Help with Vintage B&K Power/Pre Amps

I would be surprised if it was not more affordable to have the B&K serviced.
However before I went to the Classe I would check out Coda's new 7X.
They are using very high end double gated FETs and with their
high impedance produce a very tube like sound.

B&K is defunct. Try here:
http://www.bkcomp.com/support/

I recently attempted to contact B&K/ATI via telephone and email regarding an older model pre pro I was experiencing problems with.

They never bothered to return my phone calls or email.

The Pro 10MC was one of B&K's best products that they produced, it is a very listenable product, most likely worth a repair if not too costly. However, it is valued in the neighborhood of $250 right now. The Classe 50, is clearly a better product, but probably worth somewhere around $500 to $800. Neither of these products are considered bright. Tobb has recommended a terrific product, but it is new, you won't find a used one for quite some time and it runs around $6500.
At under $1000, I like the Muse 3 Signature or maybe a Audio Research LS9, both are single ended and balanced, both sound near dead neutral and both have remote.
You could could try a cables or a little less tow in on your speakers or both, that would effect high end and listener fatigue.... Good Luck, Tim

Finding a Classe CP-50 for $500 is extremely optimistic, unless it is in poor condition. Those go for more like the $900 range in good working and cosmetic condition. The published Audiogon Bluebook value exceeds that amount.