I have owned the SV83S model for a little over a year now. Recently, I have thought about selling it, but thank God, I changed my mind. This amp has so many 'possibilities' built right in it's design, that in order to replace it with another amp, you would have to know exactly what you want in that replacement amp! Just last night, I tried the single tube option (biased twice as high as the twin tube option), and was even more impressed by what I heard than with the other options. I will only use this for serious listening, since it wears on the tube significantly.
 Another suprise came when I opened the bottom cover just to take a peek, and discovered Steve's signature and some kind of serial number ending in 001 for one amp, and 002 for the other!
In the meantime, I have noticed the lastest integrated from Steve, and am very curious about the specs. and all the options(a pre-out jack for example).
 Thats enough for now, back to the music....Greg