I received an e-mail question about the noise fixes/tweaks and I'm concerned that I may have mixed some people up.
Just to be clear, here's the essence of the diode/rectifier and snubber cap tweaks:
The BY228GP diode/rectifiers and snubber capacitors are for D5, D6, D7, and D8 – the heater voltage supply. The 1N5062 diodes are in the B+ tube supply and are already high-voltage, general purpose type – no need to change those. I also tried snubber caps across the high-voltage diodes and the noise reduction – if any – was inaudible. So, the snubber caps have no effect there, either.
What is happening to produce the 180Hz ripple noise is that we originally used high-speed Schottky’s for the heater power supply rectifiers (D5, D6, D7, D8). As Dsavitsk recommended each of these mods to me, I went from snubber caps only to changing out the rectifiers + snubber caps. I'd say the contribution of each toward reducing the noise is about 50%. IOW, you should do both.
P.S. All the kits and built Torpedo's I've sold since first mentioning this have included all of the tweaks.
Edited by tomb - 12/6/13 at 3:53pm