thanks. We have owned the same pair Quad ESL-57s, bought new in 1979. Before that, another set that we sold because they were copper, we wanted black. If you really want some fun, ask if the copper or the black Quads sound better. We have run them successfully with a Quad 405 current-dumping solid-state (100W x 2), and now with an Audio Note Cobra tube integrated (28W x 2). The Quads sound much better with the tube amp and there is plenty of power. We recently replaced the Jolida JD100 tube output CD player with the tube output Audio Note CD 3.1x/II player. Again, a remarkable improvement. I think electrostats, at least ours, are MUCH happier with tube power. You can purchase used and refurbished Quads from reliable people. The sound is something to experience - so transparent, it is spooky.