Microphonic pickups - pot them? What if they are already potted?

redeyedjim

Gold Supporting Member
Messages
2,350
I have a guitar that I reworked and rewired a couple of years ago, and I have what I think are some issues with pickup microphonics. There's no squealing, but taps to the pickup ring are easily and clearly heard as percussive sounds from the amp. It's been doing this since I finished the wiring a couple of years ago, but I am finally sick of it and want to fix it.

The guitar has three Dimarzio pickups: an SDS-1 (neck), a Super II (middle), and a SuperDistortion (bridge). All pickups were purchased new after 2012. One wrinkle that may be important — the guitar also has an onboard buffer/unity gain preamp.

The microphonics I am hearing are the same regardless of the pickup(s) selected. The guitar does not squeal, and sounds good, but the microphonic pickup ring (and body) doesn't seem right. All three pickups are mounted to the same 360HH brass pickup ring, which has been chromed:



Any ideas on how to remedy this? The guitar's internal wiring is complicated (basically a clone of the J. Garcia "Tiger" wiring, per Mike Wald) but otherwise appears to be functioning correctly. I have gone through the grounds carefully and do not believe I have any grounding issues. It's just picking up more sound than I want it to.

I have a question out to Dimarzio to see if these pickups are already potted. If they aren't, I assume that's the next/best thing to try. But if they are already potted, what's my next move?
 

walterw

Platinum Supporting Member
Messages
38,989
you've discovered the issue with metal pickup rings!

is the routing under there still individual holes for each pickup or is it one big bathtub rout? if it's individual for each pickup with wood "bridges" between them, then you might be able to lock down the metal plate a little more by pulling it off the guitar and bending it ever so slightly down in the middle, so that the screws along the outer edges there serve to press the middle areas hard against the wood. (the same trick works on ringy vintage tele brigeplates)

if it's a bathtub rout, so that the pickups are essentially sitting in a brass trampoline suspended over the face of the guitar, then i suspect you'll have to live with it. hey, a little microphonics can be cool, it adds a bit of liveliness to the sound.
 

redeyedjim

Gold Supporting Member
Messages
2,350
Thanks, Walter, that makes sense. The space under the mounting ring was created with a bathtub rout, so I guess there's not much I can do on that score. The trim ring itself is made from a sturdy and thick (0.1250" or 0.1875") brass plate, and it sounds like that's doing a great job of transmitting clicks, taps, and other vibrations to the pickups. I've lived with it this long and can continue to live with it, but maybe I can find some ways of reducing it? The pickups are currently mounted using standard pickup mounting springs, so maybe swapping those out in favor of surgical tubing might reduce vibrations transmission a bit? I also have a prototype of the brass ring made from a dense plastic; it isn't as attractive as the chromed brass, but it might not transmit vibrations as well, either. Any other tips?

Thanks for your help.
 

Chris Scott

Member
Messages
9,232
Don't know if the body rout is nice and flat or not, but if it were on my bench w/ the same issue, I'd try whipping up a couple of pieces of scrap wood to mock-up under there, one in-between the neck/middle, the other in-between the middle/bridge, say 3/16" X 3" or so, with maybe a little strip of foam or something and just tall enough to be compressed snugly between the body and p-guard.

Try it and see if it chages the resonance in a way you can live with, then if so make it permanent.
 






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