I'm Back! Well here's my dilemma. I have about 15 hours of burn in time on the Psvanes. I can still hear a Hum from across the room. The Set that measures 45 seem to be a little louder than the 55 set. Tried rotating the two 12au7's, tried a used set of 12au7's, no change. The Hum is the same wether the stereo is turned on or off, volume does not affect the hum. Checked for ground loop, unplugged every thing except the amps, also tried to simulate a cheater plug by wrapping electrical tape around the ground lug on the AC plug, no change. Reinstalled a set of Gold Lions in one amp, no hum unless you put your'e ear up to the speaker, the other Psvanes can still be heard across the room. Don't think any amount of burn in time would help them. Any suggestions? should I continue to run them and see what happens or should I contact the manufacturer and return them. Thanks!