[TV MAN]

It must be eddy currents or something. I'm surprised how the placement of transformers in proximity to each other affect each other. I didn't have to connect anything at all except power to the power transformer and head phones to the secondary of the output tranny. Moving or turning either transformer even 1/8" makes a huge difference. I have the amp working pretty good now and am starting to do some experiments with different bias, screen voltages, tube types. I have a pair of older RCA speakers that one sounds pretty good but tweeters on the other are dead. Probably a bad crossover or something. It has NO audible hum or any other noise with my changes in a quiet room. I'm getting ready to build the twin this weekend so I can have a baseline to directkly compare to. It seems the more I use it, the better it sounds.

Edit: Mike, when I did the test, I had only the primary of the power trans connected to 120v, then only the secondary of the output tranny to my headphones. Every other wire from both trannys were loose (not connected). I could hold the output tranny in my hand and move it around the chassis and hear the changes. Now, how much hum is too much? Well, I could still hear a very slight hum/buzz in my headphones but with the final assemble, the amp is completely silent.