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Unsuccessful JTV pickup swap :(
by ryancola on 2013-02-17 03:22:48

So the bridge pickup in my JTV-89 has been microphonic for some time now, maybe even since I very first got it. When I first noticed it I didn't even know what microphonic meant for a pickup (thought it was just a tube thing), and I thought it had something to do with pickup height or my amp settings. I lived with it for a while until it started getting worse, and then I did a little research online and found out how to test to see if it was microphonic (and it was, of course). So, I thought about trying to repot the pickup, but then I decided I'd take the opportunity to just put a new one in. I decided on a Suhr Aldrich, and when I got it I opened up the JTV and took the bridge pup out without any hassle. I made a drawing of the wiring before I took the pickup out, and then I went online to find a diagram for the Suhr pickup, matched up the colors, and installed it. It didn't work right. For one thing, the coil tap and humbucking positions were swapped, and overall the output was very weak (and this is high-output pickup) and noisy. I figured I'd try again, this time switching the middle two wires to correct my first mistake. I tried to be a little more careful with the soldering, and I even trimmed the leads back a little so there wouldn't be as much bare wire exposed. Once again, not working right. The pickups are still far too noisy, and there is no apparent difference between the 1 and 2 positions on the switch. At this point I just closed it up and put it away. I'm probably going to see if I can send it back to Line 6 for repair, but I wanted to check here first and see if anyone has done the swap and ran into similar problems (and hopefully fixed them!). I'm all ears.

Oh, and in case anyone thinks he/she can help, here is what I did for the wiring: on the Suhr, the color code is supposedly the same as Seymour Duncan, so black = north start, white = north finish, red = south finish, green = ground/south start. I put heat shrink tubing on the bare shielding wire and soldered it to the same spot as the shield wire in the factory pup. Then I found the wiring diagram on the Line 6 site and assumed the colors shown were in order (north at top, south at bottom), so that's how I matched them up.



Re: Unsuccessful JTV pickup swap :(
by Nipp on 2013-02-17 03:43:41

You cannot go by colors - they are very different on different brands.

You must figure out what is each coil to start with on the original pickup - use a multimeter ohm measurement.

And you can see that no wires are broken as well. Wire for coil are really, really thin, so they break easily.

Does this fit the wiring you did now - what belongs to each coil on the new pickup?

You could also try rewax you original pickup and put it back. It might fix microphonic and all of it.



Re: Unsuccessful JTV pickup swap :(
by ryancola on 2013-02-17 05:03:07

I didn't use the same colors; I used wiring diagrams for each of the pickups to match up which leads were which. Unfortunately I don't have a multimeter and I wouldn't know what to do with it if I did. I could try repotting the pickup I suppose, might do that before I try sending it in for repair. Thanks for the tip.



Re: Unsuccessful JTV pickup swap :(
by Nipp on 2013-02-17 05:39:22

If you are to fiddle with guitar, if you excuse the wording, then a digital multimeter is a really good investment, and it's cheap - around $30-$50 or so or even cheaper.Or just borrow one from a friend.

Just put one prope on each cable, metering to ohm(20k or more scale) and you will see where you have contact or not.

Full high output humbucker is maybe 13-15kohm, and one coil half of that around 7-8k.

If having two cords that connect(around 8k, or less than infinite ohms) these are same coil.

Knowing that, now it's only about getting phase right. It's easier with a analog meter, but could be done with digital too.

Basically you set it to measure volts, connect as before, and hitting pickup lightly with something magnetic - like a screw driver - you can see if voltage rise or not - when pushing screw driver towards magnetic poles. Switch direction and pull screw driver if not voltage is shown. You should get a reaction in one direction at least - positive or negative. Doing that test on original and new pickup you can get it right, matching them.

For phase test, you might need to set right high sensitivity to mV, millivolts or so.




The information above may not be current, and you should direct questions to the current forum or review the manual.