Two pickups, four coils, two series/single/parallel switches and life sucks.

[David King]

I'm working on a very old bass of mine that had two humbuckers with un-color-coded wiring. I tried rewiring the whole thing this spring but it's still not right.
With both switches in parallel mode the hum is gone in both pickups and all is in phase -good enough.
With both pickups in single coil mode, pickups are in phase but very noisy singly and together. Not so good.
In series mode both pickups are in phase but noisy singly and together. This is a real problem.
Where do I begin...
OK I must have two N or two S coils in the single coil mix. How can series mode be in phase but noisy?
Are the magnets flipped? That would be too bad because they're ceramics and they're cast in resin.

[the great waldo]

Hi David

Get your old analogue multimeter out and start doing the clonk test with a big screwdriver on the coils with the multimeter set on K ohms and see which way the needle swings. This sort off stuff also does my brains in, even after 30 years.

Cheers

Andrew

[big_teee]

Not exactly sure how your switches are wired up.
Sometimes all you need to do in split single coil mode, is change from switching ground to the coil to switching output.
That would select the other coil, and a different polarity.
Heres a guitar layout that might work.
Trey Anastasio's Guitar Wiring
GL,
T

[David King]

Thanks Andrew and Terry,
The 2 switches are on-on-on types.
I left my analogue VOM back in the old country unfortunately.
Trey's guitar uses three switches which I don't have room for, also the owner is already confused by the existing two. That said it's a clever system that allows coil tapping from either series or parallel configuration. I wonder if Paul Langedoc originated it...
I'm still struggling with how the pickups could be in series, in phase and noisy all at the same time... If I switch one coil's polarity to cancel the noise that will put them out of phase -no??

[big_teee]

In series you have two options.
Example:
both coils south, or north up, both eirher CW, or CCW.
The other option is RWRP
One wired South up either CW, or CCW, and one wired North up either CW or CCW, the opposite of the first coil.
If both coils are same up, and same wind direction then they are in phase but not noise canceling.
RWRP gives phase, and noise canceling, provided you get the RWRP wired correctly.
I will try to draw out your two switches, and pickups, and see what I can come up with.
If you could scan us a layout, that would help.
T

[big_teee]

Do you have two switches like this?
One for each pickup?
Are all four coils wound the same direction?
Did you use 4 wire hook-up on the P/Us?
https://www.google.com/search?q=sche...XTB1c9BJR-M%3D

[David King]

Look at the 5th schematic down on this page:
GuitarElectronics.com - Pickup Selector & Mini Switch Terminal Connections

[David King]

Here's what it's supposed to look like
GuitarElectronics.com - Guitar Wiring Mod-Humbucker/North Coil/Parallel

[big_teee]

Thanks Dave!
I will draw on that tonight, Now I have to go mow pasture!
Later,
T

[David King]

Happy mowing. Magnet polarity checks out so it's all down to finding the right wires. My friend Dave Meadows (Audere Audio) reminds me that any stereo recording software that shows you wave forms can show you pickup coil output polarity.

[big_teee]

I drew it up and beat on it a pretty good while.
The best I see you can do with two of those switches, one for each pickup?
You should be able to get series, and all coils parallel.
In split single coil mode, the best I could see you will get, is both coils in phase but no hum canceling.
I tried moving the wires around on the schematic, but it breaks the other series mode.
Also a drawback of that layout, is no way to disable one pickup at a time.
You may want to opt for a LP type 3 way switch, for pickup switching, and use push/pull POTs to get the other 1 or 2 switches, and try the Anastasio layout.
With it you can play the pickups one at a time, both together, with parallel, Series, etc.
GL,
T

[big_teee]

Here's the Layout I made.
Wired like this you have Series, parallel, and single Coil Split without Hum Canceling.
Discuss away!
Pos. 1 Series
Pos. 2 Split SC
Pos. 3 all coils parallel
T

[David King]

Thanks Terry,

I'm not sure how but I have used this schematic on dozens of basses and always managed to have the two single (or split coils) cancel correctly.
As these are all basses, most of them have pickup blend pots so pickup selecting isn't a problem.

[David King]

Update!
I checked the string ground and lo and behold the strings were not grounded through some fluke. I had the bridge connected to the shielding in the pickup and control cavities and the pickup drain wires were connected to that and all the pot and switch cases but no actual connection to the ground at the jack.
Now grounded, the pickups are quieter in series mode. The pickups are not hum canceling in single coil but I can live with that (And I'm pretty sure that Terry is right about not being able to achieve that with this schematic).

So first things first - Always check for a string ground when determining the sources of noise.

[big_teee]

I think I figured out some wiring options.
If you wire one pickup inside out(regular SD wiring)?
Wire the other pickup Outside in like the Anastasio diagram?
That still gives proper polarity in parallel, and flips one over in Split SC mode.
I tested the inside out, and the other RWRP in my SG test guitar and the phasing was still correct.
The Bridge P/U is inside out, and the neck is wired outside in RWRP.
That allows to pick the two inside coils in Split SC mode, giving RWRP, with hum canceling.
See Layout.