project suggestion with spare trans

skyraider · 10th April 2005, 08:10 AM

I have extra set of power trans and SE output trans from my darling project.
The output trans is rated 5watts and the pt output is 200v. The trans are custom-made, wax-potted and has very good freq response up to 50k.
I am considering a 2A3 project with these, or maybe exotic tubes. Any suggestions?

p/s- Initially I wanted to build a 300B with these, but I am guessing the rated power is not enough to be used.

audiousername · 10th April 2005, 08:19 AM

Something more exotic of course

What about SE trioded 829B?
http://www.pmillett.com/829b_amplifier.htm

skyraider · 12th April 2005, 05:17 AM

I think I will stick with the fashion... penthode driving 2a3 triode.
Not brave enough for exotics.

Sch3mat1c · 12th April 2005, 04:01 PM

6W6 or two.

12BY7 if you have a bunch (4 or so).

12B4.

I'd say 6V6 but it likes 250-350V.

'Bout 5 6SN7's

6BM8? Kinda low powered though.

New sweep tubes: GV5, GY5, JF6, ... would look neato; needs 12 pin socket though.

Tim

skyraider · 13th April 2005, 01:18 AM

how about c45? good rapport i get..

12b4, 5687 too low gain, unfortunately.
I already have 6Bm8 amp..
6sn7.. good potential.

audiousername · 13th April 2005, 07:26 AM

Quote:

Originally posted by skyraider
12b4, 5687 too low gain, unfortunately.

Too low gain? One usually isn't too worried about the gain of the output stage as long as the drive requirements aren't too severe...

The µ of the 5687 (14, I think) certainly is high enough. Even the 12B4 (µ=6) is good enough.

andyjevans · 14th April 2005, 09:06 AM

There are some nice low power triodes which are quite cheap. You don't state the Primary impedence of the OPT so you could chose between:
12B4 Ra 1
6CK4 Ra 1.2
6AH4 Ra 1.8
6S4A Ra 3.7

As you go up the Ra you may need to use pairs - certainly the case with 6S4A. As stated, multiple 6SN7 or 6J5GT are also ideas - I've heard those in outputs and they are very sweet and clear. 6J5GT are very cheap, and you can use 7N7 instead of 6SN7. 2C22/7193 would be fantastic, and they're not expensive. Of all the above, that would probably give you the best sound, but you'd need a few and some top caps.

10th April 2005, 08:10 AM	#1
skyraider diyAudio Member Join Date: Jan 2004 Location: malaysia	project suggestion with spare trans I have extra set of power trans and SE output trans from my darling project. The output trans is rated 5watts and the pt output is 200v. The trans are custom-made, wax-potted and has very good freq response up to 50k. I am considering a 2A3 project with these, or maybe exotic tubes. Any suggestions? p/s- Initially I wanted to build a 300B with these, but I am guessing the rated power is not enough to be used.

10th April 2005, 08:19 AM	#2
audiousername diyAudio Member Join Date: Jul 2004 Location: Melbourne, Victoria	Something more exotic of course What about SE trioded 829B? http://www.pmillett.com/829b_amplifier.htm __________________ Jason

12th April 2005, 04:01 PM	#4
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	6W6 or two. 12BY7 if you have a bunch (4 or so). 12B4. I'd say 6V6 but it likes 250-350V. 'Bout 5 6SN7's 6BM8? Kinda low powered though. New sweep tubes: GV5, GY5, JF6, ... would look neato; needs 12 pin socket though. Tim __________________ Seven Transistor Labs Projects and Resources

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12th April 2005, 05:17 AM	#3
skyraider diyAudio Member Join Date: Jan 2004 Location: malaysia	I think I will stick with the fashion... penthode driving 2a3 triode. Not brave enough for exotics.

13th April 2005, 01:18 AM	#5
skyraider diyAudio Member Join Date: Jan 2004 Location: malaysia	how about c45? good rapport i get.. 12b4, 5687 too low gain, unfortunately. I already have 6Bm8 amp.. 6sn7.. good potential.

14th April 2005, 09:06 AM	#7
andyjevans diyAudio Member Join Date: Sep 2003 Location: London	There are some nice low power triodes which are quite cheap. You don't state the Primary impedence of the OPT so you could chose between: 12B4 Ra 1 6CK4 Ra 1.2 6AH4 Ra 1.8 6S4A Ra 3.7 As you go up the Ra you may need to use pairs - certainly the case with 6S4A. As stated, multiple 6SN7 or 6J5GT are also ideas - I've heard those in outputs and they are very sweet and clear. 6J5GT are very cheap, and you can use 7N7 instead of 6SN7. 2C22/7193 would be fantastic, and they're not expensive. Of all the above, that would probably give you the best sound, but you'd need a few and some top caps.

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