Best Used under $300 2 Channel Amp

I sold Adcom for 6 years.Good sound for the buck.B&K is also good.NAD I am not sure about the series.Never a Carver guy.Newer version of amps pre's your talking those names.One question is how much use they got and if older if caps have dried out.I have some older PS stuff that I use for second system.The 4.6 was an $800 pre that goes for $250 give or take.The amp I have has plenty of current at 100 wpc and went for $1200 and now goes for $300-400.But again with older equipment your going to get better deals but age and use means heat and potential repair if not well built.I notice there is a Bryston 3B up now on 'Gon for asking of $400.There is a reason they gave 20 a year warranty.They are built like tanks.Maybe you could ask a better price.If you want FM the Adcom pre/fm combos are hard to beat at low price.
G'luck

If you are biamping, you really need 2 very closely matched if not identical amps. This may also require a pre with dual outputs. Y connectors will work but not as good many times.

A cheaper alternative is one big amp vs biamping? Personally, I'd rather have 1 really good 100 wpc amp than 2 cheaper/older amps. Also, are you aware that going from 100wpc to 200wpc will only gain you 3db? That's barely audible.

B&K, rediculous used prices.

I'd probably go for a used Adcom or B&K. Both are excellent values used!

You want a 2-ch power amp for <$300. You also need 2-ch. preamp. How much are you willing to pay for the pre--$200? That's a total of $500. You can get a new integrated amp for around $500 that is better than pretty much any used amp + preamp at that price unless you get extraordinarily lucky.

I have been integrating systems on a budget for 14 years. I have stacks of old surround processors, preamps, and power amps. Some work, some don't. I paid $200-400 each for the better power amps, and $200-ish each for a couple of preamps. These units were state-of-the-art when they hit the market.

They're all on the shelf now because I have a new Onkyo A-9555 integrated amp that I got from an authorized dealer w/warranty for $474. The Onkyo is faster, more transparent, organic sounding, more stable, clearer, and has a much lower noise floor. It can also deliver an incredible amount of instantaneous current, making the amp sound more powerful than it is. It's about 100wpc into 8 ohms and 200 into 4. You cannot bi-amp with it because it does not have preamp-outs, but you can easily biwire with it, and that's what I do with excellent results. In my experience, passive biamping and biwiring offer pretty much the same sonic benefit over single-wiring, minus the additional 3dB headroom you *may* get from bi-amping. (Another candidate would be the Cambridge Audio 640A v2 or 740A in the same price range.)

As I said, you'd have to stumble onto a rare deal for less to get better sound from the used market than what this amp offers new. And face it, Carver, Adcom, and Parasound are well-known and nobody gives'em away.