The Quad II's and Radford''s did and excellent job in driving electrostatics like the Quad 57's
It might surprise many people to know that tubes/valves are still used/preferred widely in professional audio/recording including valve microphones, cutters, compressors etc.... i.e. EAR Yoshino, Manley Labs, Tube Tech etc...
True. In an absolutely cost no object ( and somebody else to take care of my valve preamps when they start "cooking", most likely/preferably during "it is now or never" take of some superb artist that presents itself once in a lifetime ... ) world I would opt for HSDs, as I call them. In real world given budgetary constraints - no. Failing to make a once in a lifetime oportunity recording due to HSD malfunction - double no.
Yet - if you have the doe, don't mind becoming VERY valued customer of the power plant serving your location, protests from the enviromentalists - and want absolutely the best sonics imaginable - and need a power amp, look no further than Krklec OTL mono blocs with 12 PL 519 tubes per channel. A friend of mine has this behemoths and they simply mop the floor with anything else. If I undferstand it correctly, special built to order item only. From our neighbours, the Croatia.
Crackling sound of that many PL519s upon switching on, even more off - during the cooling phase, is simply - priceless. As it is the music played through this uber rare OTL in between.