When I owned Vandersteen 2CE's I drove them with Quicksilver Silver 90 mono's. I have heard these amps drive Vandersteen 3's and they will work well. I don't know if you can get them used for $1000. I sold mine for $1100 easily. Subsequently, I needed to go to a stereo tube amp and I bought an AMC CVT2100as from retrodaze audio for around $700 and it is very close to the Quicksilver in sound quality. It does have 10 wpc less than the Quicksilver (80 vs 90) but that may not make much difference. I don't think you can use the 60 watt Quicksilvers with the Vandersteen 3's as they need some power to work effectively.
