V72A information - setting the trim cap + usuable mods?

I'm working on a V72A for someone at work, and i'm wondering if theres anyone who knows the procedure for setting the trim cap in the feedback loop and if theres any tested modifications out there that are worth doing?

Also could anyone recommend replacement filter caps for it that are Axial and will fit in the space alotted and are of high quality?

thanks for the help!
-bryan

Maybe Ollie at Tab could help with the caps. I know what a pain that is, I have a couple sittin right here. Tight fit.

You increase the feedback resistor that parallels the cap to the point where the amp just breaks into oscillation, then back it off a bit.
The cap is trimmed so that you have least harmonic distortion at the frequency of your choice, most use 1 k hz.

If you figure out how to measure THD without a machine, let me know!

cj

fun!

Don´t worry about the quality of your caps. All available caps nowadays are of higher quality than those used in the 50s when the V72 was designed. If you want that retro-sound buy the worst caps you can find - they will be the best :grin: