Single coil hum



Most of the guitars I've owned over the years were equipped with humbuckers, so my experience with single coil hum is limited. I have a baritone with soapbars that hums unbelievably when I'm not using both pickups (either parallel or series). The tween settings are fine for me: enough twang and woof to make me happy and dead quiet. But I was wondering: what helps? Would shielding the pickup cavity and control cavity help? Do the hum cancelling and "virtual vintage" p-90's sound good?

Are there any other strategies for dealing with it? Or is that part of the p-90's "charm", like the puddle of oil beneath a BSA motorbike?
Sounds more like a grounding rather than a shielding issue... I have high output Rio Grande P90s in a couple of builds and they don't produce any more "hum" than a Strat...
Well, that may be the problem. Also, I don't have a decent base of experience to judge how much hum v. a strat or tele. It changes as I turn towards or away from the amp.
Get away from:

Florescent lighing
etc etc

TV's and computers especially... can throw a loud hum a long way.

Id agree with spaldingrules

try the dimarzio vv p90's they are hum-bucking p90 that should sound like a a normal p90.


Read and analyze, gentlemen... Hum is only present when P90s selected individually, but NOT with toggle in "both" position, and additional parallel/series wiring/switching. So changing the P90 OEM would have no effect on the problem...

Does the OP have a copy or can draw a picture of the how all the wiring is done? Seems to me there is a grounding problem, else you would get the hum when toggle was in "both" position as well...
jackthehack said:
Sounds more like a grounding rather than a shielding issue... I have high output Rio Grande P90s in a couple of builds and they don't produce any more "hum" than a Strat...

I agree.. Does your amp have a three prong plug? Do the receptacles its plugged into? This still may not guarantee a good ground. If you can, run a wire from something you know is grounded to a screw that touches the metal bits on your amp and see if it helps. I caution you to be very careful !! PLEASE !!

Also, didn't those pickups actually use an Alnico Bar Magnet for the blade instead of metal. I may be wrong but I think that style of pickup building creates more noise. I had made one that way and it was quite noisy in comparison to others.


*edit* I went back and looked at that guitar. It had Alnicos intead of screws. I think this still may be a bit noisy due to the config of the coil. It's pretty fat compared to height. I would still look at grounding first.
It appears that one of the PU's is RWRP - no noise when both are selected. Therefore a humbucking or stacked P-90 would be a solution.
sounded to me like one pickup is RWRP so they cancel hum in the "both on" position, in which case he would benefit from having two pickups that were hum-bucking.

I'm pretty confident the guitar is properly grounded. The string ground is attached, and the hum doesn't change if I'm touching the strings or not. The outlet the amp is plugged into checks out ok: correct polarity and ground. I've had guitars that were improperly grounded, and they hum regardless of pickup selection. I may have some ground loop inside the guitar.

I think CB is right: the culprit is RF. As of right now I live in a condo below a neighbor who has no fewer than 5 tvs in a two bedroom unit (god forbid the kids should have to share) that they leave on when they're not home. So, getting away from RF is a trick and a half. I've considered turning my music room into a giant Faraday cage. I've also considered building a giant coil on the ceiling and gaussing the hell out of all their TV's at once. My wife came up with the utterly boring solution of finding a bungalow we can afford. So we're moving in two weeks.

Definitely considering the VV p-90's. You guys like the VV's? They sound like single coils? The virtual p-90 doesn't look the same, but that's cool.

Are the strat/tele VV's another stacked coil design, or is there some secret sauce involved?

If the root cause were external RF sources like a computer or fluorescent lighting, you'd STILL get the hum, and maybe louder with the toggle in the "both" position.

While having (typically) the neck P90 RWRP DOES cancel noise/hum when both PUs are selected, that has no bearing on P90s selected individually.

None of y'all are displaying sufficient troubleshooting skills to get a job working for me,

I still want to see a wiring diagram/drawing of the circuit implementation.
Might add that amps can make yer geetar hum too, if they're close to the amp.

"I poked'n stroked till my wrist got numb
But I still didn't hear no Dinah-Moe Humm,"

Frank Zappa, Joe's Garage
i'd agree that it's a grounding issue. sheilding will help hum but isn't a fix for a bad ground. my experience is that if the noise is bad enough to complain about it's not the pickups. unless you play standing very close to your amp or a tv or florescent lights.

most p-90's are sheilded on the back side by a steel plate like a humbucker. they useually have a two conductor coaxial cable. the outer conductor must go strait to ground. this sheilds the pickup. to do serial switching you must have a  3 conductor cable.
disconnect the pickup coil from the back plate and pole peices. you can use the cable from an old set of head phones.
the bare wire in the cable should always go from the back plate to ground and never be involved with the switching, ever!.
if this is not how your's is wired you must change one. you can have the other permanantly grounded.

this forum can asist you further if you give some details on the circuit. what switch/switches did you use? a blade style 4 way? how many poles?
a detailed scematic would be especially helpful