I bought a PAIA Tubehead and, after fixing the underdesigned power supply, I got a real nice tube preamp. I'm far from being a tube expert but I know it runs the tube at about 35V by stepping up the 9V delivered from the wall wart. (Isn't this called "starved plate" design?) It's not the best sound but it's compact, relatively cool (low temp) and does wonders for overly clean signals.
I would think that most tube preamps are not MOTM compatible because the 10V MOTM signal levels would be too much for useful operation. I'd love an MOTM VC tube preamp! And maybe 250V in the circuit just isn't necessary.
John Speth
Molectron Detector, Inc.
http://www.molectron.com
mailto:johns@...