I'm big into home audio and theater and have a tube amp power my mains. I was messing around with different 12ax7 tubes that I have laying around. I have a sovtek, Tesla/JJ, groove tubes. The old sovteck was about the same output in bass on my SWR, it read about 88-90db on my radio shack meter playing the E string. At the same volume with the Tesla/JJ tube I was at 92-94db. I did hear a difference before I checked the meter. Would it hurt to use home audio stuff? Also I did find the cheapest place for tubes at http://store.yahoo.com/triodeel/index.html How are the svets and Electro Harmonic tubes? I'm using the svets on my home audio output tubes and it sound's pretty good.