Spin-A-Split Using 2 separate SC's, Pot Value Question

[Drak]

So I have a new build finishing up soon and I want to use a S-A-S pot on it.
It's a Nashville style Tele.
I want to tie in the middle pickup to the bridge pickup so the middle pickup will be the one 'added in' the S-A-S.
And just use a standard 3-way Tele selector switch.
The pickups are all vintage winds, nothing over 6k on any of them.
So I was curious what pot value should I probably start out with.
If it was going to be a bone stock install, I would be using 250k's.
I'll probably wind up making a custom control plate with 3 knobs to handle volume, s-a-s, and tone.
Thanks guys.

 

[ItsaBass]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

The pot value isn't as important as it being linear taper.

The pot value does affect tone, but it need not be a particular value for all applications. But IMO you don't want your splitting to be audio taper, as it's too dramatic an effect up front.

I now wire my Jazz Basses with independent series wiring, which is basically a dual spin-a-split (two single coil pickups, wired in series, each with its own volume pot). The concept is the same as a spin-split: you are wiring the pot as a shunt, rather than as a controlled leak to ground like it usually is. I use 500K linear volume pots. If I was you, I would probably initially go for whichever pot value matched the rest of the pots in the guitar (probably 250K linear in your case), though 500K might be what you eventually settle on.

 

[beaubrummels]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

Doesn’t sound like spin a split. Sounds like just a simple volume pot for the middle to blend with the others instead of having it selected on the switch. A normal 250k linear would do.

I think the difference is you have to leave it ungrounded to not shut off the guitar when the middle is turned down? Either that or you’ll just get a darker sound if the middle is turned down at all as it will combine with the master volume to load the pickup. Someone else can check me on that. Last time I did a Tele blend I seem to recall that was my experience. I left the blend ungrounded and it worked perfect as expected.

 

[DavidRavenMoon]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

You’re talking about a volume control for the middle pickup. You can’t split single coils.


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[DavidRavenMoon]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

Doesn’t sound like spin a split. Sounds like just a simple volume pot for the middle to blend with the others instead of having it selected on the switch. A normal 250k linear would do.

I think the difference is you have to leave it ungrounded to not shut off the guitar when the middle is turned down? Either that or you’ll just get a darker sound if the middle is turned down at all as it will combine with the master volume to load the pickup. Someone else can check me on that. Last time I did a Tele blend I seem to recall that was my experience. I left the blend ungrounded and it worked perfect as expected.

Wire the control like a Jazz Bass. Series resistance will also dull the tone, as it increases the impedance.

If you unground the pot the pickup will still be heard a bit when it’s turned down


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[ItsaBass]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

He's talking about wiring B+M in series, with the pot to roll the middle pickup in or out. It's not the same as adding a middle pickup volume pot to a Strat. It is, in fact, just like a spin-a-split, with the only difference vs. a humbucker being the physical locations of the two coils. This eliminates the middle pickup solo, and just uses it to roll in varying degrees of extra juice from the bridge pickup.

Sounds like he already knows how to wire it, and is just curious what value pot to use.

 

[Drak]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

He's talking about wiring B+M in series, with the pot to roll the middle pickup in or out.
It's not the same as adding a middle pickup volume pot to a Strat.
It is, in fact, just like a spin-a-split, with the only difference vs. a humbucker being the physical locations of the two coils.
This eliminates the middle pickup solo, and just uses it to roll in varying degrees of extra juice from the bridge pickup.
Sounds like he already knows how to wire it, and is just curious what value pot to use.

Yes, this is Exactly what I meant.

 

[Bowtomecha]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

I thought that most spin a splits work best in the lower range like 25k and under.

 

[DavidRavenMoon]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

He's talking about wiring B+M in series, with the pot to roll the middle pickup in or out. It's not the same as adding a middle pickup volume pot to a Strat. It is, in fact, just like a spin-a-split, with the only difference vs. a humbucker being the physical locations of the two coils. This eliminates the middle pickup solo, and just uses it to roll in varying degrees of extra juice from the bridge pickup.

Sounds like he already knows how to wire it, and is just curious what value pot to use.

So it’s a blender. It’s still a volume control. Only it works on one pickup selection.


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[ItsaBass]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

So it’s a blender. It’s still a volume control. Only it works on one pickup selection.


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It's a series blender...AKA a spin-a-split. A typical "blender" control is a parallel blender. A series blender is not a typical volume control, as in a controlled leak to ground. it is a shunt, as in a controlled leak around the pickup. You are controlling how much of one coil's signal leaks around the second coil, and how much of it passes through the second coil.

 

[Drak]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

It's a series blender...AKA a spin-a-split.
A typical "blender" control is a parallel blender.
A series blender is not a typical volume control, as in a controlled leak to ground. it is a shunt, as in a controlled leak around the pickup.
You are controlling how much of one coil's signal leaks around the second coil, and how much of it passes through the second coil.

This is all quite correct and on the money.
But I thought there must be a logical cohesive answer to the pot value question by now.
I've read linear, I've read taper, I've read same value as you would normally use, I've read low numbers like 50K.
I figured there must be someone here who has done the footwork by now?

 

[Artie]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

You probably already know this, but be sure your bridge pup is the one on the "hot" side of the circuit. Like this:



Then, if it was me, I might temporarily, bring two wires out from under the control plate or pickguard attached at the series connection and ground, and then try several different pots. 250k, 500, and maybe 1M, to see which you like the reaction of best.

 

[blueman335]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

I use spin-a-split on neck HB's, and always use audio taper 500K's for them. I'd never consider using a darker pot for the neck slot. If I was using it on a bridge HB, I'd use a 250K, but nothing of a lower pot value. BTW, all of my PU's are HB's and P-90's, no Fender single coils.

 

[ItsaBass]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

This is all quite correct and on the money.
But I thought there must be a logical cohesive answer to the pot value question by now.
I've read linear, I've read taper, I've read same value as you would normally use, I've read low numbers like 50K.
I figured there must be someone here who has done the footwork by now?

All I know for sure from memory is that I used 500K for my Jazz Bass that I wired this way. There must be a diagram out there for guitar...and IMO, it must not be very different than what I used on the bass.

In this circuit, pot values don't have the same general effect on brightness that they do in a typical guitar control...because they are not leaking to ground. Therefore brightness isn't your concern in selecting the pot value. You just need the value that, when at maximum resistance, will close the road for the current from the bridge pickup, forcing it to go through the middle pickup coil instead of passing through the pot. I'd think that you want to err high, rather than low. Too low, and you can never have the full combination of both coils, because some juice will always be leaking through the pot, around the middle pickup. So I would grab 500K linear and 250K linear, and experiment.

 

[Drak]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

I'll just try a 250k audio for starters and see what happens then since I already have them here.
Thanks for the input!

 

[ItsaBass]

Re: Spin-A-Split Using 2 separate SC's, Pot Value Question

It'll work. Just realize that the higher the value, the more of a "complete" humbucker you will get when you are at maximum blend. It isn't that lower values won't work. It's just that they'll allow more leakage around the second coil, even when at maximum blend. More leakage around the second coil means less of the second coil in the mix. Since you probably don't really need the full use of both coils anyhow (two old-style Strat pickups in series is rather thick), it's probably not a big deal to go lower in value.