
>The input impedance is 1 M Ohm , not that 338 kOhm , that is refered.
>And , I haven't checket with the maths , but I do not belive the 100 Ohm
Z-out
>either.
>
>SRPP's in my opinion is good in RIAA stages.
>But at line levels and beyond that , I agree with Guido , no reason to use
>SRPP..
>5687 is a good tube , though , and a simple resistor on the plate , will do
>wonders :-)
>
>Well , that's just Guido's and my oponions , right ? :-)
>
>But it is very easy to check them out , yourself , in your system , and in to
>your ears..
>
>Simply start with the amp , just as it is suggested in the scematic , then
>replace the 50 uF mesh , with a simple say 1 u , then remove the 6u ( ? :-) )
>from the cathode resistor , finally replace the upper triode , with a
resistor (
>Or IT / choke ).
>
>Maybe you do not agree , with us ?
>Or maybe you do....? ;-).
>But at least , you would have the fun , and you would have the experience ,at
>first hand..( Ear , that is )
>
>------- Kurt
>
>
>
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 5687 line amp
Date: Tue, 18 Apr 2000 20:55:27 +0200
Source: Sound Digest Archive v02.n525
dear Pat,
you wrote:
>as the "designer" of this, let me say i read the PS RR from TUBE CAD.
>as for the size of the OUTPUT CAPS, if you use parallel small caps you dont
>lose any pulse rise time,
Because of reduced self inductance ?
>and they are LARGE TO GIVE FLAT 20cps frequency
>response into 150ohm load...for two sets of Sennheiser headphones.
In that load you need big caps but I have very serious doubts if this
circuit "likes" these loads
>also, grounded CATHODE is stupid, in my opinion.
Oh ?
What is in the original cicrcuit (SRPP) looks like grounded cathode, no ?
>the cathode resistor acts as a fuSE in the case of a heater cathode short.
That depends on the voltage in-between heater and ground, and the driving
impedance of that source. And then again, what is the difference with your
circuit ?
>( in the REAL world)
>i dont care about ABSOLUTE MU figures..who cares if you are getting EVERY
>POSSIBLE drop of GAIN.
I try to adapt my cicruits with respect to gain, in order to bennefit from
other advantages that I get once gain is reduced to the gain I need.
Have fun
Guido
>ø¤ º°`°º¤ø,¸¸¸,ø¤º°`°º¤ø,¸¸¸,ø¤º°
>
> ______
> / \
> | __|_ | INFORMATION BELOW
>
> | ____| | for
> | ____| |
> | ____| | PAT's TUBE & RECORDING
> | ____| | °º¤ø SCHEMATICS ø¤º°
>
> |___| |____|
> [___________] please SCROLL DOWN, READ IT ALL.
> [___________] |
> [___________] |
> U U ___ U U \ /
> |__| '
>
>
>WEB TO--- http://nanaimo.ark.com/~pat/index.htm
>
>POSTAL ADDRESS:----
>
> PaT MorforD
> C8 Site28 RR2 Gabriola, BC Canada
> V0R-1X0
>
>ø¤ º°`°º¤ø,¸¸¸,ø¤º°`°º¤ø,¸¸¸,ø¤º°
>
>INFORMATION:
>
>-SCHEMATICS are EMAIL transfer, unless we arrange otherwise ahead of time
>-SCANS are sent .jpg, 200dpi, 256 grey scale, saved at 75% compression
> -you can view and print them with your browser, art program,etc..
> -please check your printer capabilities ahead of time
>
>PAYMENT :
>
>1: INTERNATIONAL postal order,
> or CASH in U.S.A. FUNDS !!!!!
>
> (cash in small amounts always gets through,
> DONT pay $20 to get a $5 PO..its NOT WORTH IT)
>
>2: I NEED a reminder of the schematics you wanted
> (40+ emails per day = 300ish/week = memory lapses)
>
>3: your EMAIL ADDRESS ...
> -make it readable, remember CASE is sensitive
> -please check your K limits for transfers.
>
>4: a SELF ADDRESSED ENVELOPE, or address sticker
>5: POSTAGE money, if we have to send by mail...
> -stamps from other countries ARENT usable from here.
> (and a SELF ADDRESSED ENVELOPE, or address sticker )
>
>(I also LOVE to get interesting STAMPS ,only as a record of
>the Web site interactions.....I am not a collector!)
>
>note:MUST BE INTERNATIONAL p.o. or CASH
>***I Can't accept ANY OTHER FORM OF PAYMENT*****
> -no personal cheques
> -no GOAT or magic beans...... ;-)
>
>
>ø¤ º°`°º¤ø,¸¸¸,ø¤º°`°º¤ø,¸¸¸,ø¤º°
>ø¤º°`°º¤ø,¸¸¸,ø¤º°
>
>
>
>
=========================================================================
From: evaguido <EvaGuido@iaehv.nl>
Subject: Re: [JN] 5687 line amp
Date: Wed, 19 Apr 2000 17:54:07 +0200
Source: Sound Digest Archive v02.n525
dear Pat,
you wrote:
>because smaller caps of a given material react faster.
Any idea why ?
>yes.
>i tend to drive ONE set.
(150 ohm headphones by the 5687 SRPP)
>actually, in my own setup, i use a 5751 and an output transformer..
Which transformes the voltage down ?
>but i
>was trying to come up with a CHEAP, EASY, versatile preamp that would use
>AVAILABLE stock of blaCK PLATE 5687'S.
OK
>other BLACK PLATE tubes, 5751, 6072, etc..arent really available as
>readily, or as cheaply...and the CULL RATE for maTCHING THEM, is aTTROCIOUS.
>( LIKE MY SPELLING)
>
>>>also, grounded CATHODE is stupid, in my opinion.
>>
>>Oh ?
>>
>>What is in the original cicrcuit (SRPP) looks like grounded cathode, no ?
>
>? WHAT CIRCUIT DO YOU MEAN?
The one you claim to be the owner of
>i have never put any grounded CATHODE CIRCUITS OUT THERE..
And what about the lower half of the SRPP circuit ? That is grounded
cathode......
>>>the cathode resistor acts as a fuSE in the case of a heater cathode short.
>>
>>That depends on the voltage in-between heater and ground, and the driving
>>impedance of that source. And then again, what is the difference with your
>>circuit ?
>
>NOT RELEVANT.
Yes, but given your reaction I think you do not understand what I trie to
explain
>i am not talking about the CIRCUIT values...
me neither
>i am talking about TUBE
>FAILURE, which can happen very definately by BLOWS to the unit, etc..
>or bad tubes in the first place, etc.
If a short between heater and cathode appears, several scenario are possible:
1 - Nothing happens, possibly due to referencing the heater with a relative
high impedance
2 - High currents start running, probably once one of the heater is fixed
to ground
>>I try to adapt my cicruits with respect to gain, in order to bennefit from
>>other advantages that I get once gain is reduced to the gain I need.
>
>as i said, i wasnt trying to make ThE BEST of anything,whatever that might
>be..
I don't disagree but before you mentionned not to be bothered by too much
gain. I only pointed out that I am careful with gain, that's all
>as i get older, i learn more and more how EASY it is to fool a human ..MP3
>is a prime example..
MP3 is coded according a certain algoritm and that can be heard....
its just a commercial compromise, no more
>most computer sound cards are doing a real world 30ish db s/n..
the bad ones probably, but usually it is not the card but the environment
and the way these PCs are assembled
>one of the REASONS people like tube gear is the slow response, i think, due
>to the output transformer..
Oh ? My 300b OPTX pts out 150 kHz and I still wonder if 50 kHz is sufficient
>no back EMF, like in a fast solid state amp..or rather LESS.
What do you mean here ?
>SO....i dont mind buildingthings like HEADPHONE amps with transformers
>these days......the LUNDAHL strip core sounds AMAZING.
Yes
regards
Guido
>ø¤ º°`°º¤ø,¸¸¸,ø¤º°`°º¤ø,¸¸¸,ø¤º°
>
> ______
> / \
> | __|_ | INFORMATION BELOW
>
> | ____| | for
> | ____| |
> | ____| | PAT's TUBE & RECORDING
> | ____| | °º¤ø SCHEMATICS ø¤º°
>
> |___| |____|
> [___________] please SCROLL DOWN, READ IT ALL.
> [___________] |
> [___________] |
> U U ___ U U \ /
> |__| '
>
>
>WEB TO--- http://nanaimo.ark.com/~pat/index.htm
>
>POSTAL ADDRESS:----
>
> PaT MorforD
> C8 Site28 RR2 Gabriola, BC Canada
> V0R-1X0
>
>ø¤ º°`°º¤ø,¸¸¸,ø¤º°`°º¤ø,¸¸¸,ø¤º°
>
>INFORMATION:
>
>-SCHEMATICS are EMAIL transfer, unless we arrange otherwise ahead of time
>-SCANS are sent .jpg, 200dpi, 256 grey scale, saved at 75% compression
> -you can view and print them with your browser, art program,etc..
> -please check your printer capabilities ahead of time
>
>PAYMENT :
>
>1: INTERNATIONAL postal order,
> or CASH in U.S.A. FUNDS !!!!!
>
> (cash in small amounts always gets through,
> DONT pay $20 to get a $5 PO..its NOT WORTH IT)
>
>2: I NEED a reminder of the schematics you wanted
> (40+ emails per day = 300ish/week = memory lapses)
>
>3: your EMAIL ADDRESS ...
> -make it readable, remember CASE is sensitive
> -please check your K limits for transfers.
>
>4: a SELF ADDRESSED ENVELOPE, or address sticker
>5: POSTAGE money, if we have to send by mail...
> -stamps from other countries ARENT usable from here.
> (and a SELF ADDRESSED ENVELOPE, or address sticker )
>
>(I also LOVE to get interesting STAMPS ,only as a record of
>the Web site interactions.....I am not a collector!)
>
>note:MUST BE INTERNATIONAL p.o. or CASH
>***I Can't accept ANY OTHER FORM OF PAYMENT*****
> -no personal cheques
> -no GOAT or magic beans...... ;-)
>
>
>ø¤ º°`°º¤ø,¸¸¸,ø¤º°`°º¤ø,¸¸¸,ø¤º°
>ø¤º°`°º¤ø,¸¸¸,ø¤º°
>
>
>
>
=========================================================================
From: "Gary E. Kaufman" <gkaufman@bu.edu>
Subject: [JN] 5687 Linestage - Help!!
Date: Thu, 9 Mar 2000 23:14:26 -0500
Source: Sound Digest Archive v02.n477
Ok, after an evening of hair pulling I'm ready to ask for some help!
I put together a version of Ralph Power's 5687 linestage (cap coupled) on
the xdrive. My power supply is quite different, but the linestage portion
is pretty true to the schematic. I regulated the power supply with a pair
of 0A2/0B2's, and used a 6X5 rectifier into 2.2uf, followed by a 20H choke,
into 200uf cerafine, 2K resistor then the regulator tubes.
