I'd have to say I agree about replacing electrolytic caps. Maybe I'll practice soldering on boards, but for now I don't feel competent. My Tech was being a little facetious with the 80 year thing. I'm of retirement age and he's a little older so he was alluding to components outliving their owners. I didn't make that clear.
The amp is a little tricky to adjust/fix. The input board has a pot for each channel, but figuring out what to balance is a little confusing. I sat down with a pin out of the tubes and remembered what Dan explained. It might not make sense to most techs/designers (don't know), but it works.
That was originally my tweeter amp for a pair of Infinity Emit tweets located between 2 Acoustat panels driven by Dan's version of a servo amp. My room wasn't big enough for woofers. The system I copied was that of Dr. Marty Wax. He had a 30wpc Bernig for his tweets and big Rowland monoblocks for conventionally driven panels, but he had a pair of large Entec woofers. That system was the closest to live, I've heard. BTW, the panels were driven full range on the bottom with the woofers augmenting the bass.
fleib