good used amp match for PSB silvers w/adcom pre?

Howdy all. Anyone have some experience that can stear me towards a successful mix, now that I have to replace the Adcom 535 that served me so well for 20+ years?

What I've got, working backwards: PSB Silvers, an Adcom 535 that now hums on the left channel, Adcom preamp tuner (whatever might have matched the 535 amp at the time), marantz cd.

I dearly loved the total sound that I was getting and I'd like to keep it similar, but I'm guessing 535's are just getting too old and failing. It sounds like maybe Rotel might be a good bet? I can only pony up $300 max.