I cannot say what would be the very best match for your ATC 35's, but my Perreaux 2150 amplifier and SM-2 preamp work splendidly with these speakers. I have had the 35's in my system for well over one year, and I couldn't be happier. The Perreaux amplifier, while old (manufactured in 1984), packs a tremendous, tight punch and it is known for its warm, tube-like sound. Whatever amplifier you decide to get, remember that the 35's require a lot of power. If you can find a 2150 to drive your 35's I think you'll be very happy. I certainly am. 'Hope this helps.
