Idea on how to wire two spin a split pickups to cancel hum?

[Bowtomecha]

I have my bridge humbucker magnet reversed and wiring inverted so I can have the neck and bridge humbuckers cancel hum on the inner coils in parallel. I like the sound I’m getting. I have experimented with a spin a split on each pickup with trim pots and it’s promising as well.

I would like to experiment with spin a split on each humbucker in parallel when on together but possibly humcancelling like how I have the inner coils. But I’m not really able to picture how to diagram and wire this. Any suggestions? I’m thinking this would be a good way to fix the slight volume drop and with trim pots and perhaps a couple caps I can tune it to something decent.

I figure I have to treat one humbucker as reverse polarity and inverted wiring but the way they each start and finish, I can’t really diagram it.

[Clint 55]

Re: Idea on how to wire two spin a split pickups to cancel hum?

You said you already have it set up correctly for hum cancellation with inner coils. Just stick the duplex pot master spin a split in there and attach the series leads that you have going to ground for the full split. I recommend 50k for ideal taper. You also have to no load it.

[Bowtomecha]

Re: Idea on how to wire two spin a split pickups to cancel hum?

The thing is that the coils are Neck South/Neck North and Bridge South/Bridge North. The neck coils series junction when shunted to ground (either fully or partially) isolates the Neck North. Meanwhile the Bridge South to Bridge North series junction gets shunted to hot, bypassing the North coil to whatever degree. So it should be ideally mostly Neck North than Neck South but not fully, and mostly Bridge South than Bridge North but not fully, with the coils reverse in direction and polarity. The issue I see is with the Bridge North. The series junction on the bridge humbucker isn’t being shunted to ground. It’s being shunted to hot. I’m not sure that spin a split works this way. Not with a rheostat pot like I would use a trim pot as.

I guess what I’m saying is that I want to wire it so that whichever humbucker coils are hardwired to ground are shunted to ground variably at their series junctions, and the coil afterwards is sent to hot. But with the bridge humbucker having an inside out wiring and polarity for the inner coils, that hardwired to ground coil ends up (variably?) going to hot.

I’m simply trying to dump part of one coil to the 2nd coil of the neck humbucker, but have that 2nd coil on that humbucker being noise cancelling with the bridge humbucker setup (one coil partially dumped to the 2nd coil). So I probably need the Neck South variably shunted at the series with Neck North, and Bridge North variably shunted to ground at a series junction with Bridge South, the problem being that Bridge South->Bridge North currently and not Bridge North->Bridge South like this setup would need. Which must introduce a phase issue I think.

The Neck humbucker could use a rheostat between the series junction and the switch that shunts it to ground. But the bridge humbucker... it seems tricky. I’m actually hoping that I have all of this wrong and it’s a simple thing. But I don’t see anybody having done this before.

I’m not worried about switch limitations at this point. I have a 4 pole rotary to experiment with. If this could work, I wouldn’t mind not having a strictly inner coil configuration. I know spin a split works with two humbuckers, I’m just trying to make the last two coils in parallel humcancelling.

This is absolutely frying my brain, keeping up with winding direction, polarity, and starts and finishes.

[Bowtomecha]

Re: Idea on how to wire two spin a split pickups to cancel hum?

If I’m not ever using the inner coils in parallel split like I currently have it and just want neck humbucker/both humbuckers parallel and variably split and humbucking/bridge humbucker, then I could just connect the finishes on the bridge and ground the North start instead and make the South start hot and use a pot on the bridge serial junction to a switch that grounds it. Maybe?

[Bowtomecha]

Re: Idea on how to wire two spin a split pickups to cancel hum?

Maybe?

I think I have the leads wrong now.

No I think I’m right. These are Duncans by the way. With the bridge mag flipped.

[Clint 55]

Re: Idea on how to wire two spin a split pickups to cancel hum?

Ok I think all you do is leave the neck the same to split to the inner coil stock. Then you flip the mag in the bridge which you did and flip the hot and ground to get the polarity back in phase. Put your series junctions in each pup to your spin o splits and you're good. Again 50k works best for a spin o split. I have this in 1 of my guitars and it's not that hard to figure out. Only I'm using a master spin o split.

[Bowtomecha]

Re: Idea on how to wire two spin a split pickups to cancel hum?

I used a trim pot for my spin a split last year since I just want one setting without wiring a fixed resistor in and I don’t need to change it on the fly. But it would help to let me tweak it until I find a range that works with this. I found that under 10k worked well. In this case, I will use two, one for each pickup.

[Clint 55]

Re: Idea on how to wire two spin a split pickups to cancel hum?

Yeah that will be good having 1 split for each pickup. What are trim pots and what is the benefit to using them instead of using a regular variable sweep pot? Do you not mount them on the outside of your guitar or something?

[Bowtomecha]

Re: Idea on how to wire two spin a split pickups to cancel hum?

It’s just a potentiometer that you use a screwdriver to adjust. Most people I’ve seen that use spin a split end up liking just one particular value and then wire in a resistor closest to it. With a trim pot, I can adjust it inside the cavity and not have to bother. Prs uses 1k and 2k resistors for their splits so I can just use 2 trim pots of the same range and adjust them.

[Clint 55]

Re: Idea on how to wire two spin a split pickups to cancel hum?

Cool. I've found a 10k resistor to be about half way split. And I also liked 4 and 6k which sound pretty single coiley.