Interesting thoughts Frank. I don't recall ever hearing a Bogen amp, hooked up to any kind of High-End source(s) or speakers. I can't help but wonder; how many others have. Based on my experience(repairs/communication installs): Their circuitry was always very simple, which would lend itself to good sound, and the quality of a unit's transformers, has much to do with it's sound. It would be fun to do an upgrade on a pair of their DO70 tubed amps, replacing all the antiquated resistors, caps, inputs, output terminals, wiring and bypassing the junk level controls/selector switches, to see how they would fare(sonically).