2 stage IT coupled SE suggestions.?

JandG · 22nd December 2008, 10:18 PM

I am wanting to try something differant than my IT coupled 12bh7/6l6g SE amp. I like fixed bias on outputs, but doesn't have to be, I can just convert. I have Hashimoto H-20-7U outputs that have 5k & 7k w/ g2 UL taps for both & O'Netics 1:1 IT's. Any suggestion would be great for me.
J & G

45 · 22nd December 2008, 10:48 PM

Do you want to stick to those tubes or make another use of your trannies?
How does your previous amp "look"?

Cheers,
45

JandG · 22nd December 2008, 10:59 PM

I am wanting to try differant tubes . My previouse amp looked like cra...All test clipped, etc.. & huge , many PS's & just way to crazy & dangerouse ....*s*. This one is going into a chassis I swear......................................... I have a a hammond 193L so choke input supply is o.k., & many,many motor runs. I am very low on 2a3, no spare 300B, & also very low on 45,so they are out. I actually would like to stay away from those 3 if I can help it. I allready have a 45 SET & 300B PP amp & do not want another expesive output tube amp. Maybe differant driver for 6v6 or 6l6G..? Don't know no really I sure would like to stay with a 2 stage...on this amp.
J & G

Jaap · 23rd December 2008, 11:06 AM

I have a 5842 (or D3a or E810F) => IT => 300B amp. I am planning to rebuild this into a pse 807 amp (pentode connection + local feedback). I will use the same OPT (3,5K) and try mosfet regulated screensupply.

You can of course also use 6L6, EL34, KT66, KT88, etc.

Another idea is screendrive a parallel 6AV5 or other sweep tube.

FlaCharlie · 23rd December 2008, 02:43 PM

Hey JANDG - As you know, I'm not a designer and I don't know if it would lend itself to your front end topology but . . . perhaps a 47 (SE pentode). I do know that the 7k primary of your OT is correct. Beyond that ??? Power out is a bit more than a 45. They're available and not too expensive.

http://www.nj7p.org/Tube4.php?tube=47

. . . Charlie

JandG · 24th December 2008, 12:19 AM

Great idea. I might even have some 47, never thopught of trying those. Wonder what would be a good driver in a 2 stage would be..? Any idea's..? Certainly worth a try.
thanks J & G

45 · 24th December 2008, 01:36 AM

47 driver, KT66 output. Both in triode connection.
Plus 6SN7 RC-coupled input.

KT66 at 400V/63mA/-38V.
http://frank.pocnet.net/sheets/126/k/KT66.pdf

The true replicas are Golden Dragon or Valve Art. Nice sound, IMO.

The russians look, work and sound more like smaller KT88's.......

Using 5K instead of 4.5K, you should still get 5.5W.
You could play a little bit with the operative conditions of 47 looking for both good sound and lower THD (harmonic cancellation).

22nd December 2008, 10:18 PM	#1
JandG diyAudio Member Join Date: Jan 2005 Location: Washington State	2 stage IT coupled SE suggestions.? I am wanting to try something differant than my IT coupled 12bh7/6l6g SE amp. I like fixed bias on outputs, but doesn't have to be, I can just convert. I have Hashimoto H-20-7U outputs that have 5k & 7k w/ g2 UL taps for both & O'Netics 1:1 IT's. Any suggestion would be great for me. J & G

23rd December 2008, 02:43 PM	#5
FlaCharlie diyAudio Member Join Date: Feb 2004 Location: Gainesville, FL	How About SEP? Hey JANDG - As you know, I'm not a designer and I don't know if it would lend itself to your front end topology but . . . perhaps a 47 (SE pentode). I do know that the 7k primary of your OT is correct. Beyond that ??? Power out is a bit more than a 45. They're available and not too expensive. http://www.nj7p.org/Tube4.php?tube=47 . . . Charlie

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22nd December 2008, 10:48 PM	#2
45 diyAudio Member Join Date: Dec 2008 Location: United Kingdom	Do you want to stick to those tubes or make another use of your trannies? How does your previous amp "look"? Cheers, 45

22nd December 2008, 10:59 PM	#3
JandG diyAudio Member Join Date: Jan 2005 Location: Washington State	I am wanting to try differant tubes . My previouse amp looked like cra...All test clipped, etc.. & huge , many PS's & just way to crazy & dangerouse ....s. This one is going into a chassis I swear......................................... I have a a hammond 193L so choke input supply is o.k., & many,many motor runs. I am very low on 2a3, no spare 300B, & also very low on 45,so they are out. I actually would like to stay away from those 3 if I can help it. I allready have a 45 SET & 300B PP amp & do not want another expesive output tube amp. Maybe differant driver for 6v6 or 6l6G..? Don't know no really I sure would like to stay with a 2 stage...on this amp. J & G

23rd December 2008, 11:06 AM	#4
Jaap diyAudio Member Join Date: Dec 2002 Location: Netherlands	I have a 5842 (or D3a or E810F) => IT => 300B amp. I am planning to rebuild this into a pse 807 amp (pentode connection + local feedback). I will use the same OPT (3,5K) and try mosfet regulated screensupply. You can of course also use 6L6, EL34, KT66, KT88, etc. Another idea is screendrive a parallel 6AV5 or other sweep tube.

24th December 2008, 12:19 AM	#6
JandG diyAudio Member Join Date: Jan 2005 Location: Washington State	Great idea. I might even have some 47, never thopught of trying those. Wonder what would be a good driver in a 2 stage would be..? Any idea's..? Certainly worth a try. thanks J & G

24th December 2008, 01:36 AM	#7
45 diyAudio Member Join Date: Dec 2008 Location: United Kingdom	47 driver, KT66 output. Both in triode connection. Plus 6SN7 RC-coupled input. KT66 at 400V/63mA/-38V. http://frank.pocnet.net/sheets/126/k/KT66.pdf The true replicas are Golden Dragon or Valve Art. Nice sound, IMO. The russians look, work and sound more like smaller KT88's....... Using 5K instead of 4.5K, you should still get 5.5W. You could play a little bit with the operative conditions of 47 looking for both good sound and lower THD (harmonic cancellation).

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