Question regarding splitting interacting with phase (electrical and magnetic)

[56LPC]

I’ve got a project guitar (3-pickup LP) with a couple odd issues. One of the odd issues is me trying to do something off the beaten path without the experience to do it right. I’ve drawn up a unique schematic that seems to function as planned when testing with a DVM, but I’m hearing some things that contradict that.

Without diving into all the details, it is relevant to know:

• The M and B pickups are hybrids (one coil is 7k, the other is 4k)
• The M pickup is wired “inside out” so it should be noise cancelling with the B pickup when both are split. This Dimarzio diagram captures that aspect (https://www.dimarzio.com/media/662).
• The M pickup has the magnet flipped so it is out of phase.

What is odd:

• The easy one – my N+B sound is out of phase, and my M+B sound is in phase. I guess I lost track and either got the B pickup <or> the N&M pickups wrong when swapping magnets. I’m mentioning it in case the wiring of the M pickup interacts with this detail.
• The M & B pickups share a DPDT switch for coil split (down is hum, up is split). Measured at the output jack, both pickups behave exactly as intended (down is 11k, up is 7k for both pickups individually).
• Listening to them through an amp, the M pickup is working backwards (down is thin with a little noise, up is louder and fuller).

How can the *measurements* indicate the correct splitting is happening, but the *sound* acts completely the opposite? Does backward wiring somehow fool a meter? The sounds I get overall are cool, they’re just not what and where I intended. When in M+B position I am always combining a humbucker with a single coil and I wanted both pickups to match.

I know this is getting complicated and I am leaving out some context, but I figured I’d ask now in case there was a commonly known quirk of “inside out” wiring that I didn’t know before I start chasing incremental changes. Thanks!

- Douglas C.

 

[beaubrummels]

Welcome to the forum.

The meter is only measuring resistance of the coil wire, not phase of the whole system including magnets, so you will always get correct resistance readings but won't tell you anything about the phase relationship of two or more coils.

You swapped the magnets on all pickups? Are you sure you put the others in correctly? Maybe just try flipping the neck magnet, or at least check it's the direction you think it should be.

Without knowing the exact pickups, wind direction of each coil, it's going to be hard for anyone to answer.

 

[freefrog]

*The M & B pickups share a DPDT switch for coil split (down is hum, up is split). Measured at the output jack, both pickups behave exactly as intended (down is 11k, up is 7k for both pickups individually).
*Listening to them through an amp, the M pickup is working backwards (down is thin with a little noise, up is louder and fuller).

Hi Douglas and welcome onboard.

+1 on what Beau' said.

Also, the bit that I quote above suggests to me that you've wired the M pickup out of phase with itself. ;-)

I'd try to solve this by keeping as it is the split mode + swapping the two wires of the coil added for humbucker mode.

NOTE - It's normal for a DMM to read the same DCR in this case but if you had an inductance meter, you'd see a clear change in measurements...

Good luck in your tinkering. Keep us informed.

 

[56LPC]

Thanks to both of you.

Yeah, there's a lot of "story" to this that I left out trying to focus on the problem. The pickups are all leftover Gibsons I hacked into different configs:

• 57 Classic with one coil unwound and mag swap (4k / 3.5k / A5) in neck.
• 498T / 57 Classic hybrids with mag swap in middle (7k / 4k / A8x3) and bridge (7k / 4k / UOA5). Screw coil is 7k on bridge, slug is 7k on middle.
• 4-wire output from hybrid pickups, but 4-point modular connectors inline lead me to wire them 3-wire with the ground separate (red&black tied together on bridge pickup, white&green tied together on middle pickup - using Gibson color codes).
• They are all covered, so access to wires before that inline connector is a little bit of hassle.

It's pretty obvious I messed up the magnet orientation on one or two of them. I'm inclined to just flip the bridge magnet since the neck and middle seem aligned to each other now. Swapping the 4k coil wires for the M pickup is the exact kind of feedback I was looking for, but because of my 3-wire scheme I'll have to open the pickup to try that.

Sincerely appreciate the input, I got over my head with this project. On 2-hum guitars I keep the N pickup at 8 when combining it with the B, and the out of phase effect is pretty much gone at that setting, so it is actually quite workable for now. None of our songs need the middle pickup or out of phase positions (yet), and I have a show I want to use this guitar for next Saturday. I'll probably wait before cracking any of the pickups open since I'd likely make things worse!

I'll definitely follow up after poking at this, since the overall wiring isn't something I've seen online yet.

- Douglas C.

 

[56LPC]

Not that anyone was waiting on me for this response, but I wanted to thank y'all for the input. Turns out that Freefrog was right on the money. The 57 Classic coil of the middle pickup was wired backward. Both leads from the coil were black and I had trouble telling which was the start and which was the end. Works great now, and the split works as expected (with more output when in humbucking mode.

Unfortunately, the bridge pickup gave out near the end of that gig I delayed for! It got intermittent and I suspected it was the pickup itself since it crackled and sometimes came back when I knocked on it, but taking it out just now it reads fine. Seems like I have a bad solder connection somewhere on the bridge volume or tone controls to hunt down. Ugh...

Thanks again for the input- it was a massive help!

- Douglas C.

 

[freefrog]

Thx for the news, Douglas, and glad to have been helpful.

Hope you'll solve this soldering issue with your bridge pickup. Good luck again in your tinkering!