It works very well and sounds great - here's the strange part. When I turn
the input all the way down it develops a moderate hum and becomes very
microphonic. Even one notch up (I'm using a cheapie stepped attenuator) and
it is dead quiet. I can turn to an unused input jack and it is dead quiet
at any setting except with the input grounded.
Have I inadvertently created a grounded grid amp? Any clues as to a
solution? I've hunted for a ground loop but can't spot one. I've floated
the ground on the stepped attenuator 100 ohms off ground without any
improvement. I've changed output caps. I've switched to shielded cable
between attenuator and grids. Argh...
- Gary
EMAIL: gkaufman@the-planet.org
Web: http://www.the-planet.org
=========================================================================
From: "Gary E. Kaufman" <gkaufman@bu.edu>
Subject: RE: [JN] 5687 Linestage - Help!!
Date: Fri, 10 Mar 2000 00:27:05 -0500
Source: Sound Digest Archive v02.n478
Small addendum -
Placing a .001uf cap across the input cures the problem! (Even a 220pf
mica did the trick although I only had one)
Wonder if it was oscillating?
- Gary
EMAIL: gkaufman@the-planet.org
Web: http://www.the-planet.org
> It works very well and sounds great - here's the strange part.
> When I turn
> the input all the way down it develops a moderate hum and becomes very
> microphonic. Even one notch up (I'm using a cheapie stepped
> attenuator) and
> it is dead quiet. I can turn to an unused input jack and it is dead quiet
> at any setting except with the input grounded.
=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: RE: [JN] 5687 Linestage - Help!!
Date: Fri, 10 Mar 2000 13:24:14 GMT
Source: Sound Digest Archive v02.n478
Gary,
>Placing a .001uf cap across the input cures the problem! (Even a 220pf
>mica did the trick although I only had one)
>
>Wonder if it was oscillating?
Yes, it was. Did you have either a Grid Stopper Resistor or a Ferrite Bead
on the Grig Pin of the Valve Socket? I'd recommend removing this 1nF
Capacitor as it will result in quite severe HF Rolloff at higher Volume
Level settings.
Later Thorsten
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
=========================================================================
From: "Gary E. Kaufman" <gkaufman@bu.edu>
Subject: [JN] 5687 Linestage on xdrive
Date: Sun, 5 Mar 2000 15:51:17 -0500
Source: Sound Digest Archive v02.n474
I was wondering who put the 5687 linestage on the XDRIVE?
I'd like to hear from anyone who has built this - I was going to toss it
together for fun.
- Gary
EMAIL: gkaufman@the-planet.org
Web: http://www.the-planet.org
=========================================================================
From: "Henry Platt" <hnplatt@massed.net>
Subject: Re: [JN] 5687 Linestage on xdrive
Date: Sun, 05 Mar 2000 22:31:07 -0800
Source: Sound Digest Archive v02.n475
Hi Gary,
try Paralleling the 5687 halves for lower output z, ala John L's 5687 pre
in Valve some time back. I built it and loved it.
Henry
- ----------
>From: "Gary E. Kaufman" <gkaufman@bu.edu>
>To: <sound@deliverator.io.com>
>Subject: [JN] 5687 Linestage on xdrive
>Date: Sun, Mar 5, 2000, 12:51 PM
>
> I was wondering who put the 5687 linestage on the XDRIVE?
>
> I'd like to hear from anyone who has built this - I was going to toss it
> together for fun.
>
> - Gary
>
> EMAIL: gkaufman@the-planet.org
> Web: http://www.the-planet.org
>
>
>
=========================================================================
From: "Dave Slagle" <dslagle@earthlink.net>
Subject: Re: [JN] 5687 Linestage on xdrive
Date: Mon, 06 Mar 2000 00:00:38 -0500
Source: Sound Digest Archive v02.n475
> Hi Gary,
> try Paralleling the 5687 halves for lower output z, ala John L's 5687 pre
> in Valve some time back. I built it and loved it.
> Henry
agreed....
all we want from a linestage is drive... and this does it... screw that oh
it blurs the sound BS...
look at a 5687 loesch linestage... it needs a 10K pot on the output...
paralel the 5687 and you need 5K that 50% reduction in resistance is far
better than any blurring you think you hear.... of course now you have to
whine about finding a high quality 5K pot...
dave
=========================================================================
From: "T. Loesch" <ezee_e@hotmail.com>
Subject: Re: [JN] 5687 Linestage on xdrive
Date: Mon, 06 Mar 2000 15:35:29 GMT
Source: Sound Digest Archive v02.n475
Hi there,
>I was wondering who put the 5687 linestage on the XDRIVE?
Not me.
>I'd like to hear from anyone who has built this - I was going to toss it
>together for fun.
I use something similar (the A. Loesch Linestage with 5687) as my main
linestage. Very good.
I also had a Schematic from Audio-Note Japan where both sections of the 5687
are tied together, 47k Anode Resistor, 1K Cathode Resistor (unbypassed) and
around 220V HT.... Heating AC.
This is one version of the M7 Linestage (the other uses 6072A in classic
Gainstage/Cathodefollower Combination), it is the lower gain one, but has a
very high Output Impedance (around 8K).
PSU BTW was very simple, RC only, with a 6X4 as rectifier and the classic
Audio-Note 500 Ohm, 100 uF, 2 kOhm, 100 uF PSU Filter. Then via another 2
kOhm, 100 uF Filter to each Channel. Capacitors are Elna Cerafine
100uF+100uF/350V.
Later Thorsten
______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com
=========================================================================
From: "Fred Volz" <fcv@emotiveaudio.com>
Subject: [JN] 5687 operating points
Date: Sun, 26 Sep 1999 00:04:27 -0400
Source: Sound Digest Archive v02.n286
Anyone care to comment on their favorite operating point for 5687s in a line
stage and why?
Fred Volz
fcv@emotiveaudio.com
=========================================================================
From: "David B. Klein" <dklein@microtec.net>
Subject: Re: [JN] 5687 operating points
Date: Sun, 26 Sep 1999 00:32:49
Source: Sound Digest Archive v02.n286
A 12:04 AM 9/26/99 -0400, Fred Volz a écrit :
>Anyone care to comment on their favorite operating point for 5687s in a line
>stage and why?
>
>Fred Volz
>fcv@emotiveaudio.com
>
>
>
Do you have a brother named Hi Volz? Is he AC/DC?
Best,
David
=========================================================================
From: "Fred Volz" <fcv@emotiveaudio.com>
Subject: Re: [JN] 5687 operating points
Date: Mon, 27 Sep 1999 00:05:28 -0400
Source: Sound Digest Archive v02.n286
- -----Original Message-----
From: David B. Klein <dklein@microtec.net>
To: Fred Volz <fcv@emotiveaudio.com>; Joelist <sound@deliverator.io.com>
Date: Sunday, September 26, 1999 1:19 AM
Subject: Re: [JN] 5687 operating points
>A 12:04 AM 9/26/99 -0400, Fred Volz a écrit :
>>Anyone care to comment on their favorite operating point for 5687s in a
line
>>stage and why?
>>
>>Fred Volz
>>fcv@emotiveaudio.com
>>
>>
>>
>Do you have a brother named Hi Volz? Is he AC/DC?
>
>Best,
>
>David
Ha ha! Yes.... That's really QUITE funny.... So, how DO you run a 5687 and
why?
The truth, by the way, is that: my uncle's initials are AC, My grandfather
was a professor of EE at Penn State, my father was a broadcast engineer and
is an electronics designer, and I have this little company that makes
preamps. For a while, I thought I could escape the name thing by studying
microbiology. But, my resolve was too weak. Did I mention that my folks
drove VWs when I was a kid. FOR YEARS! Square backs, Busses, Bugs... What
the hell were they thinking?
Fred Volz
fcv@emotiveaudio.com
=========================================================================
From: David Barnett <davidbarnett@aristotle.net>
Subject: Re: [JN] 5687 operating points
Date: Mon, 27 Sep 1999 10:11:28 -0500
Source: Sound Digest Archive v02.n286
On Mon, 27 Sep 1999 00:05:28 -0400, "Fred Volz" <fcv@emotiveaudio.com>
wrote:
>The truth, by the way, is that: my uncle's initials are AC, My grandfather
>was a professor of EE at Penn State, my father was a broadcast engineer and
>is an electronics designer, and I have this little company that makes
>preamps. For a while, I thought I could escape the name thing by studying
>microbiology. But, my resolve was too weak.
The Institute of Audio Research in NY used to have a receptionist
named Meg Hertz.
- --dnb
=========================================================================
From: "David B. Klein" <dklein@microtec.net>
Subject: Re: Sv: [JN] 5687 operating points
Date: Mon, 27 Sep 1999 16:37:59 -0700
Source: Sound Digest Archive v02.n287
Kurt Th. Steffensen wrote:
> >The Institute of Audio Research in NY used to have a receptionist
> >named Meg Hertz.
> >
> I think that before Davids , kleine joke about Volz , turns in to a contest , of names
> that is known for other things as well, I might as well take some of them here , and save us all a
little bandwidt.
>
> Cockburn. (Yup , its true )
But pronounced Co-burn, at least in the case of Bruce and other Canadians having that surname.
dbk
=========================================================================
From: David Barnett <davidbarnett@aristotle.net>
Subject: Re: Sv: [JN] 5687 operating points
Date: Mon, 27 Sep 1999 16:46:41 -0500
Source: Sound Digest Archive v02.n287
On Mon, 27 Sep 1999 21:54:09 +0300, "Kurt Th. Steffensen"
<kurt-steffensen@teliamail.dk> wrote:
>I think that before Davids , kleine joke about Volz , turns in to a contest , of names
>that is known for other things as well, I might as well take some of them here , and save us all a
little bandwidt.
Preemptive strike?
Yeah, since our units of measurement are all named after the pioneers
of their respective fields of science, it stands to reason that there
will be people with these names.
- --dnb
=========================================================================
From: "David B. Klein" <dklein@microtec.net>
Subject: Re: Sv: [JN] 5687 operating points
Date: Mon, 27 Sep 1999 16:53:27
Source: Sound Digest Archive v02.n287
A 09:54 PM 9/27/99 +0300, Kurt Th. Steffensen a écrit :
>
>>
>Klein (Meins little in Danish as well in German )
Those of us who do hands-on electronic work are all familiar with Klein
Tools. Mine? I'm not telling.
dbk
=========================================================================
From: "David B. Klein" <dklein@microtec.net>
Subject: Re: Sv: [JN] 5687 operating points
Date: Mon, 27 Sep 1999 18:38:58
Source: Sound Digest Archive v02.n287
A 04:46 PM 9/27/99 -0500, David Barnett a écrit :
since our units of measurement are all named after the pioneers
>of their respective fields of science, it stands to reason that there
>will be people with these names.
