Speaking of amps, my son used to critique amps for "Bass Player" magazine a few years ago. Besides working at the Princeton Plazma Labs on the fission reactor, he has been designing amps for a company he partially owns.

With all the advancements in technology, he prefers the sound of the old vacuum tube amps. He describes them as "warmer" in tone. It's nothing you can measure on a scope....it's just there to the human ear. Of course, warmer doesn't cut it in contemporary "music". Horse power is the major criteria.

Problem is finding the tubes. He said they're somewhat difficult to obtain. The indication is Russia is the primary source because they still have the old equipment for producing them. That was at least 10 years ago. Maybe things have changed. Dunno!