Duncan P Pup Wiring Help - Diagram attached...

wateroftyne · #1 02-20-2009, 03:35 PM

Hi all

I picked up a used Duncan Lightnin' Rod a few weeks ago... it's supposed to be vintage-ish but a little more accurate.

I dropped it into my P, and while it's amazingly silent as far as signal>noise goes, the output is a little lower than my passive pups and it doesn't pack much oomph.

It may be that it just isn't for me, but I thought I'd check the wiring just in case.

Turns out it's quite different to SD's diagram. Before I give it to someone to re-wire (I'm lethal with a soldering iron), I'd be grateful if someone could have a look and tell me wether it's 'wrong' or just a different way to do to the same thing.

Also, apart from the wiring, the SD diagram shows a .05 cap. Mine is a yellow thing marked '.1K'. Assuming this is wrong, what difference would it make to it all?

The wire connecting the base of the two pots has me especially puzzled!

Here is what Duncan recommend:

..and here is how the previous owner has it wired up:

So... the same, but different - or totally wrong?

Thanks in advance!

60bass · #2 02-20-2009, 03:53 PM

Quote:

Originally Posted by wateroftyne

Hi all

I picked up a used Duncan Lightnin' Rod a few weeks ago... it's supposed to be vintage-ish but a little more accurate.

I dropped it into my P, and while it's amazingly silent as far as signal>noise goes, the output is a little lower than my passive pups and it doesn't pack much oomph.

It may be that it just isn't for me, but I thought I'd check the wiring just in case.

Turns out it's quite different to SD's diagram. Before I give it to someone to re-wire (I'm lethal with a soldering iron), I'd be grateful if someone could have a look and tell me wether it's 'wrong' or just a different way to do to the same thing.

Also, apart from the wiring, the SD diagram shows a .05 cap. Mine is a yellow thing marked '.1K'. Assuming this is wrong, what difference would it make to it all?

The wire connecting the base of the two pots has me especially puzzled!

Here is what Duncan recommend:

..and here is how the previous owner has it wired up:

So... the same, but different - or totally wrong?

Thanks in advance!

The same but different, true. He has the ring and tip reversed on the input jack and the tone pot is basically the same. He's still using two lugs. The extra wire between the two pots is a ground wire connecting the two pots together. Many Fender basses and guitars are wired this way. Maybe he was having ground issues and tried to add the extra wire. If so, he actually made it worse by possibly creating a ground loop. Fender Strats are notorious for ground loops when wired that way.

The .05 cap is what the current Fenders use. I would start there and see if you like the tone.

When in doubt, wire it like the manufacturer suggests.

wateroftyne · #3 02-20-2009, 04:07 PM

Thanks, 60bass!

Hmm.. noise isn't a problem - it just sounds a bit 'polite'. So.. it might not just be for me. Maybe I should just try another pup...

Thanks again.

wateroftyne · #4 02-21-2009, 05:00 AM

Right... I've rewired it so it is 'correct' - quite an undertaking for me!

Anyway, it working... difficult to tell if it sounds any different. I'll know more after the next gig.

Am I right in thinking the cap value is irrelevant as long as I keep the tone wide open?

slyjoe · #5 02-21-2009, 06:26 AM

No - the tone cap is still in parallel with the circuit when the pot is wide open. But that's how most passive basses are anyway.

60bass · #6 02-26-2009, 09:19 AM

Quote:

Originally Posted by wateroftyne

Right... I've rewired it so it is 'correct' - quite an undertaking for me!

Anyway, it working... difficult to tell if it sounds any different. I'll know more after the next gig.

Am I right in thinking the cap value is irrelevant as long as I keep the tone wide open?

The cap will always be "in circuit" regardless of where the tone control is set. If you truly want "no cap" in curcuit, get a Fender "no load" pot. It has a small click at the end of it's travel which removes the cap from the circuit and allows the signal to pass straight through.

Keep Low

JTE · #7 02-26-2009, 10:15 AM

The previous owner has the wiper from the volume pot going to the ring of the stereo jack. That's not going to hit the tip of your cord when you plug in, but ground against the sleeve of the mono plug. That should be a real problem.

As 60Bass says, the wire connecting the two pot bodies is a solid ground. Duncan's wiring diagram seems to assume that there's foil or metal in the pickguard to connect the two pots' bodies together for the ground connection. It's common of Fender stuff, but not reliable so adding that ground wire isn't part of the problem. And the tone control wiring is just reversed, but electrically the same. The cap shunts highs to ground and they've only reversed where the wiper and the cap hit the circuit.

But correcting the wiring at the 1/4" jack is pretty important.

jte

JTE · #8 02-26-2009, 11:17 AM

Wait a second! It's WOT from FDP!??!?!? How cool is that? I'm John Evans from there!

I'm now "persona non grata" in Chris' living room- I guess I'm left of Al Haig and that got me banned. How is Mrs. WOT and the young un?

jte

wateroftyne · #9 02-26-2009, 03:35 PM

Hey John... how are you? Great to hear from you!

I'm rarely at the FDP these days for the reasons you suggest. Shame, but that's a whole other thread!

Mrs WoT and WoT Junior are both tip-top. How's yourself?

Thanks for the wiring help, by the way... to you and all the others.