Infinity FET Preamp rebuild

I’d recommend his accomplice, Arnie Nudell. Regrettably, Arnie has also passed away. 

The “right guy” would have been John Ulrick, the lead designer at Infinity Systems at the time. He also designed their class D amp known as SWAMP. He went on to form Spectron Audio. He passed away a few years ago.

The likely issues might be aged parts. The solution would be to replace all resistors, caps and FET’s with premium parts, and replace the internal wiring with quality Dueland wiring. Any competent service shop should be good enough to handle this work. Should not run more than $1,500 in parts and $500 in labor.