The SA-100 is a power amp, not a preamp, and is definitely worth more than $500 when its rebuilt. You can certainly get fully working original SA-100s and SA-200s for around $800+, but they are not the same thing as the rebuilt units.
When Alta Vista rebuilds these units, they're not a rebuild-in-kind. They're basically a replacement of most of the electronics. Because Alta Vista operates on a very different business basis than Counterpoint did, you get a considerably higher value out of the rebuilds than the original units.
Most of the Alta Vista rebuilds are VERY extensive and QUITE expensive - the maxxed out rebuild of an SA-220 runs $3200+, plus the $800+ you put in to get the original unit. (There are less invasive $1500 rebuild options too.) I've heard the upgraded SA-220 and SA-5.1s, and they do sound REALLY smooth, but at those price points you have to consider a lot of other things as well, and the competition is quite stiff at that level.
However, the $1000 rebuild on the SA-100 looks like a pretty good deal, since the result (based on the SA-220 upgrade) is likely to be more than competitive with anything you can get for $1000-$1500.
When Alta Vista rebuilds these units, they're not a rebuild-in-kind. They're basically a replacement of most of the electronics. Because Alta Vista operates on a very different business basis than Counterpoint did, you get a considerably higher value out of the rebuilds than the original units.
Most of the Alta Vista rebuilds are VERY extensive and QUITE expensive - the maxxed out rebuild of an SA-220 runs $3200+, plus the $800+ you put in to get the original unit. (There are less invasive $1500 rebuild options too.) I've heard the upgraded SA-220 and SA-5.1s, and they do sound REALLY smooth, but at those price points you have to consider a lot of other things as well, and the competition is quite stiff at that level.
However, the $1000 rebuild on the SA-100 looks like a pretty good deal, since the result (based on the SA-220 upgrade) is likely to be more than competitive with anything you can get for $1000-$1500.