But the unit of electrical potential was named after Alessandro Volta
(1745-1827).
dbk
=========================================================================
From: Rick Francis <rfrancis@glasscity.net>
Subject: [JN] Re: 5687 operating points
Date: Mon, 27 Sep 1999 18:55:20 -0400
Source: Sound Digest Archive v02.n287
Well since no one else has mentioned it, the article on Steve Berger's
MV-45 amp in a recent Sound Practices issue mentions that he calculated
nice linear operating points for the 5687 from the curves. His amp uses
the tube in two stages before the parallel 45 or single 2A3.
I just painted a PT and choke to build this amp using FS-030 iron. If I
weren't having so much fun goofin' with my 3.5 month old son, I'd
probably finish it soon.
It's the first time I ever used wrinkle paint -- some stuff from an auto
store. It works GREAT! I can't believe how professional it worked the
FIRST TIME. Took me a few tries to get the hang of Hammerite.
- --Rick
=========================================================================
From: "Kurt Th. Steffensen" <kurt-steffensen@teliamail.dk>
Subject: Sv: [JN] 5687 operating points
Date: Mon, 27 Sep 1999 21:54:09 +0300
Source: Sound Digest Archive v02.n287
>The Institute of Audio Research in NY used to have a receptionist
>named Meg Hertz.
>
Amazing ....
You mean as in Mega Hertz ?
I think that before Davids , kleine joke about Volz , turns in to a contest , of names
that is known for other things as well, I might as well take some of them here , and save us all a l
ittle bandwidt.
The following are person names in Europe:
Henry
Volt
Ampere
Hertz
Klein (Meins little in Danish as well in German )
Ohm
Winter
Summer
Baker
Mcintosh
Miller
Zeppelin
Farad
Faraday (faraway ? )
Jensen (for the cars)
Jensen (for the speakers)
Hasselblad
P. Nut
Engstroem
Maxwell
King
Prince
Apple
Philips
Post
Mercedes
Mullard
Brown
Black
Red
Blue
White
Whitehouse
Swartch
Cockburn. (Yup , its true )
Wargrave !!
Lillienthal (Thats my middle name. Yes , I am in family with THAT Otto , it means
lily dale )
Rosenthal means Rosen dale
Bloomen dale means Flower dale.
(Do you get it ? )
Chippen dale means ridiculas......
Oh , I allmost forgot Watt , Colt , Nobel , Bang (means bom )
Jan (Joint Arm Navy ? )
Not to forget all the French´s Camembert , Cognac , Champagne ,
etc.etc
(Camembert electrique is a outstanding album by a fabolous French group
called "GONG".....Yes, this is actually true as well , though I doubt , many americans
or any others outside our continent , knows this terrifict band )
I know a electronic engineer that is named: El Strøm.
EL means electricity in Danish.
Strøm means current.
When I was a young kid , I had a summer job ,bringing out some post , to private houses.
One reciever had the name A.Hitler on the door.
My fantasy just went crazy , and I had to ring the door bell , to check it out.
I promised to keep it a secret , whom the person actually was.
- - Kurt Langkaster (Very , very - - - `jolly good , funny Danish joke about my name )
Well , to get back to the real issue about 5687 operating points ,
(Sorry , for all the babble , Fred )
The manual suggest:
250 V , - 12,5V , =12mA , Ri 3000 , u 16
180 V , - 7V = 23ma , Ri 2000 , u 17.
When I use 5687 , I am close to these , depending on the purpose and surrounding
circuits.
If you go for that , you only need to fine tune the anode resistor and cathode resistor with
10-20 % to get the optimal point , in your circuit.
Fred as a Danish name , means Peace....
Allright , I will stop now.
- - Kurt
=========================================================================
From: "Fred Volz" <fcv@emotiveaudio.com>
Subject: Re: Sv: [JN] 5687 operating points
Date: Tue, 28 Sep 1999 02:21:38 -0400
Source: Sound Digest Archive v02.n288
- -----Original Message-----
From: David B. Klein <dklein@microtec.net>
To: Kurt Th. Steffensen <kurt-steffensen@teliamail.dk>
Cc: David Barnett <davidbarnett@aristotle.net>; sound@lists.io.com
<sound@lists.io.com>
Date: Monday, September 27, 1999 5:43 PM
Subject: Re: Sv: [JN] 5687 operating points
>> Cockburn. (Yup , its true )
>
>But pronounced Co-burn, at least in the case of Bruce and other Canadians
having that surname.
>
>dbk
>
When I was a young lad of, perhaps, 17, I learned the proper pronunciation
of the name Cockburn. This education came to me while meeting with the
program director of the radio station where I worked as an announcer. We
were going over the air check of my previous night's shift (probably my
third or fourth time on the air). I had been playing "Wondering Where The
Lions Are" when I realized I would have to announce the artist's name. Did I
mention that I was 17? Anyway, after giving the subject some thought, I
stammered the name just as it was printed with the exception that I made it
sound like each syllable was its own word--with special attention given to
the first syllable. I was really an exceptionally bad DJ in those early
days. But, I can honestly say that after a few years of hard work I was
merely terrible.
Fred Volz
fcv@emotiveaudio.com
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] 5687 operating points
Date: Tue, 28 Sep 1999 10:54:04 -0400
Source: Sound Digest Archive v02.n288
At 12:04 AM -0400 9/26/99, Fred Volz wrote:
>Anyone care to comment on their favorite operating point for 5687s in a line
>stage and why?
I very much prefer this tube at 250Vp, -12 volts bias and 12mA. I don't
like the lower, hotter operating points--it gets too analytical for my
taste.
Grover Gardner
groverg@postoffice.att.net
=========================================================================
From: "Fred Volz" <fcv@emotiveaudio.com>
Subject: Re: [JN] 5687 operating points
Date: Wed, 29 Sep 1999 03:08:09 -0400
Source: Sound Digest Archive v02.n288
Thanks to all who replied to my query about 5687 operating points; your help
is very much appreciated.
Our initial investigations with this tube simply swapped them into an older
circuit designed around 27s (130 V plate at 5 ma)--settings not really even
ideal for the 27s. We realized that these numbers would, likely, not hold
but wanted an easy starting point to see what the 5687s and a bunch of other
tubes sounded like in general. It may also be worth pointing out that the
circuit we used for our listening tests uses transistor current sources for
both the plate of the voltage amplifier and the cathode of the cathode
follower. The roughly 130-150 Volt plate was maintained be adjusting the
number of series LEDs used to set bias. There were a lot of tubes we liked
and some that, not surprisingly, we did not like. Metal 6L6s sound pretty
decent triode connected in a line stage. I also really liked 10s but they
would be next to impossible to implement. Ultimately, our top three
favorites were (in no particular order) 27s, 30s, and 5687s. Tubes that we
liked much less included 6DJ8s, 12A*7s, 12BH7s, and a whole bunch more.
While these tubes weren't actually bad sounding, they had no magic. If
anyone is interested in the complete list of tubes we listened to (albeit,
at non-optimized operating points), let me know and I can e-mail you our
notes.
So, we have, somewhat anacronistically, discovered that the 5687 is a very
good voltage amplifier! We will now look forward to trying some of the
suggested operating points to find what works best for us.
Fred Volz
fcv@emotiveaudio.com
=========================================================================
From: "Richard Jones" <RJ0101@Sprynet.Com>
Subject: [JN] 5687 op point
Date: Wed, 14 Apr 1999 22:42:18 -0500
Source: Sound Digest Archive v02.n124
This is a multi-part message in MIME format.
- ------=_NextPart_000_0004_01BE86C8.0D6A3D00
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Well i tried the 100v 10ma vs the 200v 10ma points and i kinda like the =
100v 10mA point better. Grover, i am wondering whether my transformer =
load has something to do with it... or perhaps it is the cathode =
resistors as i am comparing a tantalum film resistor to a non-inductive =
wirewound.
ideas... thoughts?
also how hard is it to drive a 50? and are there any cheaper tubes that =
sound like the 45,50 type but have the 4-5 watts output? (besides 300B)?
txs in advance.
- ------=_NextPart_000_0004_01BE86C8.0D6A3D00
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
<HTML>
<HEAD>
<META content=3Dtext/html;charset=3Diso-8859-1 =
http-equiv=3DContent-Type>
<META content=3D'"MSHTML 4.72.2106.6"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT color=3D#000000 size=3D2>Well i tried the 100v 10ma vs the =
200v 10ma=20
points and i kinda like the 100v 10mA point better. Grover, i am =
wondering=20
whether my transformer load has something to do with it... or perhaps it =
is the=20
cathode resistors as i am comparing a tantalum film resistor to a =
non-inductive=20
wirewound.</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>ideas... thoughts?</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>also how hard is it to drive a 50? =
and are there=20
any cheaper tubes that sound like the 45,50 type but have the 4-5 watts =
output?=20
(besides 300B)?</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>txs in =
advance.</FONT></DIV></BODY></HTML>
- ------=_NextPart_000_0004_01BE86C8.0D6A3D00--
=========================================================================
From: Timo Christ <carnivor@uni-bremen.de>
Subject: [JN] 5687 run-away ?
Date: Mon, 14 Aug 2000 22:32:02 +0200
Source: Sound Digest Archive v02.n627
Hi Joes,
i have a mysterious problem with one channel of my one-tube 5687 amp.
The power section draws more and more current (increases with time).
The current should be 20mA, but is 30mA at switch-on already and then
increases.
I noticed it because the sound was bad (which i attributed to a preamp
problem first) but at night i saw the anode glowing... ouch.
The cathode bias (R // C) seems OK, 8V. I swapped the bias cap but the
problem remains.
Driver stage doesn't seem to have a problem.
It is no bad tube either, i swapped it and the problem is exactly the
same.
Trannie DCR is exactly the same as on the other channel.
No shorts on the socket either. The current is pulled through the poor
trannie, which became quite hot.
I have no real idea about it.
Do you have a clue? Please ?
The schematic:
http://www-user.uni-bremen.de/~carnivor/5687se/5687schemo.jpg
Regards
Timo
- --
/ /--' Timo Christ carnivore@uni-bremen.de
/ /<-. EE Student University of Bremen, Germany
__/ /__/ Horns 'r more fun:
' http://www-user.uni-bremen.de/~carnivor/
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] 5687 run-away ?
Date: Mon, 14 Aug 2000 17:06:54 -0400
Source: Sound Digest Archive v02.n628
hi timo,
this happened to me when i first built my pp5687 power amp.
the problem is due to grid emission at the relatively high plate dissipation
levels we're using to make this into a power amp.
grid emission initiates negative grid current (flowing out of the grid into
the grid resistor).
the grid current causes a positive voltage to develop at the grid
which counters the cathode bias.
this leads to higher plate current
which leads to higher plate dissipation
which leads to higher grid emission current
which leads to decreased negative bias
which leads to higher plate current
etc
etc
so you get a thermal runaway...
i have found that you need a grid resistor of <100K
for about 3W of plate dissipation.
less is better.
and if you're using a 5687 to drive the 5687, you could
easily afford a 20K to 33K grid resistor...
