Modifying a split coil arrangement

dern

Hello, I posted this question in a thread in the guitar bit on a thread where I was asking for advice about which pickups to use for my LP but I suspect that it was veering off from the original subject so I thought you guys might be able to offer me some advice...

I have a les paul studio (2012) with the following setup...

...sadly all this is on a PCB so will need a bit of thought before applying the soldering iron but everything is doable until it's screwed up

Anyway the question is... currently the coil split cuts out one coil on each humbucker when the appropriate push/pull volume knob is pulled leaving a single coil configuration. It's been suggested to me that I can modify this in such a way so that instead of losing one coil I can still have it but at a reduced level by adding a resistor... I understand that this is how PRS do coil splitting. Am I right that to achieve this I need to wire in a resistor in series with the 0.033uf caps that go to ground? If I'm not could you advise how the above wiring diagram could be modified to achieve this and then I can work out how I can modify the PCB.

Thanks very much and apologies if I'm miles wide of the mark in the above.

Cheers,

Mark

GuitarMonkey

Just replace the .033 caps with the resistors.

dern

Ok, thanks. What do the caps do in that circuit? I did notice that similar coil split circuits don't have them.

Thanks,

Mark

Fuzzdog

dern said:

Ok, thanks. What do the caps do in that circuit? I did notice that similar coil split circuits don't have them.

Thanks,

Mark

The caps are just another way of trying to improve the split tones - the caps only let a restricted range of frequencies though to ground rather than the whole lot, so you end up with some remaining frequencies from the usually ignored coil rather than a full split.  Can work rather well if the values are just right, but the resistor method is usually easier to dial in perfectly.

If it's on a PCB and you want to keep it that way, I'd replace the caps with some little trimmer pots personally, that way you can get things perfect.

ICBM

The caps are supposed to retain the hum-cancellation, by only allowing through the frequencies above 50/60Hz. The values aren't large enough to properly do that though, and it can also sound a bit odd.

I would replace them with the resistors, either using trimmers or the PRS values if you don't want to mess about - 1.1K (1K is probably close enough) for the neck pickup, and 2.2K for the bridge.

dern

I'll be retaining the PCB for now so the trimmer pots are a great idea, I'll do that, thanks.

Regards,

Mark