Bridge Pickup Problem...

[TemjinStrife]

I just finished wiring up and setting up a Dean Evo 7 that I picked up off of ebay completely stripped of all parts except for ferrules, the bridge bushings and bridge ground wire.

After installing a pair of Duncan Design 7-string pickups (also off of ebay) I've run into a bit of an issue that I'm not sure what to do about short of rewiring the whole thing... based on the information below does anyone have any idea?

The setup is as follows:

2 4-wire humbuckers (Seymour Duncan wiring colors) into a 3-way LP-style switch and a single volume/tone. The volume knob pulls to split both pickups.

Seymour Duncan Wiring Diagram

The symptoms:

Neck pickup works fine, splits fine. Tone and volume work properly.

Bridge pickup has an extremely low output and very bright percussive sound, which is odd considering it's a JB clone. Splitting this pickup only lowers the output even more. The tone knob seems to act as a volume knob for this pickup only.

Any ideas? Would any other information be useful to you electronics gurus out there to help?

[digi2t]

Bridge pickup has an extremely low output and very bright percussive sound, which is odd considering it's a JB clone.

I'm confused. Is it an actual Duncan PU or a clone? You mentioned before that you installed a Duncan, then you state it's a clone. If it is a clone, are you sure that the wires are color coded the same as a real Duncan? I mean, you may have the same colors in front of you, but they may represent different leads. Might be your problem.

Cheers

[TemjinStrife]

Bridge pickup has an extremely low output and very bright percussive sound, which is odd considering it's a JB clone.

I'm confused. Is it an actual Duncan PU or a clone? You mentioned before that you installed a Duncan, then you state it's a clone. If it is a clone, are you sure that the wires are color coded the same as a real Duncan? I mean, you may have the same colors in front of you, but they may represent different leads. Might be your problem.

Cheers

It's a Duncan Designed JB-7. Basically, a Korean or Chinese or something-made pickup that's based on the JB design and uses the same wiring scheme, just is made elsewhere (and thus cheaper) than the USA-made Seymour Duncan range. The neck pickup is a matching Duncan Designed Jazz that works and sounds fine and was soldered in the same way with regards to the leads.

Thanks for the response.

[SwedishLuthier]

Sound a bit strange all this. My first thought was that you got the two coils out of phase, but then you should actually get a louder sound when splitting the coils.

You can try this. De-solder the pickup from the rest of the electronics and get it directly to the output jack, no volume no tone no nothing. How does that sound? If you still have bad sound the problem is in the pickup. But if you have a good sound...well start looking trough the rest of the wiring.

If the bad sound continues, then try to measure the DC resistance of the coil(s). It should be at least 16 Kohms when in series as for the original 6-string JBs. If they are way off you probably have a partial short out. Measure each of the coils by it self. They should be something like 8 Kohms. That is also a way to check that the correct colours were used for the leads. I think that you should have the 8 Kohms between black and white, and between red and green, but I’m only like 98% sure here. You can also check for DC resistance between the two coils. You should of cause have infinite resistance between the leads of one coil and the leads of the other coil. If you have anything that differs a lot from those numbers mentioned you have a faulty pickup.

[TemjinStrife]

Pickup seems fine... around 17.2k of resistance, which is close to my 6-string JB. I'm now checking for bad solder joints and/or shorts.

[TemjinStrife]

Alright, figured it out.

The sleeving had been accidentally soldered to the black output wire of the humbucker... it's impressive that we got any output at all. Now that that's fixed, the thing works and sounds great!

Thanks for your help everyone!