Holy crap, it works!

[Steve Conner]

By far the most important thing is that the HV CT should connect directly to the negative terminal of your first filter cap. Run a wire between these two points, and don't connect any other stuff to this run of wire, except for one other wire coming off the filter cap negative terminal to hook up to the rest of your ground system.

[lmolter]

To MWJB, I had it this way originally when I had the hum. However... I did not have a buss wire across the pots and I did not ground them and the eyelet board to the input jack. So, I guess in retrospect, I did NOT have it grounded properly.

I'm waiting for some parts (one of the jacks did not short and I need new 68K's) and I'm going out of town, so it'll be a week or so before I can button it all up again and see.

[Kevin]

Lead dress in wiring these amps is very important. Grid wires should from board to tube should be as short as possible. I find that plate to board wires running adjacent and parallel to grid wiring can increase the noise/hum. Crossing wiring at 90 degrees helps. If you can find a blackface fender or a pitcure of it, carefully route your tube to board wiring to match.
Also, star grounding, allthough time consuming makes for a very quiet amp.

Good Luck,
Kevin

[lmolter]

Thanks, Kevin. The amp has been done for a while now and is virtually hum- and hiss-free. Per the various members' recommendations, I carefully investigated my grounding schemes. Deciding that it was haphazard, I rewired all the grounds and eliminated the hum in the process. In retrospect, I believe the singular cause of the hum was the grounding of the bias supply to the preamp ground. In the course of my rework, I moved the bias supply ground to the main reservoir ground. And believe it or not, I used unshielded wire from the input jacks to the grid resistors mounted on the board, much like the original. No problem there, I guess.

Thanks for replying.
Larry