Holland Amp

[tubeswell]

Methinks it definitely must be unwanted EMF coupling. If Pan movement options are highly constrained, maybe try another pan, (or rotating the PT ?)

[sonicmojo]

It is not an issue with the pan on its side so there it stays. Other pans did the same thing, I tried several.

Here it is in its cab. Still need to sort out a ground loop - slight 120Hz hum when volume turned way up. I may try moving the grid stopper placement on the main input coax or maybe eliminate the ground shield on the wire altogether. The slight hum seems to be induced at the input jack. I tried isolating the jack, moving jack ground points, etc. Still fighting it a bit. Could be heater imbalance. It is very minor but I'd like to solve it so will try a few more things.

svfinalcab.jpg

[martin manning]

It won't be heater hum if it's 120 Hz. Maybe confirm the frequency. Are you sure there isn't some source of noise in your work area? That might explain the reverb pan anomaly.

Cool piece!

[sonicmojo]

I’ve tried a couple of areas in my house. I think I’m picking at nits on this, most of my amps have some noise at full crank. I think I’m just becoming a bit perfectionist which is good and bad when you want to move on to the next one.......

[Aaron]

Try isolating the reverb tank input. The last few amps I’ve built have had a grounding issue, was the reverb every time. Have never had an issue before, but I did have some older ones, don’t know if new tanks a built the same?

Aaron

[jackzucker2000]

thanks for your help.

[T Wilcox]

if you have a meter I'd suggest checking continuity to ground from the pots since it appears to be a recurring problem. May or may not be the issue but easy to check and eliminate as the cause

[jackzucker2000]

thanks, should i just run a bus wire across the back of all the pots on the front?

[T Wilcox]

thanks, should i just run a bus wire across the back of all the pots on the front?

I'd say only if necessary. Confirm that is the problem first