best used amp for 300- 400


I have a system composed of a rotel rcd970 cd player, rc990 preamp, rt940 tuner, acoustic reasearch turntable with denon mc cartridge and old infinity Qe speakers and am looking to replace my amp an old dying adcom gfa-2. I have heard a rotel rb 980 in the system and it was decent but not great i am trying to find an old bryston 3b but any suggestions would be welcome, my price range is less than $400 including shipping so closer to $350 would be ideal. I listen mostly to classic rock and ska, so i want power and good bass but also want good upper frequency perfomance as well. Thanks
sailor720
thanks for the responses, after reading some reviews the b&k sounds like the best because my system tends to be a little too bright .
I own/have owned B&K ST140, ST1400mkII, Reference 4420 amps, and all are excellent. If you do investigate the ST140, there are two versions cosmetically (one with blue racing stripes, other black with gold rack handles - I like this one better). The ST140 is a minor classic, hard to go wrong. I believe the 202 is from the same series so would be a solid amp as well.

Interconnect/speaker cable choice can also tame a bright system.

cheers,
mwilson
Used PS Audio amps (200, 100cx, etc.) run in that price range. They can sound a little hard at times however (although Paul McGowan claimed to have been using ARC electronics to voice his equipment). The Bryston is a good choice, too - I used a 3B for years with my M-L Sequel IIs and (now-extinct) GNP 220s. I'd also look at the Marantz MA-700 blocks; they're pretty cheap, come recommended (haven't heard them myself) and you can save $$ on speaker cable by putting them right next to your speakers.
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Viridian is correct about the ST-140 having trouble with lower impedances, I have experienced this in extreme cases. I wouldn't pair it with a 4ohm speaker on a bet. The bass is not as big as "muscle amp" bass, but I find it voluminous with correct speaker matching. I can't speak to the Infinitys you own. "solid state like tubes" - this guy is right on. Probably explains why I moved up to a CJ Sonograph 400 in my main rig.

There's also a Mccormack DNA .5, just listed for $550 (steal)... out of the pricerange, but damn!