Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Raybob on June 07, 2011, 10:42:51 pm

Title: Hoffman AB763 [missing .02 cap?]
Post by: Raybob on June 07, 2011, 10:42:51 pm

On the Fender 6G16 circuit, there's a .02 cap tying the grid to the plate, essentially across pin 1 and pin 2.  The "Hoffman AB763" doesn't have that capacitor.  Is there a reason that cap is omitted?  Would it improve or detract somehow?  I know, try it and see.  Guess I'm wondering if anyone knows the reason before I go experimenting.

Title: Re: Hoffman AB763 [missing .02 cap?]
Post by: sluckey on June 08, 2011, 06:10:10 am

I don't see any tubes with a .02 cap tying grid to plate. However, the tremolo oscillator has a .02 tying plate to cathode. Is this what you're talking about? That cap is essentially connected from plate to ground and would reduce the amplitude of the trem signal and probably improve it's shape too. The cap is not essential. Maybe Doug wanted a little more trem. Only the shadow knows.

Title: Re: Hoffman AB763 [missing .02 cap?]
Post by: EL34 on June 13, 2011, 05:17:23 pm

I can't say anything unless I have a picture of which part it is and where it is in one of my layout diagrams.

You can take my layout diagrams and cut-copy-paste-crop them here.