Sorry, no experience with tubes => Class D . . . I have Focal 1038be powered with a Yamaha P7000s, 750W x 2, 20Hz-20kHz. The "pre" is a Yamaha RX-A1050 AVR. Source is a Yamaha BD-A1040 universal player. CD/Blu ray/SACD all sound great, never run out of power. The pro amp's fans have never come on. I've wondered what, if any, improvement I might hear with PS Audio's Stellar M700 monoblock power amplifier ($2998/pair); I paid $599 for the Yamaha.