Blend, Vol, Tone, Hum... bzzzz

[Cayce]

Hey SD Forum;

I've got an old Melody Maker I cut a new pickguard for and loaded with SD Rails. I'm panning between Neck & Bridge with a blend pot(500k), following by a Master Volume(500k), then a Tone(500k/0.020mf Cap). This is a new setup for me and I'm bedeviled with an unusual amount of hum. Going straight into the Mesa it's really clean, though slightly thin. Engaging my Boss compressor pedal raises the hum, then engaging my Tube Screamer sends it over the top.
I adapted the SD diagram for two HBs, three-way switch, one volume & one tone, and thought I got it pretty well harnessed, but something's wrong. I'd like to get some advice if possible. I've included a diagram I put together of my circuitry.
I'd also Like to hear if I should open up the pot(s) with a higher rated resistance... maybe 1000k.

Thanks much. Great forum!

Cayce

 

[Funkfingers]

Re: Blend, Vol, Tone, Hum... bzzzz

Welcome to the forum. Interesting question.

What make/quality is the Blend pot? (I notice that your schematic does not illustrate whether the Blend pot chassis itself is grounded.)

Does the hum vary according to how the Blend pot is adjusted? If not, you have a grounding issue. Either a loop or some vital connection missing. (See previous paragraph.)

I do not believe that changing the volume and tone pots to 1 MegOhm will bring any improvement.