Magnatone 113 Head Build

[trobbins]

Yes plate pin 1 on V3A, to V3B grid.

Investigating noise/hum/parasitic feedback issues can take time - one way to progress is to try to understand what is an influence, and what isn't, and make single changes and repeat the same checks. Isolating each section, eg by star grounding and using a separate bypass cap, is one path to take. Swapping valves, and grounding grids along the signal path are other actions that can assist in eliminating, or implicating, certain sections of circuitry.

[David Root]

Thanx, I thought so! I'll soldier on for a while, maybe it will work at lower gain with a 12AU7, somehow I doubt that.

[trobbins]

12AU7 won't give enough gain for the phase shift oscillator.

[David Root]

I agree, 3 phase caps needs 29 minimum, so I tried a 6072. Did the trick--no more ticking, less gain than 12AT7, still sounds good. No significant voltage changes.
Verrry slight ticking at max gain w/no signal, virtually inaudible, and completely inaudible for all practical purposes.

"Ze case is solvedd" as Inspector Clouseau said.
Thanx again for your help tr, and to all who responded. This is the first trem circuit I've done and I sure learned a lot.

[RJ Guitars]

David,

Thanks for building this. I made up a bunch of these chassis and then I discovered some flaw in my original intentions. Then these sat around until I decided to just add them as a bonus to some of you master builder guys. You really made this into something very cool... I would not have guessed it to go this way so you're inspiration is greatly appreciated.

Great looking build, thanks for posting it up with all the fine tweaks.

rj