Update (since I essentially posted the same thing in an ad for another pair of 6C33c based monoblocks
hehe):
I bit the bullet and had custom wound and potted toroid power transformers made by Primrose Audio. I'm very happy with the price and quality of their work. nice trannies....
Sol went to town and made all the modifications to use the custom trannies. It reduced the complexity of the power supply a fair bit according to him since I now have exactly the right values he specified instead of having to make an off the shelf individual transformer work. It eliminated a number of individual Hammond EI core trannies to go to this single toroid.
The result? Dead silent performance. Inky black background. No hums, no buzzes, nothing. The amp also runs a fair bit cooler than before. After being on for a few hours I can still hold my hand on the metal top plate... before I'd singe the hairs on my arm if I got within 5 feet of the thing. Success!
Now that we've gotten that far, it's down to breaking the thing in and doing some listening tests. I want to try some different coupling caps as well to see which one I prefer. I have a bias going in that the Deulands will be my favorite... but we'll see....
hopefully I'll have a few minutes this weekend or can convince my wife to allow me to sneak away from baby responsibilities to bring them over to Rich's for his latest GTG and see what other folks think about them...
So far so good... it's only taken a few years
but it's looking like we might have developed a unique and good sounding amp...