BTW: that is a very interesting bias/coupling arrangement
you have on the input stage.
what type of Li battery are you using?
i'd be equally afraid of grid emission into that battery
if it is a coin-cell. they tend to act as popcorn if they
see the faintest of charge currents.... ;)
the limiting resistance will probably keep you safe....
have fun,
bob.d.
> ----------
> From: Timo Christ[SMTP:carnivor@uni-bremen.de]
> Reply To: carnivore@uni-bremen.de
> Sent: Monday, August 14, 2000 4:32 PM
> To: Joe-Net
> Subject: [JN] 5687 run-away ?
>
> Hi Joes,
>
> i have a mysterious problem with one channel of my one-tube 5687 amp.
> The power section draws more and more current (increases with time).
> The current should be 20mA, but is 30mA at switch-on already and then
> increases.
> I noticed it because the sound was bad (which i attributed to a preamp
> problem first) but at night i saw the anode glowing... ouch.
> The cathode bias (R // C) seems OK, 8V. I swapped the bias cap but the
> problem remains.
> Driver stage doesn't seem to have a problem.
> It is no bad tube either, i swapped it and the problem is exactly the
> same.
> Trannie DCR is exactly the same as on the other channel.
> No shorts on the socket either. The current is pulled through the poor
> trannie, which became quite hot.
>
> I have no real idea about it.
>
> Do you have a clue? Please ?
>
> The schematic:
> http://www-user.uni-bremen.de/~carnivor/5687se/5687schemo.jpg
>
> Regards
> Timo
> --
> / /--' Timo Christ carnivore@uni-bremen.de
> / /<-. EE Student University of Bremen, Germany
> __/ /__/ Horns 'r more fun:
> ' http://www-user.uni-bremen.de/~carnivor/
>
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] 5687 run-away ?
Date: Mon, 14 Aug 2000 19:16:41 -0400
Source: Sound Digest Archive v02.n628
you may have done some damage to the tube.
that's why it continues to run away.
keep the grid resistor under 100K.
replace the tube, and see if it still happens.
or swap the tubes channel to channel.
you may also have a poor connection grid to ground somewhere...
good luck,
bob.d
> ----------
> From: Timo Christ[SMTP:carnivor@uni-bremen.de]
> Reply To: carnivore@uni-bremen.de
> Sent: Monday, August 14, 2000 7:04 PM
> To: Danielak, Robert M; Joe-Net
> Subject: Re: [JN] 5687 run-away ?
>
> Hi Bob D., Joes,
>
> thanks for your help.
>
> > this happened to me when i first built my pp5687 power amp.
> >
> > the problem is due to grid emission at the relatively high plate
> dissipation
> > levels we're using to make this into a power amp.
> >
> > grid emission initiates negative grid current (flowing out of the grid
> into
> > the grid resistor).
> > the grid current causes a positive voltage to develop at the grid
> > which counters the cathode bias.
> > this leads to higher plate current
> > which leads to higher plate dissipation
> > which leads to higher grid emission current
> > which leads to decreased negative bias
> > which leads to higher plate current
> > etc
> > etc
> >
> > so you get a thermal runaway...
>
> Aha!
>
> > i have found that you need a grid resistor of <100K
> > for about 3W of plate dissipation.
> >
> > less is better.
> > and if you're using a 5687 to drive the 5687, you could
> > easily afford a 20K to 33K grid resistor...
>
>
> Hmm, ok, changed the 220 k to 50k. Runaway is now slower, but not
> stopped.
> Brutal to 15 k. It is crawling now, but steadily upwards. Stopped it at
> 35mA.
>
> What now? Drop to 10k would make the driver stage work pretty hard.
>
> > BTW: that is a very interesting bias/coupling arrangement
> > you have on the input stage.
>
> Manfred's idea.
>
> > what type of Li battery are you using?
>
> BR 2032.
> 3V, 190mAh, Poly-Carbonmonofluorid.
>
> > i'd be equally afraid of grid emission into that battery
> > if it is a coin-cell. they tend to act as popcorn if they
> > see the faintest of charge currents.... ;)
>
> the batteries are still alife.
>
> > the limiting resistance will probably keep you safe....
>
> Hope so...
>
> The amp is scheduled for rebuild into a more compact 6C45Pi amp anyway,
> with integral power supply, maybe regulated.
> Still, i would like to get it up and running again because i have no
> time for this rebuild now. After all, the other channel works with the
> 220k grid resistor. The now defective channel has worked for hundreds of
> hours as well before it developed this fault. How come?
>
> Best Regards
> Timo
> --
> / /--' Timo Christ carnivore@uni-bremen.de
> / /<-. EE Student University of Bremen, Germany
> __/ /__/ Horns 'r more fun:
> ' http://www-user.uni-bremen.de/~carnivor/
>
=========================================================================
From: tube@jump.net
Subject: Re: [JN] 5687 run-away ?
Date: Mon, 14 Aug 2000 20:07:34 -0500
Source: Sound Digest Archive v02.n628
Timo Christ wrote:
> Hi Bob D., Joes,
>
> > so you get a thermal runaway...
>
> Aha!
>
> Hmm, ok, changed the 220 k to 50k. Runaway is now slower, but not
> stopped.
> Brutal to 15 k. It is crawling now, but steadily upwards. Stopped it at
> 35mA.
>
> What now? Drop to 10k would make the driver stage work pretty hard.
Just as a pure guess, maybe you could lower the heater voltage some?
This is obviously another major source of heat near the grid, and I know
many tubes are actually "over-heated" when new, the idea being that as
the years pass and emission goes down, there will still be plenty of
emission due the the slightly excess heat from the heater. Especially in
linear operations, there really is no need for the tube to be handle high
current pulses. I think the 5687 was designed to do just this.
Phil
> Best Regards
> Timo
> --
> / /--' Timo Christ carnivore@uni-bremen.de
> / /<-. EE Student University of Bremen, Germany
> __/ /__/ Horns 'r more fun:
> ' http://www-user.uni-bremen.de/~carnivor/
=========================================================================
From: tube@jump.net
Subject: Re: [JN] 5687 run-away ?
Date: Mon, 14 Aug 2000 20:16:01 -0500
Source: Sound Digest Archive v02.n628
"Danielak, Robert M" wrote:
> you may have done some damage to the tube.
> that's why it continues to run away.
>
> keep the grid resistor under 100K.
> replace the tube, and see if it still happens.
>
> or swap the tubes channel to channel.
>
> you may also have a poor connection grid to ground somewhere...
>
> good luck,
>
> bob.d
Now there's a very interesting thought! Now that you mention it, I
remember reading that high cathode temperatures can cause some
of the oxide to deposit on the grid, where it immediately causes grid
emission and thermal runaway.
Maybe both Timo and "the other guy", whose Flesh and Blood amp
keeps killing 6SN7's, have heaters just a little too high (with high
plate dissipation you don't need as much heater power anyway),
and it's causing oxide to get on the grids.
Hey maybe not, but it's an interesting possibility!
Phil
=========================================================================
From: "PEARL Cust Serv" <custserv@pearl-hifi.com>
Subject: Re: [JN] 5687 run-away ?
Date: Mon, 14 Aug 2000 20:30:20 -0600
Source: Sound Digest Archive v02.n628
Phil tube@jump.net wrote
> "Danielak, Robert M" wrote:
>
>> you may have done some damage to the tube.
>> that's why it continues to run away.
>>
>> keep the grid resistor under 100K.
>> replace the tube, and see if it still happens.
>>
>> or swap the tubes channel to channel.
>>
>> you may also have a poor connection grid to ground somewhere...
>>
>> good luck,
>>
>> bob.d
>
> Now there's a very interesting thought! Now that you mention it, I
> remember reading that high cathode temperatures can cause some
> of the oxide to deposit on the grid, where it immediately causes grid
> emission and thermal runaway.
SNIP
> Phil
Sometimes . . and *only& sometimes this can be cured by clamping the
current allowed to flow thru the tube and cranking it's heater voltage to
200% of nominal for 1 min. This can "blow" any cathode coating mtl from the
gird and onto the plate . . .
It's an interesting effect and worth a try . . . .
Bill - PEARL, Inc.
=========================================================================
From: Timo Christ <carnivor@uni-bremen.de>
Subject: Re: [JN] 5687 run-away ?
Date: Tue, 15 Aug 2000 01:04:47 +0200
Source: Sound Digest Archive v02.n628
Hi Bob D., Joes,
thanks for your help.
> this happened to me when i first built my pp5687 power amp.
>
> the problem is due to grid emission at the relatively high plate dissipation
> levels we're using to make this into a power amp.
>
> grid emission initiates negative grid current (flowing out of the grid into
> the grid resistor).
> the grid current causes a positive voltage to develop at the grid
> which counters the cathode bias.
> this leads to higher plate current
> which leads to higher plate dissipation
> which leads to higher grid emission current
> which leads to decreased negative bias
> which leads to higher plate current
> etc
> etc
>
> so you get a thermal runaway...
Aha!
> i have found that you need a grid resistor of <100K
> for about 3W of plate dissipation.
>
> less is better.
> and if you're using a 5687 to drive the 5687, you could
> easily afford a 20K to 33K grid resistor...
Hmm, ok, changed the 220 k to 50k. Runaway is now slower, but not
stopped.
Brutal to 15 k. It is crawling now, but steadily upwards. Stopped it at
35mA.
What now? Drop to 10k would make the driver stage work pretty hard.
> BTW: that is a very interesting bias/coupling arrangement
> you have on the input stage.
Manfred's idea.
> what type of Li battery are you using?
BR 2032.
3V, 190mAh, Poly-Carbonmonofluorid.
> i'd be equally afraid of grid emission into that battery
> if it is a coin-cell. they tend to act as popcorn if they
> see the faintest of charge currents.... ;)
the batteries are still alife.
> the limiting resistance will probably keep you safe....
Hope so...
The amp is scheduled for rebuild into a more compact 6C45Pi amp anyway,
with integral power supply, maybe regulated.
Still, i would like to get it up and running again because i have no
time for this rebuild now. After all, the other channel works with the
220k grid resistor. The now defective channel has worked for hundreds of
hours as well before it developed this fault. How come?
Best Regards
Timo
- --
/ /--' Timo Christ carnivore@uni-bremen.de
/ /<-. EE Student University of Bremen, Germany
__/ /__/ Horns 'r more fun:
' http://www-user.uni-bremen.de/~carnivor/
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] 5687 run-away ?
Date: Tue, 15 Aug 2000 09:14:07 -0400
Source: Sound Digest Archive v02.n628
whatever the mechanism, i've done this to both 5687's and 1626's.
once they went into thermal runaway, they were never the same.
i had to toss the tube. even in a "fixed" circuit they continued to runaway.
