Audio Research High Definition Silver SP-5 D-52B - a chance to buy

I wouldn't bother. Opening bid is $360, and it might not work. Repairs would not be inexpensive. 

thanks @noromance I thought it was a great high end brand. 

Looks like this model is Solid State and from 1977. I’m not against SS but it’s not really what ARC is known for. That makes me a little less enthusiastic about this unit. 

FWIW, ARC is indeed a great High End brand. This unit does not diminish their reputation in the slightest.
 

Thank you @rhg3 I guess it’s not as sweet a deal as I thought.

I remember when these were introduced. They used so-called "analog modules" instead of tubes. They didn't meet a great reception in the market, particularly given that ARC was foremost known as a company that re-introduced vacuum tubes as "high end" home audio gear. I don't think ARC can supply the modules, which as I remember were like large circuits that were epoxied. And though I cannot pretend my sonic memory is good enough to remember what something sounded like circa 1977, it isn't the age of the units that is an issue. An SP-3 preamp (tube) is still desirable. I still have my Dual 75a (tube) amp that I bought in 1975, and with a recap and new tubes (which I have), I could put it back into service. It may sound a little "old school" euphonic, but it will still sound very good.