The Amp Game,

Can't say I know anything about the sony amps, the Adcom mono's are pretty old, I would check with Adcom and see if service can still be had on them. They got a good review in stereophile years ago, class B if I recall. Aragon 4004 can be had in your price range, Belles 150a hot rod is for sale on audiogon also. I don't know the output of your sony, you will need to factor that in your choice of amp if you are going to go without a pre-amp, your speakers at 84db could be a problem in passive also.

Parasound amps are excellent used values and offer a good amount of power and current; reliable, too. Well within your price range. You could even buy one of the new Parasound Halo amps, I believe, for around 800 (the 100 watt model; good amp from what I hear),.

The hca 1206 is interesting as you can bridge four of the six channels for LOTS of current and power and still have another pair of stereo channels left over at 135w/4 ohms and 200 into 8 for each channel. Bridging takes it up to 350 watts into 8 ohms; it works.

Be paitent and find an old S300 II Stasis amp from Threshold.

They can be had at your limit, it will take a few months.
I saw an S500 go on e-bay last week for a kilo buck.

Also if you can live with lower output the Aleph are awesome amps at about that price used, or a kilo buck new.

jeff

If you don't mind vintage tube gear, you can get a good shape Harmon Kardon Citation II ( 60 Watt/ch ) tube amp for that price and it will blow everything you listed away.

You could also look into an Odyssey Stratus. You can get a used one in your price range. I doubt you will be disappointed, unless you need a lot more power. But that depends on listening levels, etc.