(well, of course, i didn't throw them away. i use them as "display" items at
work...)
pack-rat,
bob.d.
> ----------
> From: tube@jump.net[SMTP:tube@jump.net]
> Sent: Monday, August 14, 2000 9:16 PM
> To: Danielak, Robert M
> Cc: Joe-Net; 'carnivore@uni-bremen.de'
> Subject: Re: [JN] 5687 run-away ?
>
> "Danielak, Robert M" wrote:
>
> > you may have done some damage to the tube.
> > that's why it continues to run away.
> >
> > keep the grid resistor under 100K.
> > replace the tube, and see if it still happens.
> >
> > or swap the tubes channel to channel.
> >
> > you may also have a poor connection grid to ground somewhere...
> >
> > good luck,
> >
> > bob.d
>
> Now there's a very interesting thought! Now that you mention it, I
> remember reading that high cathode temperatures can cause some
> of the oxide to deposit on the grid, where it immediately causes grid
> emission and thermal runaway.
>
> Maybe both Timo and "the other guy", whose Flesh and Blood amp
> keeps killing 6SN7's, have heaters just a little too high (with high
> plate dissipation you don't need as much heater power anyway),
> and it's causing oxide to get on the grids.
>
> Hey maybe not, but it's an interesting possibility!
>
> Phil
>
>
=========================================================================
From: Timo Christ <carnivor@uni-bremen.de>
Subject: [JN] 5687 SE Tube amp photos
Date: Sat, 13 May 2000 17:26:43 +0200
Source: Sound Digest Archive v02.n545
Hello Everyone,
just a short note that photos of my new 5687 SE tube amplifier are now
online.
Please see this address:
http://www-user.uni-bremen.de/~carnivor/5687se/5687se.html
Best Regards,
Timo
- --
____
/ __ \ Timo Christ carnivore@uni-bremen.de
|....| EE Student University of Bremen, Germany
\_/\_/ Horns 'r more fun:
|||| http://www-user.uni-bremen.de/~carnivor/
=========================================================================
From: Timo Christ <carnivor@uni-bremen.de>
Subject: [JN] 5687 SPUD ENERGIZED
Date: Sat, 13 May 2000 13:02:10 +0200
Source: Sound Digest Archive v02.n544
HI ALL!
I'm thrilled to tell that my first tube amp is now in operation.
First, let me thank each of you who helped with this project, especially
the designer of the amp Manfred Huber. Additional thanks go to the
people who helped with parts, you know who you are :-).
Now, it is a one-tube amplifier, using a 5687 per channel. One triode
system is used to drive the other. The first stage is battery biased
(3V), the output stage resistor/bypassed biased. I am using Sowter SE02
OPTs.
Power output is supposed to be 0.5W but i didn't measure it.
The power supply is 100 % MKP filterd, with about 600uF.
This PSU is external, the heater supply of 12,6V AC is external as well.
There are local PS decoupling caps inside the amp of 120uF.
Surely you would like to know how it sounds? Well, it sounds fine. In
comparison to my solid-state amps (TDA2050 "47labs", 0.6W BJT-SE) it has
the same dynamic capabilites, cleanliness and ability to make the music
sound real. I do not feel that it is colored in any way. However, there
is a new sense of "space" within the reproduction.
But you need to give me more time to get into it, i just finished the
amp an hour ago.
Photos and a schematic will be on my website soon.
Thanks and Good Sound to all of you,
Timo
- --
____
/ __ \ Timo Christ carnivore@uni-bremen.de
|....| EE Student University of Bremen, Germany
\_/\_/ Horns 'r more fun:
|||| http://www-user.uni-bremen.de/~carnivor/
=========================================================================
From: MHuber@t-online.de (Manfred Huber)
Subject: Re: [JN] 5687 SPUD ENERGIZED
Date: Sat, 13 May 2000 21:02:05 +0200
Source: Sound Digest Archive v02.n545
Timo,
>I'm thrilled to tell that my first tube amp is now in operation.
Congratulations on your first tube amp! I had a look at your pictures
and was very inpressed with the implementation. Shame on me. After more then
three years of tube amp building I'm still toying around with my breadboards...
Poor guy, now that you are infected you will not be able to stop building
tube amps. <g>
>especially the designer of the amp Manfred Huber.
Thanks for the appreciation, but I honestly think it is as at least much
your design as it is mine. I was merely tossing in a battery and crunching a few numbers
Regards
Manfred
- ------------------
Manfred Huber
MHuber@t-online.de
- ------------------
=========================================================================
From: Timo Christ <carnivor@uni-bremen.de>
Subject: Re: [JN] 5687 SPUD ENERGIZED
Date: Mon, 15 May 2000 22:37:47 +0200
Source: Sound Digest Archive v02.n546
Hi All, Manfred,
> >I'm thrilled to tell that my first tube amp is now in operation.
>
> Congratulations on your first tube amp! I had a look at your pictures
> and was very inpressed with the implementation. Shame on me. After more then
> three years of tube amp building I'm still toying around with my breadboards...
But you are actually developing new circuits. Most of the stuff that i
build are other designs tossed together and adjusted to my parts values.
:-)
> Poor guy, now that you are infected you will not be able to stop building
> tube amps. <g>
Yea right. :-)
The next project is a hybrid amp with a paralleled 5687 @300V/25mA
driver (Hello Hugh!) and John Linsley Hood 1969 NPN output stage.
The power supply is actually already on the workbench.
This amp will rock :-) ! I know that i like this output stage (very
similar to my "Battleship" amp) and i got enough lovely 5687s to try in
the voltage amp thanks to the Donation (!) by Kurt Steffensen, and a
trade with Allen Wright.
Thank you guys!
> >especially the designer of the amp Manfred Huber.
>
> Thanks for the appreciation, but I honestly think it is as at least much
> your design as it is mine. I was merely tossing in a battery and crunching a few
> numbers
Well, ok. Let's call it a fruitful cooperation :-).
Fact is that this amp would not exist without you.
I just put the schematic and some nice "glow" pics online.
http://www-user.uni-bremen.de/~carnivor/5687se/5687se.html
See you later
and thanks for all the support!
glowing Timo
- --
____
/ __ \ Timo Christ carnivore@uni-bremen.de
|....| EE Student University of Bremen, Germany
\_/\_/ Horns 'r more fun:
|||| http://www-user.uni-bremen.de/~carnivor/
=========================================================================
From: "Geoffrey Barre" <ael34@magma.ca>
Subject: [JN] 5687s to swap
Date: Sat, 15 Sep 2001 20:20:22 -0400
Source: Sound Digest Archive v02.n975
I was recently given a box of "old" tubes, lots of dual triodes etc. Among
them are 18 5687s, 7 of which are Sylvania Gold Brand with gold pins. I'd be
interested in swapping some of them, if anyone's interested (if not, they'll
go on Ebay). The others are RCAs and Marconis, some of which have what I can
only describe as "mottled" plates bronze in color with some patchy black
bits. Anyone ever come across this before?
/geoff
=========================================================================
From: "Jim Dudley" <jimd@polaris.net>
Subject: [JN] 5687 vs 5842
Date: Wed, 27 Dec 2000 22:11:52 -0500
Source: Sound Digest Archive v02.n771
This is a multi-part message in MIME format.
- ------=_NextPart_000_0050_01C07052.0430A560
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Opinions wanted:
How do the above 2 tubes differ in sound flavor sitting in the driver =
seat of a 300B IT coupled amp? I'm assuming the 5687 stages are direct =
coupled aka Steve Berger's Bronze 50. My breadboarded amps are =
impatiently waiting for a new driver.......
Thanks,
Jim Dudley
- ------=_NextPart_000_0050_01C07052.0430A560
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD W3 HTML//EN">
<HTML>
<HEAD>
<META content=3Dtext/html;charset=3Diso-8859-1 =
http-equiv=3DContent-Type>
<META content=3D'"MSHTML 4.72.3110.7"' name=3DGENERATOR>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT size=3D2>Opinions wanted:</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>How do the above 2 tubes differ in =
sound flavor=20
sitting in the driver seat of a 300</FONT><FONT color=3D#000000 =
size=3D2>B IT=20
coupled amp? I'm assuming the 5687 stages are direct coupled aka =
Steve=20
Berger's Bronze 50. My breadboarded amps are impatiently waiting =
for a new=20
driver.......</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>Thanks,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2>Jim =
Dudley</FONT></DIV></BODY></HTML>
- ------=_NextPart_000_0050_01C07052.0430A560--
=========================================================================
From: Allen Wright <AllenVSE@compuserve.com>
Subject: [JN] 5687 vs 5842
Date: Thu, 28 Dec 2000 05:39:41 -0500
Source: Sound Digest Archive v02.n771
Jim asked:
>>>Opinions wanted: How do the above 2 tubes differ in sound flavor...My
breadboarded amps are impatiently waiting for a new driver.......<<<
Jim, why not try both yourself, and report back? With the experimenters
luxury of a breadboard setup, you are in the prime position to test this
out - quickly and relatively easily - and then you will have first hand
knowledge for yourself in _your_ system.
Your opinion is more than valid and I'm sure we would all be interested in
what you experience.
I say "Go for it!"
Allen (VSE)
=========================================================================
From: John Levreault <jlevro@mediaone.net>
Subject: Re: [JN] 5687 vs 5842
Date: Thu, 28 Dec 2000 09:31:22 -0500
Source: Sound Digest Archive v02.n771
> Jim Dudley wrote:
>
> Opinions wanted:
> How do the above 2 tubes differ in sound flavor sitting in the driver
> seat of a 300B IT coupled amp? I'm assuming the 5687 stages are
> direct coupled aka Steve Berger's Bronze 50. My breadboarded amps are
> impatiently waiting for a new driver.......
I recently implemented the Bronze 50 driver stage with a 300B/FS030.
Pentode boy has been converted. As I've said many times, though, avoid
those junky JAN Philips 5687's and go for some GE's or RCA's.
I know there are many on this list who believe otherwise, but IME a 5842
simply can't drive a 300B to full output, unless of course it's running
off a 250V supply, but then you'd be using a 2A3, right? Even then, it's
marginal at best. I highly value dynamic headroom in my driver stage,
and the 5842 just doesn't have it. IIRC, though, Slagle has had some
success with grid chokes so the onset of that dreaded grid current is
delayed, providing more output swing.
IMO, the 5842 makes a great battery-biased transformer-coupled line
stage if you need a lot of gain.
JL
=========================================================================
From: John Levreault <jlevro@mediaone.net>
Subject: Re: [JN] 5687 vs 5842
Date: Thu, 28 Dec 2000 09:32:46 -0500
Source: Sound Digest Archive v02.n771
Allen Wright wrote:
>
> Jim asked:
>
> >>>Opinions wanted: How do the above 2 tubes differ in sound flavor...My
> breadboarded amps are impatiently waiting for a new driver.......<<<
>
> Jim, why not try both yourself, and report back? With the experimenters
> luxury of a breadboard setup, you are in the prime position to test this
> out - quickly and relatively easily - and then you will have first hand
> knowledge for yourself in _your_ system.
