Recent Posts

61

Tube Amp Building - Tweaks - Repairs / Re: Anyone care to help me finish my build ?

« Last post by antolc37 on July 21, 2026, 01:31:26 am »

The presence potentiometer reduces the hiss indeed so maybe I could add some more NFB (I've already tried disconnecting it completely), I will try adding a stereo potentiometer after the PI if it doesn't do the trick. You're probably right, I remember that when the power tube was biased cooler (I had only 630R at my disposal) I didn't have the squeal.

62

Tube Amp Building - Tweaks - Repairs / Re: Deville Transformers Reuse

« Last post by sluckey on July 20, 2026, 09:23:40 pm »

Transformers will be fine for a 6L6 AB763. But the PT is designed for a FWB rectifier so you should just use the Deville HT power supply. Forget about a tube rectifier.

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Tube Amp Building - Tweaks - Repairs / Re: Princeton Reverb circuit refinements

« Last post by Carlsoti on July 20, 2026, 09:12:40 pm »

You're unlikely to get the deep drip of an old Gibbs pan with a new one from any manufacturer. That's just the way things are. I don't futz with old broken reverb pans anymore. The juice is not worth the squeeze.

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Tube Amp Building - Tweaks - Repairs / Deville Transformers Reuse

« Last post by king_me on July 20, 2026, 08:34:31 pm »

Hello !!!

 New to the forum and ive been searching high and low but maybe someone here can help me. Looking to build a Hoffman AB763 One Channel or Bassman 6g6b circuit  out of a fender deville chassis that has a damaged tube board. Not looking to save the circuit board but would like to save the transformers, chassis and 410 cab. Jus need to know if the transformers are good for either of the builds. Thanks for reading this and hope some can answer this or point me in the right direction.

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Tube Amp Building - Tweaks - Repairs / Re: Anyone care to help me finish my build ?

« Last post by AlNewman on July 20, 2026, 05:16:04 pm »

Maybe you need to adjust the voltage divider after the PI?
Maybe you need to adjust the ratio of the NFB circuit?

You might just be hitting the power tubes too hard.

What happens if you lift the NFB?  Maybe it's as simple as reversing the OT primaries.

66

Tube Amp Building - Tweaks - Repairs / Re: Anyone care to help me finish my build ?

« Last post by antolc37 on July 20, 2026, 04:15:47 pm »

oh ok that's good to know, I had hoped this was the origin of the hiss though and not the lead dress or something wrong with the layout

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Tube Amp Building - Tweaks - Repairs / Re: Anyone care to help me finish my build ?

« Last post by sluckey on July 20, 2026, 03:41:11 pm »

That tone stack is drawn weirdly but if you rotate the bass and mid pots and line them up under the treble pot you will see a very familiar TMB stack.

Those 22K grid stoppers should not be a problem.

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Tube Amp Building - Tweaks - Repairs / Re: Anyone care to help me finish my build ?

« Last post by antolc37 on July 20, 2026, 03:16:36 pm »

sure here it is, the exercise was interesting I had to trace it back from the actual circuit which showed me two odd things :
- Tone stack is weird
- 22k grid resistor for V4 is too big I don't rember why I put so much

69

Tube Amp Building - Tweaks - Repairs / Re: Princeton Reverb circuit refinements

« Last post by johnfromcyrene on July 20, 2026, 01:34:45 pm »

i have a new accutronics tank that i heard are not that good anymore.

What do you mean not good, how so?

they say you get a weak reverb from it. they use a press on wire for the transducer i guess. not sure why but thats what i hear.

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Tube Amp Building - Tweaks - Repairs / Re: Anyone care to help me finish my build ?

« Last post by Lectroid on July 20, 2026, 12:49:48 pm »

Schematic?