Unusual volume pot interaction with new pickups

[Mick Bailey]

I just fitted a pair of Bareknuckle PG Blues to a Heritage 335, replacing the original Schallers. The guitar worked perfectly beforehand.

With the new pickups each one on its own works correctly; smooth volume and tone, good tapering and no crackles, no volume jumps nor dead spots.

But, there's now an odd interaction when both pickups are selected. The volume change is very abrupt when either control is moved from 10 to 9.5, or 0 to 0.5. In between 0.5 and 9.5 the volume doesn't alter very much on either control. There's also a scratchiness at each end of travel like there's DC on the pots.

I called Bareknuckle and the guy was helpful but couldn't give me an answer, other than they're permanently wired out of phase and very low output in the middle position and may behave differently than expected in this guitar.

I've wired many pickups to be out of phase in the middle but never come across this. Any ideas?

Edit: the guitar retains the original wiring scheme - 'Vintage' wired.

[MarkusBass]

Description from their Website:
"Designed to replicate the tones of Peter Green's famous '59 Les Paul complete with legendary out of phase in-between tone."
So, it is not a bug - it's a feature

Mark

[pdf64]

Its worth verifying that there really isn't any dc, eg the 1st stage tube may have excessive grid current.

[Chuck H]

If the work was indeed limited to "just the pickups", as in, no other wiring was redone at all and just the pickup leads were lifted and replaced, then I would speculate that it's an anomaly of the phase and impedance particulars with the components. If there is any chance of a miswire that should be examined. If all the wiring is correct, lower value pots could help. If the guitar IS stock vintage though, the pot value is already as low one should go.

[pdf64]

Might tweaking the relative height of the pickups to each other have some benefit in reducing the degree of cancellation?

[Mick Bailey]

I tested the guitar using different amps and leads - Sessionette 75, Fender Pro Reverb, HH L100, + two of my own design amps. All with the same result. Pickup height makes no difference. They sound good, though the out-of-phase sound isn't to my taste with humbuckers.

I also checked beforehand if the neck pickup needed to be rotated 180 degrees as per PG's original. The answer is they're intended for normal installation, so that's how they're fitted.

It was just a pickup replacement - no other work. Lift one wire, replace with another. I've triple-checked the inside of the guitar to ensure the wiring didn't get twisted or pulled - this guitar is even tighter than a regular 335. I would expect any abnormality to show with either pickup selected on its own, but it's fine.

Whilst there's no buzzing or hum, the screened pickup wire has a high level of sensitivity, but only with both pickups selected. No noise if rubbed or moved with a chopstick but that distinctive electrostatic sound when rubbed with a finger. This is not the case when either pickup is selected on its own. I think this is related to the scratching pot noise.

[John_H]

Is one pickup noisier than the other when selected individually? Bad coil maybe...

[Mick Bailey]

Not any noticeable difference between the two with noise. I just can't figure this one out.

[The Dude]

Try flipping the wires on one of the pickups. It seems that the two are out of phase. Whether by design or not, if you don't like it, it should be easy enough to change.

[BasicBassVI]

I intentionally flipped the phase of the burstbuckers in my les paul specifically to get the Peter Green sound. When both pickups are paralleled (p/u selector in the middle) most o the "sweep" of either volume control occurs within about the first 30 degrees of rotation. This is due to the phase cancellation characteristics of the paralleled pickups altering radically with only a slight change in the output from either pickup. What the OP describe's with respect to the volume controls is completely normal. The "crackle" is not.

[big_teee]

He ordered an out of phase pickup set like Peter green.
I for one don't like out of phase pickups.
They always sound thin in pos. 2 to me.
If they are just a braided 2 wire, You won't be able to flip the polarity.
Not sure about your wiring.
T

[BasicBassVI]

I find that if I dial back the bridge p/u just a hair the tone fills up immensely while retaining the funky cutting mid and treble of the out-of-phase position.

[bbsailor]

I just fitted a pair of Bareknuckle PG Blues to a Heritage 335, replacing the original Schallers. The guitar worked perfectly beforehand.

With the new pickups each one on its own works correctly; smooth volume and tone, good tapering and no crackles, no volume jumps nor dead spots.

But, there's now an odd interaction when both pickups are selected. The volume change is very abrupt when either control is moved from 10 to 9.5, or 0 to 0.5. In between 0.5 and 9.5 the volume doesn't alter very much on either control. There's also a scratchiness at each end of travel like there's DC on the pots.

I called Bareknuckle and the guy was helpful but couldn't give me an answer, other than they're permanently wired out of phase and very low output in the middle position and may behave differently than expected in this guitar.

I've wired many pickups to be out of phase in the middle but never come across this. Any ideas?

Edit: the guitar retains the original wiring scheme - 'Vintage' wired.

Mick,

Look at this thread, post #4 on the MEF... http://music-electronics-forum.com/t34987/#post326355. This will explain how a slight movement, usually about one tenth of a turn, of either pickup volume pot can cause a shift in the notch frequency of out of phase pickups when used in pairs. Note the pot wiring (in the link above) is to give individual control of each pickups volume to enhance this out of phase, tuneable effect.

Joseph Rogowski

[The Dude]

If they are just a braided 2 wire, You won't be able to flip the polarity.

Hadn't thought about that. Yes, that would certainly throw a wrench in things.

[Chuck H]

AFAIK the Peter Green mod was simply to turn the pickup 180 degrees. That DOES flip the phase, but maybe not in just the same way as wiring a pickup out of phase. It flips magnetic phase. People sure fuss over this mod. I've never tried it myself. A pickup wired especially for this mod would be, what, just flipped 180 degrees and then have the lead switched from one side to the other for easier wiring? Anyone selling this as something special is yankin' yer chain or missed the point. So who knows if other shenanigans are at play.