Polarity question

Bass-desires · #1 06-25-2009, 09:24 PM

Hey guys, I got a Epi Rockbass for cheap and wanted to fix it up. I got most of it put together but I was not getting the humbucking when the pups were equal. After scratching my head I checked the polarity and found both pups show a south pole polarity. (The north points to them both)

Is this something I can affect with re-wiring the pups? Or do I need a new pup?

Thanks guys

walterw · #2 06-25-2009, 11:21 PM

you could bust the ceramic magnets off the back of one pickup, spin them on their axes 180 degrees, glue them back on, then reverse the wires of that pickup. that's a lot of work for a basically disposable pickup, though.

Mikey3 · #3 06-26-2009, 05:59 AM

I had this problem on a p bass, where I wasnt getting the bucker sound at all. Ended up both coils were the same polarity. I took two strong magnets, made a rig, and ran the pickup through it a couple times to change its polarity. Worked like a charm, and the bass sounds amazing.

A member (Bygde) showed me this on youtube, when I ran into a similar problem
http://www.youtube.com/watch?v=5Zk6Kbg6p78

Bass-desires · #4 06-26-2009, 06:36 AM

Either that or I could just spend $15 and get a replacement pup thats an equivalent....or wait on the bass-lines set I'm bidding on...heheh..Thanks for the help and info!

Stealth · #5 06-26-2009, 08:14 AM

Quote:

Originally Posted by Mikey3

I had this problem on a p bass, where I wasnt getting the bucker sound at all. Ended up both coils were the same polarity. I took two strong magnets, made a rig, and ran the pickup through it a couple times to change its polarity. Worked like a charm, and the bass sounds amazing

Do you recall what you used as "flipping" magnets? Two large, high-grade neodymiums?

Mikey3 · #6 06-26-2009, 02:41 PM

You can get some neo magnets from stew mac, and as i recall they are not expensive. However, I went to a local hardware store and bought two strong magnets that welders would use. I think they could carry 50lbs each. They are big, but again if serious about changing I would go to stewmac.com and get some of their magnets that are used for this specific purpose.

DanRJBrasil · #7 06-26-2009, 02:50 PM

old Hard disks usually has neo magnets inside , if you have some broken ones maybe its a good use for it , I don't know if it is enough though

Bass-desires · #8 06-30-2009, 07:50 AM

Well, after looking around El Paso, and not finding any neodymium magnets readily available I am going to drop a Ibanez jazz bridge pup in, if the dimensions will work. I have found the regular ceramic magnets but anyone know where in El Paso I can find the neodymium?

I'll keep you guys posted. Thanks!

Bass-desires · #9 07-02-2009, 06:05 AM

Hey Guys, just an update, after combing the city of El Paso and not really finding neodymium magnets I chose to rewire and drop and Ibanez dxj J pup in. I also put in a push pull for series parallel switch and I like it.

Question though: When checking to make sure the new pup had correct polarity I noticed it has a north pole and south pole on the left and right of the pup. I'd never seen that before. Does that mean its a noise cancelling pup? To get both neck and bridge to hum-buck I have to have the bridge (The new one) full up, and the neck, just about at 8.

Can anyone give me some info on this?

Thanks

Stealth · #10 07-02-2009, 07:11 AM

In all likelihood, if one end has an N pole, and the other S, it's hum-canceling. You can verify it by just removing the pickup cover and counting the coils - one coil and the pickup's a screwball (but a working one), two coils and it's humbucking.

Bass-desires · #11 07-02-2009, 10:06 AM

Ok well, I feel silly, but after I went ahead and put in the Ibanez DXJ pup, I was re-reading the list of posts and saw the fellow who suggested pulling the pup and switching the magnets. Well, I just did it and wish I had kept the orginal pup in because I like how it sounds clean but full on the low end (not fat). The new pup has that humbucker sound to it...its ok.

I'll switch it out later if I have time. Now another question is:

There are two magnets on the original pup, if one was flipped and the other one wasn't, would that create a humbucking pup? Just wondering even though I don't like the sound, it would be good in my PJ bass.
Thanks!

Stealth · #12 07-02-2009, 10:46 AM

Even if the magnets are side-by-side (that is, one magnet covers the EA polepieces and the other covers the DG polepieces), flipping the magnets isn't enough. The coil that's around the EA polepieces should be wound in the opposite direction of the DG coil.

In short: for humcanceling, if you look at the pickup from above, one half should have its north facing you and be wound in one direction (say, clockwise), the other half should have its south facing you and be wound in the other direction (say, counterclockwise).

N+CW and S+CCW = humcanceling
N+CCW and S+CW = humcanceling
anything else = not so humcanceling or not humcanceling a at all.

Dave Kerr · #13 07-02-2009, 01:08 PM

Quote:

Originally Posted by Stealth

Even if the magnets are side-by-side (that is, one magnet covers the EA polepieces and the other covers the DG polepieces), flipping the magnets isn't enough. The coil that's around the EA polepieces should be wound in the opposite direction of the DG coil.

In short: for humcanceling, if you look at the pickup from above, one half should have its north facing you and be wound in one direction (say, clockwise), the other half should have its south facing you and be wound in the other direction (say, counterclockwise).

N+CW and S+CCW = humcanceling
N+CCW and S+CW = humcanceling
anything else = not so humcanceling or not humcanceling a at all.

You don't have to rewind the coil after flipping the magnets, just swap the hot/ground leads when hooking it up to the guitar. The only thing to look for is whether there's any metal parts of the pickup (baseplate, metal pole pieces, etc) that are connected to that same pickup lead - you'll want to run a separate ground to them.

Bass-desires, how are those 2 magnets configured - one on each side of the pole pieces, like a P90 guitar pickup?
http://www.harmony-central.com/Produ.../000013141.jpg
If so, flip them both - you'll want either each N pole facing the poles, or each S pole. You'll have a very weak pickup otherwise.

Regarding reversing the polarity of a magnet using large neos, that'll work on alnico mags, but not ceramic.

Bass-desires · #14 07-02-2009, 04:39 PM

Hey Guys, thanks for all the advice. The magnets are side by side covering the entire bottom of the pup as you can see on the pics.

So I can flip the magnets and flip the wires and have the pup at the opposite polarity? Assuming there are no other additional metal pieces attached. At this point in the game, is there anything I can do to the pup other than flipping it and putting it back together?