If it works without issue, I'd keep using it. I've had several Carver amps over the years, not quite as long as you. My oldest, an M-500, went up in smoke several years back but still have two M-500t amps, altho one has an annoying transformer buzz now (and a fairly recent appearance) so took them out of that system. Still use a C-1 pre-amp in a system with active speakers, works fine.