Help! Coil tap wiring....

Parker

Bought an Epi SG Pro. The wiring had been reversed (treble in bass position and visa verse). Decided to completely rewire properly. I’ve done that and followed a Seymour Duncan diagram. It now works as it should (eg SG Std  wiring), but the coil taps don’t work!? Totally confused why that would be the case.

NB - The taps on each volume. 

Eek - help!

TTony

 The colour-coding on the SD wiring diagrams assume that you're using SD pickups.  Different brands use different coloured wiring, and - just to make it even more fun - different purposes for same colour wirings.

If you've got a multimeter to hand, you should be able to test the function of the wires in the Epi's p'ups to work out what each is doing, and then translate that onto the SD diagrams ...

[edit] I *believe* that Epi p'ups use the Gibson colour coding - as below.

TTony

ICBM

You mean coil splits . [/pedant]

If Funkfingers is correct and you've used Duncan wiring colours with Gibson-wired pickups, what you've got by connecting the red and white wires together is shorting the north coil completely. The sound you're getting in the 'humbucker' setting will be just the south coil, and all the coil split switch will do is connect the shorted north coil to ground, or not, so it will make little or no difference to the sound.

By an odd coincidence, this may be very interesting to @Amigo since we have been discussing exactly whether this would make any difference or not in another thread... it won't fix your problem (yet) but it would be interesting to know whether you can hear any difference at all between the sounds - try it on a clean sound with the amp up fairly loud and see if you hear any change when you operate the switch. (I know this isn't quite what we're trying to test there either, but it might give a clue.)

Funkfingers

Parker said:

Bought an Epi SG Pro. The wiring had been reversed (treble in bass position and visa verse). 

This is almost certainly evidence of a bungled selector switch replacement job by a previous owner. Your original problem could have been solved by swapping the two signal input conductor wires at the selector switch.

If the original selector switch is/was one of the enclosed in a metal box types, something as simple as loosening the threaded fastener and allowing the switch to rotate through one hundred and eighty degrees could produce the "reverse" wiring illusion.

Given the natural tones of an SG with P.A.F.-ish humbuckers, coil splits should be unnecessary. 

ICBM said:

If Funkfingers is correct

Whaddya mean, if?

Parker

Thanks everyone. Helpful as ever (and feel stupid that I forgot the #1 rule with pick up wiring. I got there in the end, but it wasn’t easy. There was only limited wire left which made it a pig to cleanly solder. 

I did test it for you guys before I rectified it. There was perhaps a very very negligible difference, but it was so subtle, you wouldn’t notice. 

ICBM

Parker said:

I did test it for you guys before I rectified it. There was perhaps a very very negligible difference, but it was so subtle, you wouldn’t notice. 

Thanks - that’s what I expected. That’s ‘stage 1’ of the test - you’ve eliminated the capacitance of the second coil being next to the first one as a possible cause of any difference. Stage 2 is to find out whether that coil being shorted or not makes a difference.

Parker said:

feel stupid that I forgot the #1 rule with pick up wiring. I got there in the end

If only the different pickup manufacturers hadn’t thought it was a great idea to explore all 24 possible variations of four colour codes, it would be much less of a faff...