Quote Originally Posted by hermanv
On the other hand, it is a fact that there is little change in the design of amplifier circuits and it is also a fact that tubed electronics continues to be popular for audiophiles long after the tube dissapeared from virtually all other electronic applications.
Even though a lot of people have, and continue to use old amp tech. Designs like the newer PWM tech from companies like Bel Canto and PS Audio, and the ultra-low distortion tech that is used in the Halcro amps, show that things have moved quite a bit. Even within modern conventional design, a lot of companies are moving away from global feedback, and are still managing to keep excellent specs. Other companies like Musical Fidelity are reevaluating some of the older tech. like choke regulation, and applying it to more modern tech like MOSFET output devices. Tubes are also being used in very sophisticated designs by makers like BAT, Audio Research, and others. A tube amp designer from 40 years ago wouldn't know what he was looking at if he opened a modern tube amp from Audio Research. Yes, older designs persist, but modern amp makers continue to push the envelop in design.