You can just search for "potentiometer knobs" in eBay.I got an 100 hc ultra I’m looking for some were I can take it to get new knobs on it ! I tried to contact us amps no reply !
20+ year old amp probably wants new caps as well. Zed Audio does restorations of old amps and I'd imagine any of the other competent amp repair shops could get this restored/refreshed for you. Something like that is probably worth the cost to keep it in service.I got an 100 hc ultra I’m looking for some were I can take it to get new knobs on it ! I tried to contact us amps no reply !