Are Mustangs Supposed to Hum Cancel with Both Pickups On?

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RoséBear
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Are Mustangs Supposed to Hum Cancel with Both Pickups On?

Post by RoséBear » Thu Aug 01, 2019 10:38 pm

I’m using the current wiring in the schematic below for my mustang. Are mustangs typically wired to hum cancel with both pickups on?

I just bought some SD Antiquities for this guitar. I noticed they weren’t really hum canceling in the middle position, so I tried swapping the polarity of the bridge pickup. Sure enough, hum went away, but the sound was now out of phase.

So does this mean I just need to switch the wiring ofBOTH pickups instead of just one, or is this commonplace for stangs & these pickups?

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mbene085
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Re: Are Mustangs Supposed to Hum Cancel with Both Pickups On?

Post by mbene085 » Fri Aug 02, 2019 3:04 am

Check the magnetic polarity on the pickups. They should be opposite each other. If they're the same, they'll never humcancel in phase. If they're opposite magnetic polarity, reversing phase just means switching the two wires on one of the pickups.

If you switch both wires on both pickups in a two-pickup scheme, you have functionally changed nothing.

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Re: Are Mustangs Supposed to Hum Cancel with Both Pickups On?

Post by Danley » Fri Aug 02, 2019 5:22 am

If your pickups are RWRP, series or parallel (in phase) would both be noiseless, while out of phase would have noise. Is it possible you’re mistaking one for the other?
King Buzzo: I love when people come up to me and say “Your guitar sound was better on Stoner Witch, when you used a Les Paul. “...I used a Fender Mustang reissue on that, dumbass!

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Re: Are Mustangs Supposed to Hum Cancel with Both Pickups On?

Post by RoséBear » Fri Aug 02, 2019 7:37 am

Danley wrote:
Fri Aug 02, 2019 5:22 am
If your pickups are RWRP, series or parallel (in phase) would both be noiseless, while out of phase would have noise. Is it possible you’re mistaking one for the other?
Not at all, I switched one of the wires to check and that very honky sound of out of phase is unmistakable.

I very simply took the wiring diagram above, and replaced the Japanese pickups with the SD antiquities. I’m not sure if it’s 60 cycle hum, it’s kind of a higher pitched buzz. It’s not that loud. Maybe interference? But then why would it become most prevalent with both pickups on?

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Re: Are Mustangs Supposed to Hum Cancel with Both Pickups On?

Post by Danley » Fri Aug 02, 2019 7:50 am

As an example, I posted a bit back about having noise despite RWRP and with both pickups on, that turned out to be related to the wiring of my house introducing a lot of noise. I deduced that in part by testing with a battery-powered amp. It’s possible better shielding in the control cavity might help; my only guitar that doesn’t suffer when I play at home has a bomb-proof shielding paint layer; problem is gone when playing out.
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Re: Are Mustangs Supposed to Hum Cancel with Both Pickups On?

Post by RoséBear » Fri Aug 02, 2019 8:27 am

Danley wrote:
Fri Aug 02, 2019 7:50 am
As an example, I posted a bit back about having noise despite RWRP and with both pickups on, that turned out to be related to the wiring of my house introducing a lot of noise. I deduced that in part by testing with a battery-powered amp. It’s possible better shielding in the control cavity might help; my only guitar that doesn’t suffer when I play at home has a bomb-proof shielding paint layer; problem is gone when playing out.
Interesting. That sounds about right. And with the AC on full blast that seems likely. Is that higher pitched buzz more along the lines of what you were experiencing with both pickups on? I have a gig tonight so I’ll let you know if there’s a difference!

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Re: Are Mustangs Supposed to Hum Cancel with Both Pickups On?

Post by timtam » Fri Aug 02, 2019 9:04 pm

The first thing to check is the magnetic polarity as mbene085 suggests. That will determine what your options are with the pickups as is when wired in-phase (ie whether you can get hum-cancelling, without string frequency cancelling). You can check polarity with a compass or by bringing the the pickup tops together .. same polarities repel, opposite polarities attract.

I believe vintage Mustangs pickup pairs (and some Mustang pickup manufacturers' products) are RWRP (reverse wound, reverse magnetic polarity, relative to each other). So one pickup has (upward-facing) north magnetic pole pieces and the other south, and they are hum cancelling (but not string frequency cancelling) when both ON, as long as they are wired in place (and switched) such that their winding directions are opposite. If your pickups aren't RWRP relative to each other, no amount of re-wiring will get you hum-cancelling when in-phase. Reverse/opposite magnetic polarities are the key.

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Re: Are Mustangs Supposed to Hum Cancel with Both Pickups On?

Post by RoséBear » Fri Aug 02, 2019 11:38 pm

timtam wrote:
Fri Aug 02, 2019 9:04 pm
The first thing to check is the magnetic polarity as mbene085 suggests. That will determine what your options are with the pickups as is when wired in-phase (ie whether you can get hum-cancelling, without string frequency cancelling). You can check polarity with a compass or by bringing the the pickup tops together .. same polarities repel, opposite polarities attract.

I believe vintage Mustangs pickup pairs (and some Mustang pickup manufacturers' products) are RWRP (reverse wound, reverse magnetic polarity, relative to each other). So one pickup has (upward-facing) north magnetic pole pieces and the other south, and they are hum cancelling (but not string frequency cancelling) when both ON, as long as they are wired in place (and switched) such that their winding directions are opposite. If your pickups aren't RWRP relative to each other, no amount of re-wiring will get you hum-cancelling when in-phase. Reverse/opposite magnetic polarities are the key.
Yessir, I’ll have to check this out when possible. I’m thinking it’s just a wiring interference thing, because the hum is not 60 cycle, but a higher pitched electronic buzz. I’ll have to try putting them together. I wired them exactly how Seymour Duncan specified so I can only imagine they’re in right

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Re: Are Mustangs Supposed to Hum Cancel with Both Pickups On?

Post by timtam » Sat Aug 03, 2019 2:01 am

RoséBear wrote:
Fri Aug 02, 2019 11:38 pm
I wired them exactly how Seymour Duncan specified so I can only imagine they’re in right
I hope that SD's Mustang pickups are RWRP relative to each other, but they don't state that AFAIK, eg
https://www.seymourduncan.com/pickup/an ... g-bridge-3

So the only way to be sure is to check the magnet polarities.

Fralin does state that theirs are RWRP ...
https://www.fralinpickups.com/product/mustang/

So do Mojo ..
https://www.mojopickups.co.uk/product/mustang/

Creamery say theirs can be made RWRP if you want ....
https://www.creamery-pickups.co.uk/cust ... ckups.html

Novak don't say ...
https://www.curtisnovak.com/shop/mustang-duo-sonic/

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Re: Are Mustangs Supposed to Hum Cancel with Both Pickups On?

Post by mbene085 » Sat Aug 03, 2019 7:14 am

Well, if you're not sure whether they're canceling hum or not, it's extremely easy to test even without a compass/magnetic direction check.

Just put on some OD, and flip back and forth from a single pickup to both in phase. If you hear a loud 60Hz component to the noise cutting in with the single pickup and cutting out with both on, you've got it working right, and you can then move on to troubleshooting the other electrical noise you might have going on.

It can be the power in the house, or the other devices in the house, and solutions can be guitar-focused (shielding all the cavities of the instrument), power-focused (power conditioners), or house-focused (finding and eliminating the most offending sources, like a particular fluorescent light on a dimmer nearby).

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