(Login Nafana) Forum Owner Posted Aug 30, 2007 3:17 PM
Yes, audio purists insist that tubes (er- "valves" to you!) "sound better". And there is something to that in certain cases- when a transistor is overdriven it goes into hard clipping- squaring off the waveform and producing heavy distortion. But when tubes are overdriven they have a softer knee which rounds off the corners rather than clipping them- so while there is still distortion- it sounds less harsh with fewer harmonics.
As for mercury rectifiers, I have seen plenty, Eric- I worked with a 50-KW AM transmitter for years that used 6 GL829s in a full-wave three-phase bridge outputting 15.3-KV at 6-amps. They would pulsate real pretty with the modulation! But they were also a pain in the neck with arc-backs so we eventually converted them to silicon.