Foster-9, if you're looking for used amps there's a lot of selection:
Any Krell amp. There are several Evolution 302s available, as the 302e just came out. The older FBPs are great too. Any higher power than a 300-series amp just seems like overkill to me.
Any Levinson 33x or 43x-series amp, or any later models. My one caveat with Levinson is that service can be complex and expensive. My 334s have been bullet-proof, but in current dollars remember that even the low-end 334s would likely be $10K each.
The Parasound JC-2. These have always tempted me, and they are occasionally available used. They were $3K each when they were introduced in 2003, but now they retail for $4500 each.
Bryston, Ayre, Pass Labs, Classe, Coda, Boulder... mostly North American stuff, since high current amps seem to be a largely western hemisphere thing. Of course, these are all very expensive amplifiers. For used equipment there's a good economic argument for Krell & Levinson, simply because there's an active market and these amps retain high resale values. Any of them will be costly to service.
New high-current amps that claim to double power with halved impedance seem to start in the $5K range and go up. Way up. Krell and Levinson seem to think $20K amps are mid-range nowadays. Mostly I think what we're paying for is fancy aluminum casing work and Swiss-watch-class build-quality in a North American factory. (Most of the components will be imported.)
IMHO, the most important spec for a properly design solid state amp these days (well, at least the one I look at first) is signal-to-noise ratio. Almost everyone has low distortion and high power, but noise is a different story. Most amps are rated at something like -100db below full power, and since they usually have 25-30db of gain we're talking in the range of -70db of noise, sometimes worse, below 1 watt of output, which can be audible with some speakers, especially if the frequency distribution of the noise amplitudes include a good bit of output below 20KHz. Maybe it's just me, but I find a dead-quiet background attractive. The latest Krells are very low noise, for example, the older Levinsons less so.
Any Krell amp. There are several Evolution 302s available, as the 302e just came out. The older FBPs are great too. Any higher power than a 300-series amp just seems like overkill to me.
Any Levinson 33x or 43x-series amp, or any later models. My one caveat with Levinson is that service can be complex and expensive. My 334s have been bullet-proof, but in current dollars remember that even the low-end 334s would likely be $10K each.
The Parasound JC-2. These have always tempted me, and they are occasionally available used. They were $3K each when they were introduced in 2003, but now they retail for $4500 each.
Bryston, Ayre, Pass Labs, Classe, Coda, Boulder... mostly North American stuff, since high current amps seem to be a largely western hemisphere thing. Of course, these are all very expensive amplifiers. For used equipment there's a good economic argument for Krell & Levinson, simply because there's an active market and these amps retain high resale values. Any of them will be costly to service.
New high-current amps that claim to double power with halved impedance seem to start in the $5K range and go up. Way up. Krell and Levinson seem to think $20K amps are mid-range nowadays. Mostly I think what we're paying for is fancy aluminum casing work and Swiss-watch-class build-quality in a North American factory. (Most of the components will be imported.)
IMHO, the most important spec for a properly design solid state amp these days (well, at least the one I look at first) is signal-to-noise ratio. Almost everyone has low distortion and high power, but noise is a different story. Most amps are rated at something like -100db below full power, and since they usually have 25-30db of gain we're talking in the range of -70db of noise, sometimes worse, below 1 watt of output, which can be audible with some speakers, especially if the frequency distribution of the noise amplitudes include a good bit of output below 20KHz. Maybe it's just me, but I find a dead-quiet background attractive. The latest Krells are very low noise, for example, the older Levinsons less so.