>
> Your opinion is more than valid and I'm sure we would all be interested in
> what you experience.
>
> I say "Go for it!"
Allen's (W)right, of course. My opinionated rantings to the contrary,
only YOU can answer the question. At least the 2 tubes use the same
socket.
JL
>
> Allen (VSE)
=========================================================================
From: "Jim Dudley" <jimd@polaris.net>
Subject: Re: [JN] 5687 vs 5842
Date: Thu, 28 Dec 2000 11:54:42 -0500
Source: Sound Digest Archive v02.n771
Thanks folks for the input! I was looking for some opinions on how their
sound differs but I got some good advice anyway. You guys know how to
sniff out lazy! Based on great success with JL's 5687 linestage and SB's
input I plan to start with Steve's coupled 5687 driver design. I'm already
familar with the 5842 in this position. Hope to offer more later.
Jim Dudley
- -----Original Message-----
From: Allen Wright <AllenVSE@compuserve.com>
To: AAJoeNet <sound@lists.io.com>
Date: Thursday, December 28, 2000 5:59 AM
Subject: [JN] 5687 vs 5842
>Jim asked:
>
>>>>Opinions wanted: How do the above 2 tubes differ in sound flavor...My
>breadboarded amps are impatiently waiting for a new driver.......<<<
>
>Jim, why not try both yourself, and report back? With the experimenters
>luxury of a breadboard setup, you are in the prime position to test this
>out - quickly and relatively easily - and then you will have first hand
>knowledge for yourself in _your_ system.
>
>Your opinion is more than valid and I'm sure we would all be interested in
>what you experience.
>
>I say "Go for it!"
>
>Allen (VSE)
>
>
>
=========================================================================
From: "Andy Evans" <arts.psychology@cwcom.net>
Subject: Re: [JN] 5687 vs 5842
Date: Thu, 28 Dec 2000 17:56:32 -0000
Source: Sound Digest Archive v02.n771
It's often useful to know not just what you finally use, but what you
rejected on the way. There are so many good driver tubes out there - 6072,
7062, 7119 etc. etc.
Andy Evans: andy@artsandmedia.com
Visit our website: http://www.artsandmedia.com
- ----- Original Message -----
From: Jim Dudley <jimd@polaris.net>
To: Allen Wright <AllenVSE@compuserve.com>; AAJoeNet <sound@lists.io.com>
Sent: Thursday, December 28, 2000 4:54 PM
Subject: Re: [JN] 5687 vs 5842
> Thanks folks for the input! I was looking for some opinions on how their
> sound differs but I got some good advice anyway. You guys know how to
> sniff out lazy! Based on great success with JL's 5687 linestage and SB's
> input I plan to start with Steve's coupled 5687 driver design. I'm
already
> familar with the 5842 in this position. Hope to offer more later.
>
> Jim Dudley
>
> -----Original Message-----
> From: Allen Wright <AllenVSE@compuserve.com>
> To: AAJoeNet <sound@lists.io.com>
> Date: Thursday, December 28, 2000 5:59 AM
> Subject: [JN] 5687 vs 5842
>
>
> >Jim asked:
> >
> >>>>Opinions wanted: How do the above 2 tubes differ in sound flavor...My
> >breadboarded amps are impatiently waiting for a new driver.......<<<
> >
> >Jim, why not try both yourself, and report back? With the experimenters
> >luxury of a breadboard setup, you are in the prime position to test this
> >out - quickly and relatively easily - and then you will have first hand
> >knowledge for yourself in _your_ system.
> >
> >Your opinion is more than valid and I'm sure we would all be interested
in
> >what you experience.
> >
> >I say "Go for it!"
> >
> >Allen (VSE)
> >
> >
> >
>
=========================================================================
From: "Steve Berger" <aprilsound@earthlink.net>
Subject: Re: [JN] 5687 vs 5842
Date: Fri, 29 Dec 2000 00:09:32 -0500
Source: Sound Digest Archive v02.n771
AMEN!!
Steve
- -----Original Message-----
>I know there are many on this list who believe otherwise, but IME a 5842
>simply can't drive a 300B to full output, unless of course it's running
>off a 250V supply, but then you'd be using a 2A3, right? Even then, it's
>marginal at best. I highly value dynamic headroom in my driver stage,
>and the 5842 just doesn't have it. IIRC, though, Slagle has had some
>success with grid chokes so the onset of that dreaded grid current is
>delayed, providing more output swing.
>
>IMO, the 5842 makes a great battery-biased transformer-coupled line
>stage if you need a lot of gain.
>
>JL
>
=========================================================================
From: j45yip@netscape.net (Johari Yip)
Subject: [JN] 5687WB
Date: Sat, 28 Jul 2001 11:27:08 -0400
Source: Sound Digest Archive v02.n935
Hi everyone,
Anyone knows what's the difference, if there's any, between a 'standard' 5687 and one with the 'WB'
letters behind? Appreciate any information. Thanks in advance.
- --
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: "Paul De Raymond Leclercq" <Pderl@btinternet.com>
Subject: Re: [JN] 5687WB
Date: Sat, 28 Jul 2001 19:18:23 -0700
Source: Sound Digest Archive v02.n935
The "W" suffix means rugged - i.e tested to resist a degree of shock etc.,
not necessarily a good thing for audio since the heftier structure can
increase leakage currents. Fine for a jeep on the battlefield, but not
quite the thing for your living-room. Many folk imagine thqt ruggedness =
low microphony. This is nonsense as my own experiments have demonstrated
The suffixes "A" and "B" usually relate to controlled heater warm-up time -
essential for series strings. Since 5687 was used as a computer valve and
they used thousands, series heaters were probably utlilised.
Paul Leclercq
- ----- Original Message -----
From: Johari Yip <j45yip@netscape.net>
To: <sound@deliverator.io.com>
Sent: Saturday, July 28, 2001 8:27 AM
Subject: [JN] 5687WB
> Hi everyone,
>
> Anyone knows what's the difference, if there's any, between a 'standard'
5687 and one with the 'WB' letters behind? Appreciate any information.
Thanks in advance.
> --
> Johari Yip
> ===================
> j45yip@netscape.net
> ===================
>
>
>
> __________________________________________________________________
> Your favorite stores, helpful shopping tools and great gift ideas.
Experience the convenience of buying online with Shop@Netscape!
http://shopnow.netscape.com/
>
> Get your own FREE, personal Netscape Mail account today at
http://webmail.netscape.com/
>
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] 5.6mH FILTER or Fil choke -- was SHOCKING CHOKE COOKING
Date: Thu, 20 Jan 2000 20:21:30 EST
Source: Sound Digest Archive v02.n411
In a message dated 1/20/00 1:42:45 PM US Mountain Standard Time,
rfrancis@glasscity.net writes:
> What struck ME was this use of a 5.6 MILLI-henry choke as a filter choke.
Greets Jeets Neets,
Last year added a 6.25 mH air core Xover choke right off the rectifier. It
seemed to help low level resolution on the circuit du jour. It stayed in
circuit for several months, tens of circuits. When I did a cleanup, removing
it did not seem to change anything, so I left it out.
Some of these little tunings are very circuit specific.
I may never define the sonic general theory of relativity :)
Happy Ears!
Al B^}
=========================================================================
From: Rick Francis <rfrancis@glasscity.net>
Subject: [JN] 5.6mH FILTER or Fil choke -- was SHOCKING CHOKE COOKING
Date: Wed, 20 Jan 1999 14:48:59 -0500
Source: Sound Digest Archive v02.n411
Dave Slagle wrote:
>
> >I wonder what adding that 50 ohms does to the first cap... i guess it
> >limits the AC charging current i would think it would reduce the overall
> >filtering, and would respond differently under static and dynamic
> >conditions... i guess i would think it would make the filter behave more
> >choke like... i guess i will try cap input with a 50 ohmer in series at
> >some point today... and see what happens.
What struck ME was this use of a 5.6 MILLI-henry choke as a filter
choke. Will this work for 120ma??? Is there a formula for minimum
inductance to still work as a CLC instead of the two C's looking like
one cap?
If even half a henry is 100 times more than necessary, I guess I could
try FILAMENT chokes. I've got one that's .005H (5 millihenries), and
only 0.03 ohms! Good for 8 amps, as I recall.
Rick
>
=========================================================================
From: Thomas Danley <Tom@ppci.com>
Subject: [JN] 5702, 5703, 5784 ?
Date: Fri, 15 Jun 2001 20:59:16 -0500
Source: Sound Digest Archive v02.n911
Hi all
After looking at the exotic tubes some of you are trying, more over being
impressed at the amount of information you have gathered, I figured you all
are my best chance to figure out what a couple tubes I have are.
Given where they are from I figure they might be "exotic" as well but I have
no data on any of them.
They are what was called pencil tube (I think), have a flat ceramic socket and
are mounted, shielded and heat sunk with a springy, perforated copper clip
which encircles the entire body of the tube and is riveted to the chassis with
tiny rivets.
Any info is appreciated
Tom Danley
=========================================================================
From: Ken Gilbert <ride5000@ride.ri.net>
Subject: [JN] 572-30 amp
Date: Tue, 30 May 2000 19:55:16 -0400
Source: Sound Digest Archive v02.n560
well, since last i posted about this project, i have collected some parts:
principally, two very nice magnequest "peerless" center tapped chokes, 200H per
side, 20mA.
in the last discussion, various methods to drive the 572's were discussed. i
had considered the plitron donuts for opts, which kurt said he may have some
first-hand experience with shortly. i have pretty much settled on a pp
topology, with the purchase of the two ct chokes. i'm looking at something
around 900V of B+ for the 572's. power output should be quite considerable.
now, how to best use the chokes in the driver stage?
one idea would be to use cathode followers, directly coupled to the output
grids. the chokes could be used as loads for the cathodes, with the additional
benefit of the "enforced" balance in voltage. this also prevents the 572 grid
current from passing through the choke, since the current would be sourced from
the cathodes themselves.
the other option would be plate loaded drivers. i know many on this list abhor
the sound of cf's, and the 572's could probably be driven by a low rp triode's
plate. the downside here, as i see it, is that the 572 grid current must pass
through the choke, obviously limiting the max ig to 20 mA. that's kind of low
for these bad boys--i am looking at something like 60 mA or so at max swing.
which brings me to the question at hand--essentially, how is the current limit
of the choke determined? is it purely a matter of flux, or is it
copper-related, or perhaps both?
in order to insure that the plates of the drivers had the balls to pull those
grids high, i'd have to make the standing ip of the drivers equal to the max
expected ig, or 60mA. that's a factor of three over the current limit. i feel
that's too much.
otoh, the cf driver route, with chokes in the cathode circuit, does not suffer
from the same limitations... if the 572 grids start sucking up electrons,
they're going to simultaneously appear at the driver cathodes, which are held
"high" quite well by the action of the cf. essentially, i could get by with a
standing driver current of 20mA per side with no problem.
as i see it, cathodes are great for sourcing current, and plates are good for
sinking it. so naturally, for sourcing grid current, the cathode is the way to
go. but what will my ears think? will they never forgive my choices?
what does the collective mind of the joelist think?
ken gilbert
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] 572-30 amp
Date: Wed, 31 May 2000 00:27:12 EDT
Source: Sound Digest Archive v02.n560
In a message dated 5/30/00 5:51:04 PM US Mountain Standard Time,
ride5000@ride.ri.net writes:
> what does the collective mind of the joelist think?
