2a3 Triode Guitar Amplifier

2a3geek · 23rd November 2008, 03:08 PM

I saw a posting over the in the 'tubes' forum several months ago regarding 2a3 tubes used in amps. It got me interested in who is using the old Triodes for guitar amps and trying to figure out the best approach for making one.
I have found one company (Straub Amps who is making one. Their clips sound excellent, I think they are onto something with the thick sound they are getting.YouTube Clips I am interested in going down this road on an amp for myself, but I can't find much information on them. I did contact them, they were very nice, but would not provide the schematic for the amp.
Has anyone had a chance to play one, look a the circuit? I am interested in the voltages he is running, the bias circuit and circuit for the driver tube.
I really believe these make great low wattage amps, full and thick. Any suggestions?

Fuling · 23rd November 2008, 03:21 PM

Might work well for home use (although I think triodes sounds dull in guitar apps) but direct heated tubes are probably too fragile (and possibly microphonic) for stage use.
I guess the standard OP with 250V plate-cathode, 60mA, 2,5k load and -45V on the grid would be a good start giving about 3,5W out.

2a3geek · 23rd November 2008, 07:34 PM

Thanks!
He claims to be getting 12w class A push pull.....he told me that he uses the JJ 2a3's because they have 40w Pamax and he can get 12w in true class A. So, I assume he is pushing them harder than 250/60ma.
The clips sure don't sound dull, but I am sure it has a lot of bottom end. I am assuming that I will need to modify the tone stack to get more highs and roll off lower freq.
Anyone built a 2a3 guitar amp?

23rd November 2008, 03:08 PM	#1
2a3geek diyAudio Member Join Date: Nov 2008	2a3 Triode Guitar Amplifier I saw a posting over the in the 'tubes' forum several months ago regarding 2a3 tubes used in amps. It got me interested in who is using the old Triodes for guitar amps and trying to figure out the best approach for making one. I have found one company (Straub Amps who is making one. Their clips sound excellent, I think they are onto something with the thick sound they are getting.YouTube Clips I am interested in going down this road on an amp for myself, but I can't find much information on them. I did contact them, they were very nice, but would not provide the schematic for the amp. Has anyone had a chance to play one, look a the circuit? I am interested in the voltages he is running, the bias circuit and circuit for the driver tube. I really believe these make great low wattage amps, full and thick. Any suggestions?

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23rd November 2008, 03:21 PM	#2
Fuling diyAudio Member Join Date: Aug 2001 Location: Sweden (Mora)	Might work well for home use (although I think triodes sounds dull in guitar apps) but direct heated tubes are probably too fragile (and possibly microphonic) for stage use. I guess the standard OP with 250V plate-cathode, 60mA, 2,5k load and -45V on the grid would be a good start giving about 3,5W out.

23rd November 2008, 07:34 PM	#3
2a3geek diyAudio Member Join Date: Nov 2008	Thanks! He claims to be getting 12w class A push pull.....he told me that he uses the JJ 2a3's because they have 40w Pamax and he can get 12w in true class A. So, I assume he is pushing them harder than 250/60ma. The clips sure don't sound dull, but I am sure it has a lot of bottom end. I am assuming that I will need to modify the tone stack to get more highs and roll off lower freq. Anyone built a 2a3 guitar amp?

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