Pickup polarity angst!

lowendgenerator · #1 08-05-2011, 08:26 PM

I've got this Jazz bass, see? It's got a set of Basslines in it, and something is funky. When I have both pickups on full, I lose a lot of bottom end and some overall volume. When I roll either pickup back past 8, the tone springs to life and I have gobs of bottom end. I'm not having any humbucking issues, so I'm going to go out on a limb and assume they are installed correctly.

Is it possible that I have the same polarity in both pickups? The bass and the pickups came to me used, so a warranty is out of the question. How much should I be prepared to spend to get this fixed? From what I've seen on YouTube, it's a fairly simple fix. Remove pickup, swipe the magnets past a stronger magnet to change the polarity, and re-install.

Stealth · #2 08-06-2011, 02:20 AM

It's not necessarily the magnets, it could be as simple as the pickup wires being out-of-polarity - in other words, try just swapping the leads of one of the pickups. Unsolder the pickup ground from the pot it's attached to, unsolder the pickup hot lead from the pot it's attached to, and then solder them backwards.

walterw · #3 08-06-2011, 12:16 PM

Test that magnet polarity first before trying to change it.

Just get a little magnet or even a compass, and see if both pickups attract or repel the same.

lowendgenerator · #4 08-06-2011, 12:23 PM

Quote:

Originally Posted by walterw

Test that magnet polarity first before trying to change it.

Just get a little magnet or even a compass, and see if both pickups attract or repel the same.

Just tried that, they are in fact opposite polarity. Maybe I should try swapping the leads on one of the pickups as suggested.

4Mal · #5 08-06-2011, 12:25 PM

Really? Ya think ?

Dood, just get the iron hot

lowendgenerator · #6 08-06-2011, 12:30 PM

Quote:

Originally Posted by 4Mal

Really? Ya think ?

Dood, just get the iron hot

Thanks, I'll try that! KTHXBAI!

walterw · #7 08-06-2011, 08:47 PM

hmm, you wouldn't get hum-canceling with opposite-polarity coils and one wired backwards.

yes, swap the wires on one of them of course.

here's the key to that trick: turn up both pickups, then touch the magnet polepieces of each one. if one of the two is really noisy when touched, reverse the wires of that pickup.

Jay2U · #8 08-07-2011, 09:27 AM

Beware! Some pick-ups have the ground wire attached to the magnets to reduce hum. If you swap wires in that case, the output signal may start to hum as soon as you touch the pick-up, or even come near to it. It doesn't damage anything, as long as you keep the volume down. So you could just try and see what happens.

walterw · #9 08-07-2011, 12:21 PM

true, but it won't damage anything regardless. it'll just be noisy.

lowendgenerator · #10 08-07-2011, 04:25 PM

Here's a shot of the control cavity. This isn't wired at all like the Seymour Duncan diagram. What a pain in the ass. Where do I begin?

walterw · #11 08-07-2011, 07:08 PM

the hell? you have one cloth wire coming from each pickup hole, and not even the same color. also, if these are a matched set of whatever, the white wire should not be going to ground.

what do the pickups themselves look like?

lowendgenerator · #12 08-07-2011, 07:34 PM

They're supposedly "Basslines", but the poles are a bit recessed in to the covers. Dinner is done, I'm gonna throw it on the counter and pull one out. I think I'm about to have words with the seller.

BlueTalon · #13 08-07-2011, 09:18 PM

I'll be interested to know about the outcome.

Jay2U · #14 08-08-2011, 12:11 PM

It looks quite messy inside. That reminds me of my Ibanez GSR200EX. I bought new, but spent some hours to rewire the grounding of the bridge and to re-solder the wires to the controls. Those wires came almost off. I downloaded a diagram in which the colours of the wires don't match the actual colours by far.

lowendgenerator · #15 08-14-2011, 09:56 PM

I opened it up, and quickly decided to put it back together. I have been known to murder electronics, and I am way out of my league on this one. I'm taking it to a local guru this week and having a different set of pickups put in entirely. The Basslines are gonna go in my 2000 MIM Jazz Deluxe. It's currently got Suhr designed pickups in it, and I hate them.

Anyway, to those waiting for an answer, be patient. I won't forget to resolve this thread with exactly what the HELL happened here lol.

walterw · #16 08-14-2011, 10:20 PM

assuming they really are duncan basslines and not something else shoved under duncan covers! the lack of the second cloth wire from each pickup makes me suspicious.

i usually see the cloth wire on duncans that are vintage repros and do not have logos on the covers, and i see the logos on more "modern" duncans with hum-canceling or overwinding or whatever, and these usually have straight-up plastic insulation on the wires.

SGD Lutherie · #17 08-15-2011, 10:17 AM

I don't think these are Duncans. I've never seen a red wire on passive Duncans.

Either way, just swap the hot and ground on one of the pickups.

lowendgenerator · #18 08-15-2011, 10:27 AM

I'll pull one of the pickups back out today and take some photos. These had better be duncans, or I was the victim of some false advertising. That's pretty much the whole reason I bought the bass. Ugh.

lowendgenerator · #19 09-01-2011, 09:32 PM

16 days later update....

I finally got up the nerve to take another peek inside the bass. The wires coming from the pickup bobbins are obviously not original, as the soldering job sucked. Each bobbin had one cloth wire and one nylon wire coming into the cavity. Why they were soldered the way they were above is beyond me. All those extra black wires soldered to the back of the bridge volume pot are the various grounds. Not sure how well that's working, as this bass has the WORST case of hum.

SO I fired up the iron, and rewired it per Duncan spec sheet above. Guess what. It sounds the same. Same thin, hollow tone with both volumes maxed, gets fuller on the bottom end as soon as you roll either back. I'm gonna open her up one more time and swap the leads on the neck pickup, even though this goes against the wiring diagram, my half-assed diagnosis of the pickup polarities, and my Polish intuition. If this doesn't work, I have no choice but to burn the bass.

lowendgenerator · #20 09-01-2011, 10:22 PM

Quote:

Originally Posted by SGD Lutherie

I don't think these are Duncans. I've never seen a red wire on passive Duncans.

Either way, just swap the hot and ground on one of the pickups.

As usual...Dave was right. Flipped the leads, and all is as it should be...Even though it's opposite to what the Duncan diagram shows.

Yay!