>
> ken gilbert
>
Greets Jeets Neets,
Well, the compacted mind of me is being joyously enchanted by an SV83 with a
plate choke load parafeed driving a 1:1 IT to a 2a3 grid.
OPT is simple SE, one-electrom ubt-3.
opt bias is radical 750 ohm bias resistor bypassed by 66 uF . Right out of
the RCA rcvng tube book.
Wow!
Even music is fun to listen to on this amp!
Happy Ears!
Al B^}
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] 572-30 amp
Date: Wed, 31 May 2000 10:41:17 -0400
Source: Sound Digest Archive v02.n560
hi ken,
see comments below:
> ----------
> From: Ken Gilbert[SMTP:ride5000@ride.ri.net]
> Sent: Tuesday, May 30, 2000 7:55 PM
> To: sound@lists.io.com
> Subject: [JN] 572-30 amp
>
> well, since last i posted about this project, i have collected some parts:
> principally, two very nice magnequest "peerless" center tapped chokes,
> 200H per
> side, 20mA.
>
wow. that's a lot of henries!
are you sure it's not 200H total and 50H per side?
no matter, 50H should be fine for any reasonable driver in this situation...
> in the last discussion, various methods to drive the 572's were discussed.
> i
> had considered the plitron donuts for opts, which kurt said he may have
> some
> first-hand experience with shortly. i have pretty much settled on a pp
> topology, with the purchase of the two ct chokes. i'm looking at
> something
> around 900V of B+ for the 572's. power output should be quite
> considerable.
>
looks like about 100W into 10K load swinging from -30 to +70V.
that's about as far as i would push the grid for this application.
grid current is taking off at higher grid voltage at low
plate voltages...
a 5K load will allow you to push the grid up to +80 or more
with still reasonable grid impedance. net result 110W at +80.
maybe 125W if you really push...
biasing is more interesting subject, though...
> now, how to best use the chokes in the driver stage?
>
> one idea would be to use cathode followers, directly coupled to the output
> grids.
>
i like this choice. especially with a choke load.
back to biasing...
with a 900V supply, you're going to have to have some negative bias, or at
least zero bias to keep the plate dissipation below the 125W limit.
this will require a negative supply for the CF.
this is a bummer because a huge benefit of the choke load is the flyback
effect that allows you to reduce the supply voltage.
in this case, it would be nice to simply ground the choke center-tap.
obviously, the DCR of the choke will develop some static
positive grid bias.
if this could be kept > +10V then perhaps a supply of 800V would work.
> the chokes could be used as loads for the cathodes, with the additional
> benefit of the "enforced" balance in voltage.
>
yes, so long as the DCR of the choke is symmetrical
and the tubes are well matched.
> this also prevents the 572 grid
> current from passing through the choke, since the current would be sourced
> from
> the cathodes themselves.
>
yes, with a static positive bias, some of the cathode current would go
straight into the grid...
the choke is in parallel.
> the other option would be plate loaded drivers. i know many on this list
> abhor
> the sound of cf's,
>
i'm not one of the many ;)
> and the 572's could probably be driven by a low rp triode's
> plate. the downside here, as i see it, is that the 572 grid current must
> pass
> through the choke, obviously limiting the max ig to 20 mA.
>
only if you DC couple the driver plate to the output grid.
> that's kind of low
> for these bad boys--i am looking at something like 60 mA or so at max
> swing.
>
the 60mA peak is not so much the problem. this is an AC peak.
however, because of the modulation of grid impedance with signal
the current waveform will be assymetrical. this distortion will cause a dc
average current to add to the static DC flux
which will eat into your flux margins.
> which brings me to the question at hand--essentially, how is the current
> limit
> of the choke determined? is it purely a matter of flux, or is it
> copper-related, or perhaps both?
>
in an audio choke the copper effects are probably orders of magnitude below
the core effects.
> in order to insure that the plates of the drivers had the balls to pull
> those
> grids high, i'd have to make the standing ip of the drivers equal to the
> max
> expected ig, or 60mA.
>
i think this is a common misconception.
it is not necessarily so. it's just that you would like
the driver stage to be least affected by loading and drive level.
in this type of amp (positive grid current) it is practically
unavoidable. but this is not necessarily a BAD thing.
to some extent, the compression in the grid circuit compensates for
compression in the plate.
also, shifting of the bias based upon signal dynamics
although often overlooked, does seem to have some benefits
(at least it works in the right direction - to counter overload).
i have not played with Class A2 in push-pull, but many of the text-book
benefits of Push-Pull are inherent in SE class A2.
PP may be further improvement, or a complete waste of a tube ;)
> that's a factor of three over the current limit. i feel
> that's too much.
>
again, as long as the tube can supply the peak, and the distortion is low,
the choke only needs to pull 1/2 of the peak dc-wise.
in this case, all bets are off...
> otoh, the cf driver route, with chokes in the cathode circuit, does not
> suffer
> from the same limitations... if the 572 grids start sucking up electrons,
> they're going to simultaneously appear at the driver cathodes, which are
> held
> "high" quite well by the action of the cf. essentially, i could get by
> with a
> standing driver current of 20mA per side with no problem.
>
well the CF will pull the grid high, but the stored energy in the choke will
release like a spring and pull (push?) the grids "low",
too. in this case you're giving the choke the "easy job".
> as i see it, cathodes are great for sourcing current, and plates are good
> for
> sinking it. so naturally, for sourcing grid current, the cathode is the
> way to
> go.
>
mmmm...
> but what will my ears think? will they never forgive my choices?
>
they are YOUR ears. i (or any other joe) cannot answer this for you.
the CF approach is much easier to implement (especially allowing
some DCR positive bias on the 572 grids).
plate loading will require some funky DC coupling scheme
(stacked supply seems easiest).
> what does the collective mind of the joelist think?
>
no such thing... ;)
beside, who are you building the amp for, anyway?
have fun!
bob.d.
=========================================================================
From: An-Shyang Chu <achu@medcaminc.com>
Subject: Re: [JN] 572-30 amp
Date: Wed, 31 May 2000 08:39:17 -0700
Source: Sound Digest Archive v02.n561
Hi Ken,
Ken Gilbert wrote:
>
> well, since last i posted about this project, i have collected some parts:
> principally, two very nice magnequest "peerless" center tapped chokes, 200H per
> side, 20mA.
>
Is this the 17173(?) that was on e-bay a while back? I have the same
choke and from what I remember it is not a 200H per side at 20 mA.....
maybe half of that?? Paul Joppa did a quick study a while on this
choke, Paul or Dave??
hopper
=========================================================================
From: "Daniel J. Marshall" <danmarshall@worldnet.att.net>
Subject: Re: [JN] 572-30 Amp
Date: Wed, 31 May 2000 10:57:07 -0700
Source: Sound Digest Archive v02.n561
> Hi Ken,
>
> Ken Gilbert wrote:
> >
> > well, since last i posted about this project, i have collected some parts:
> > principally, two very nice magnequest "peerless" center tapped chokes, 200H
> per
> > side, 20mA.
> >
>
> Is this the 17173(?) that was on e-bay a while back? I have the same
> choke and from what I remember it is not a 200H per side at 20 mA.....
> maybe half of that?? Paul Joppa did a quick study a while on this
> choke, Paul or Dave??
>
> hopper
Hi All,
I saw these listed on eBay (if indeed they are the same) and noted that
they are a split-bobbin design. I presume one-half of the winding is on
either side of the bobbin. If this is the case I would not expect the
coupling between the two sides to be very good. This would require the
driving circuit to be well balanced and would preclude relying on the
choke to add much to the balancing of the signal.
As I previously reported here, I recently bought a pair of ITs from the
same eBay source. They were mfg by Magnequest based upon the Peerless
G324A design. I found them to have absolutely wretched performance,
starting to depart from flat-response/equal-phase at around 2.5 kHz with
massive ringing within the audio band when driven by their primary
characteristic impedance (generator through series resistor). I have
never seen an audio component perform as poorly. I will go back and
determine whether the secondaries can be loaded to improve their
performance. This perhaps would result in some improvement, but the
amplitude-response/phase-tracking of the two sides of the secondary was
so unbelievably bad I doubt they could be tamed for anything other than
use in a bass amp, or midrange at best.
So, I think some serious bench testing would be in order for the chokes
before launching headlong into incorporating them in an amplifier
design, assuming them to be quality devices, based upon the reputation
of Peerless and/or Magnequest. However, ct chokes do tend to be more
well-mannered than do ITs, so this might not be an issue, but I would do
some test to make sure. You need to drive them with a square wave
through a variable impedance and see what kind of damping htey require.
It would seem that they would be a bit wimpy to drive 572-30 tubes. I
would think that a good PP 6BQ5 amp would make a suitable driver for the
572-30s, perhaps using a negative supply with opt ct at ground
potential, or thereabouts, depending on the plate voltage of the 572s.
Triodes, or triode-strapped pentodes of your choice for driver tubes
would give you a relatively low drive impedance, or better yet, use the
screen taps to drive the grids. The classic method used to drive such
an tubes is to use step-down driver transformers. This would be a cheap
way to achieve the same thing, assuming you have some suitable
transformers or amps lying about.
I have played with SV811-10 a little (in SE), at least enough to learn
that a fairly low-impedance driver is essential to prevent compression
of the drive signal on the plus swing. It was pointed out by Bob D that
some compression could be used to offset the non-linearity of the tube.
This might be the case and may be well understood by those who have
designed such amplifiers, but before making this assumption I would
drive a pair of tubes in a bench test using a low impedance source with
variable resistors in series with the grids and note the effect on the
odd order distortion components vs driver resistance. If lower odd
order distortion products can be dialed in by varying the source
sesistance, then this would obviously be the way to go, i.e., design the
driver for a specific impedance. Anyway, this is mostly speculation,
as I have not spent much time messing with hi-mu transmitting triodes.
I do have a project on the back burner though and will finesse it and
report the results later.
Somehow, using the choke in the cathodes of a CF driver circuit does not
grab me as being a good approach. If you have CFs then you have fairly
low impoedance so why use the chokes there. It woulds seem that the ct
choke would be better used as grid or plate chokes preceeding the CFs.
