Strange Pickup Problem.

[Mr.T]

I have just finished building a natural ash bodied PJ.

It has a Seymour Duncan Quarter Pounder P pickup and a Wizard '84 J pickup, with stacked volume pots.

Anyway,
I also have a P bass that has a Wizard Thumper, so I thought I'd swap the P pickups.
Quarter Pounder in the Precision and Thumper/'84 in the PJ.

I did the transplant, plugged in the PJ, and found that with both pickups on 'full' the output dropped considerably.
No problem, I thought, reverse the wiring on the J pickup and all will be fine.
(I had to do this when I fitted a pair of '84s to my Jazz).

But,
After reversing the Jazz pickup, I noticed that the output drop was still there... but only on the D and G strings.

Huh?,
So I reversed the Jazz pickup again, and sure enough the output drop was only on the E and A strings.

After much headscratching, I put the Quarter Pounder back in the PJ and the Thumper back in the Precision.... and they all work fine.

I am stumped.
Probably missing something obvious!

Any ideas?

[henry norton]

Sounds like your P pickup has been wired 'out of phase' or more like 'out of polarity and maybe upside down' with itself. Does the P hum significantly (like a single coil)? This way, either coil in the p will be out of phase with the J.

Do you get what I'm getting at??????

[henry norton]

What I mean is, a P pup is essentially 2 single coils with opposite polarities & windings to cancel hum. Thing is, if you wire in one of the coils the other way around it won't affect the output of the pup because the coils are working on seperate sets of strings (e&a & d&g). What it will do is monkey around with your sound if another pickup is brought into the mix 'cos your single coil J is bound to be out of phase with one or 'tother of the P coils. Just try swapping the polarity of one of your P coils should sort it (and you might find you get less hum too)

[Mr.T]

Hi,

That makes sense!

So as I change the polarity of the Jazz pickup, I cancel out one or other of the Precision pickups.

The Precision pickup (Wizard Thumper) does seem to work fine on its own.

Is there a way I can test this, or is it just a case of switching the connections on the Thumper... and seeing what happens?

[henry norton]

[quote name='Mr.T' post='619357' date='Oct 7 2009, 11:08 AM']Hi,

That makes sense!

So as I change the polarity of the Jazz pickup, I cancel out one or other of the Precision pickups.

The Precision pickup (Wizard Thumper) does seem to work fine on its own.

Is there a way I can test this, or is it just a case of switching the connections on the Thumper... and seeing what happens?[/quote]
You kind of have performed the test already - switch the connections for the thumper then check against the Jazz - either you'll be weak across all strings (in which case reverse the J again) or it'll be fine across all strings.

Nice chop by the way - is that a rigid frame?

[Mr.T]

Thanks for the tips, I'll give that a go!

The frame is a modified Santee... stretched and lowered.
The rear suspension is like a Harley Softail... the shocks are hidden under the rear arm.
My rigid riding days are over, paticularly with the state of some of the roads here in the west country.

[henry norton]

[quote name='Mr.T' post='620275' date='Oct 8 2009, 10:31 AM']My rigid riding days are over, paticularly with the state of some of the roads here in the west country. [/quote]

If it's any consolation I'm starting to feel the same way about hi-comp pistons and kick starts. Good luck with the pup, let us know how it goes

[Mr.T]

Finally had a bit of spare time to switch the connections of the P p/up.

All working how it should.

Thanks for the tip!