Help with Vintage B&K Power/Pre Amps


I have a ST2140 power amp and a PRO 10MC Sonata Series preamp... thought I had trouble with one of my tweeters (right speaker sounding overly bright to the point of listening fatigue)... a friend brought over a pair of B&W monitors and after plugging them in, the right speaker had overly bright highs as well... anyone have any idea what might be causing this... do I need to send the 2140 into B&K to diagnose, or maybe the PRO 10MC, or both... any suggestions appreciated... this journey down the vintage equipment road can be challenging... thanks in advance.
tapar1
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.
Tapar1, Is your the Pro10 preamp the model with the red/blue or black/gold writing on the black faceplate or the machined black faceplate with grayish inlaid color where its sort of recessed? There were early and late generation pro10s.

Depending on which version pro10 it is, if you decide to let go of it, I might be willing to take it off of our hands if the price is right and to fund your next preamp purchase.
It's the one with the red & blue on the faceplate... just sent it in for servicing... not sure if it is the early or late model...