Dan Marshall
=========================================================================
From: TubeGarden@aol.com
Subject: Re: [JN] 572-30 Amp
Date: Wed, 31 May 2000 17:01:32 EDT
Source: Sound Digest Archive v02.n561
In a message dated 5/31/00 11:04:36 AM US Mountain Standard Time,
danmarshall@worldnet.att.net writes:
> wretched performance
Hi Ears!
My Ekectra-Print 3634 1:1 are being driven by triode wired SV83 parafeed to
drive my 2A3. OPT is UBT-3.
Best sound ever, again.
I like this hobby. Lots of positive reinforcement.
Happy Ears!
Al B^}
=========================================================================
From: Ken Gilbert <ride5000@ride.ri.net>
Subject: Re: [JN] 572-30 amp
Date: Wed, 31 May 2000 18:58:12 -0400
Source: Sound Digest Archive v02.n561
>> well, since last i posted about this project, i have collected some parts:
>> principally, two very nice magnequest "peerless" center tapped chokes, 200H
per
>> side, 20mA.
>>
>
>Is this the 17173(?) that was on e-bay a while back? I have the same
>choke and from what I remember it is not a 200H per side at 20 mA.....
>maybe half of that?? Paul Joppa did a quick study a while on this
>choke, Paul or Dave??
exactly, hopper--i got it for a mega steal... 40 bucks for a PAIR of them!! i
almost shit my pants, expecting to be rapidly lost in the deluge of bidding
right around the closing time, but i was NOT. my first bid, the only bid,
stayed at 40. 5 bucks shipping from NJ to RI makes me a happy man. the
seller, i assume, is not quite as happy.
every once in a while, e-bay amazingly comes through.
what bob d said makes more sense--it's most likely 200h across the whole
winding, making it 50 per half. 200 seemed kind of ludicrous to me, but then
again mike is a good winder. ;-)
ken gilbert
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] 5755?
Date: Fri, 05 Nov 1999 13:42:19 -0500
Source: Sound Digest Archive v02.n322
this isn't a great deal.
angela has them for less.
and he has loads of them.
i bought a dozen about 4 years ago for $10.
in fact, steve was giving them away to anyone who could
come up with a good use for them.
never heard of anyone taking him up on the offer...
unfortunately,the 5755 is not really a 6sl7 equivalent.
the only thing it has in common is the mu = 70.
the gm is *way* lower...
in the 400-500 uS range.
these were apparently used as dc differential amplifiers
in industrial/instrument applications.
the typical application ran them at fractional mA plate currents
with high (1 meg) loads.
the one thing going for them was well matched triodes in one bottle. not
sure this was necessarily a challenge given the low
gm....
anyway, i have used them in a few circuits.
still have one in a guitar amp, but it has to go.
the main problem is the noise.
i guess this should have been expected from a lo gm tube.
if you want to experiment, i suggest you grab a few from steve
before you get stuck with a bunch of tubes you'll never use...
then again, 37.50 for a local source might be cheaper
than shipping form the US.
you can always decorate the christmas tree with them....
have fun!
bob.d.
> ----------
> From: Christian Rintelen[SMTP:rintelen@datacomm.ch]
> Reply To: rintelen@datacomm.ch
> Sent: Friday, November 05, 1999 12:17 PM
> To: Joelist
> Subject: [JN] 5755?
>
> Joes,
>
> what do you think about this tube? I was offered them NOS @ $ 37.50 for
> 10 pieces. I guess it's like a 6SL7 in 9-pin-miniature. Any experiences?
>
> Thanks for your advice!
>
> Christian
>
=========================================================================
From: Christian Rintelen <rintelen@datacomm.ch>
Subject: [JN] 5755?
Date: Fri, 05 Nov 1999 18:17:27 +0100
Source: Sound Digest Archive v02.n322
Joes,
what do you think about this tube? I was offered them NOS @ $ 37.50 for
10 pieces. I guess it's like a 6SL7 in 9-pin-miniature. Any experiences?
Thanks for your advice!
Christian
=========================================================================
From: Grover Gardner <groverg@postoffice.att.net>
Subject: Re: [JN] 5755?
Date: Fri, 5 Nov 1999 13:51:41 -0500
Source: Sound Digest Archive v02.n323
At 6:17 PM +0100 11/5/99, Christian Rintelen wrote:
>Joes,
>
>what do you think about this tube? I was offered them NOS @ $ 37.50 for
>10 pieces. I guess it's like a 6SL7 in 9-pin-miniature. Any experiences?
>
>Thanks for your advice!
Yes, Very nice little tubes. Neat box-like plate structure, warmer
and fuller than a 5751, different pinout, works just like a 6SL7.
I'd like to do a phono stage with these...
- -------
Grover Gardner
groverg@postoffice.att.net
=========================================================================
From: Christian Rintelen <rintelen@datacomm.ch>
Subject: Re: [JN] 5755?
Date: Sat, 06 Nov 1999 15:39:42 +0100
Source: Sound Digest Archive v02.n323
Joes,
thanks for your advice. It was a mixed bag, though. Gordon Rankin said it
was a great tube and advised to buy it, whereas Bob Danielak said, the 5755
makes a nice christmas tree decoration...
Christian
=========================================================================
From: "Danielak, Robert M" <robert.m.danielak@lmco.com>
Subject: RE: [JN] 5755?
Date: Wed, 10 Nov 1999 12:32:54 -0500
Source: Sound Digest Archive v02.n328
well, who would you listen to.....? ;)
actually, i only said that the price was not great
and in my experience these tubes can be noisy.
i encourage you to experiment and see how they work for you.
there are plenty of better tubes to use as xmas lights.... ;)
i'm thinking of an 833 on the top of my tree this year!
happy holidays!
bob.d.
> ----------
> From: Christian Rintelen[SMTP:rintelen@datacomm.ch]
> Reply To: rintelen@datacomm.ch
> Sent: Saturday, November 06, 1999 9:39 AM
> To: Joelist
> Subject: Re: [JN] 5755?
>
> Joes,
>
> thanks for your advice. It was a mixed bag, though. Gordon Rankin said it
> was a great tube and advised to buy it, whereas Bob Danielak said, the
> 5755
> makes a nice christmas tree decoration...
>
> Christian
>
=========================================================================
From: Christian Rintelen <rintelen@datacomm.ch>
Subject: Re: [JN] 5755?
Date: Wed, 10 Nov 1999 20:18:55 +0100
Source: Sound Digest Archive v02.n328
I actually didn't plan to buy a christmas tree this year ;-)
Christian
"Danielak, Robert M" wrote:
> well, who would you listen to.....? ;)
>
> actually, i only said that the price was not great
>
> and in my experience these tubes can be noisy.
>
> i encourage you to experiment and see how they work for you.
>
> there are plenty of better tubes to use as xmas lights.... ;)
>
> i'm thinking of an 833 on the top of my tree this year!
>
> happy holidays!
>
> bob.d.
>
> > ----------
> > From: Christian Rintelen[SMTP:rintelen@datacomm.ch]
> > Reply To: rintelen@datacomm.ch
> > Sent: Saturday, November 06, 1999 9:39 AM
> > To: Joelist
> > Subject: Re: [JN] 5755?
> >
> > Joes,
> >
> > thanks for your advice. It was a mixed bag, though. Gordon Rankin said it
> > was a great tube and advised to buy it, whereas Bob Danielak said, the
> > 5755
> > makes a nice christmas tree decoration...
> >
> > Christian
> >
=========================================================================
From: "Harry Pitaro" <pitaro@ozemail.com.au>
Subject: [JN] 5842 dc 45 amp update
Date: Wed, 2 Jun 1999 14:08:35 +1000
Source: Sound Digest Archive v02.n162
Hi all,
Just thought I'd share my joy with you guys.
A couple of weeks ago I finished assembling a 3 bread board version of the
45 amp I've been working on. The power supply chassis (which is almost
impossible for one person to lift), consists of 4 separate 1% regulated
power transformers and choke input filter stages, i.e., a separate power
supply for each tube. The 5842 uses a GZ34 rectified supply and the 45 uses
an 83 rectified power supply. The 5842 is plate choke loaded, lead acid
battery cathode biased running at 140V 13mA and the 45 is cathode biased
running at about 220V 36mA. The only capacitor in the whole signal path,
other than power supply caps, is the 45 cathode bypass caps which are about
100uF.
I then ran an 11 wire umbilical cord to each of the two signal chassis
supplying AC heaters, HT, centre taps and earth. I used two switches for
turn on, one for mains which turns on all the heaters, the other between the
HT centre taps and ground for B+ supply. I was initially concerned about
induced hum from the AC heater wires in the umbilical but this doesn't seem
to have been an issue. I star grounded everything on the signal chassis and
then ran a single wire back to the power supply chassis for earthing.
WARNING - Subjective comments follow
I was pretty pleased with the sound of the amp so I took it over to a couple
of friends. The amp sounded different in each of their systems but in both
cases the amp excelled. It has an amazing level of detail without being
bright. The emotion in the music is portrayed very very well. It also has
exceptional transients and tight bass. It is very neutral, transparent and
sounds totally unstressed. I have not been able to make it clip.
If I had one very tiny issue, it would be to try and make the amp a little
"fruitier" for want of a better descriptor. I think the 5842 can be a little
clinical sounding so I might try a different driver tube. It could also be
the fact that my speakers roll off very quickly after 50Hz. I could try to
either of the tubes with a little more current, say 20mA for the 5842 and
45mA for the 45. Suggestions?
Harry Pitaro
pitaro@ozemail.com.au
Melbourne, Australia
=========================================================================
From: "Kurt Th. Steffensen" <kurt-steffensen@teliamail.dk>
Subject: Sv: [JN] 5842 dc 45 amp update
Date: Wed, 2 Jun 1999 14:30:36 +0300
Source: Sound Digest Archive v02.n163
>Hi all,
>
>Just thought I'd share my joy with you guys.
>
Good Harry.
Let´s go back to the real world.
>A couple of weeks ago I finished assembling a 3 bread board version of the
>45 amp I've been working on.
These 45´s is some of the best triodes possible.
The power supply chassis (which is almost
>impossible for one person to lift), consists of 4 separate 1% regulated
>power transformers and choke input filter stages, i.e., a separate power
>supply for each tube.
That sound fine to me. - I wonder what that reulated power transformer is though ?
The 5842 uses a GZ34 rectified supply and the 45 uses
>an 83 rectified power supply. The 5842 is plate choke loaded, lead acid
>battery cathode biased running at 140V 13mA and the 45 is cathode biased
>running at about 220V 36mA. The only capacitor in the whole signal path,
>other than power supply caps, is the 45 cathode bypass caps which are about
>100uF.
>
Good rectifiers. I can not remember if I have ever played with the 5842.
What is the Eupean