The Last Bass Outpost
Gear Discussion Forums => Bill's Shop: Projects, Mods & Repairs => Topic started by: ack1961 on September 12, 2014, 05:22:10 AM
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Hey guys,
I'm a real hack when it comes to working on basses, but I'm trying to fix a problem.
I bought a custom passive PJ set a few years back. They are totally anemic. They came without covers, paperwork, diagrams, etc.
The builder has never responded to my email questions, so I thought I'd get some help here.
I'm looking for help in two areas:
1. Resistance testing - I want to see if their worth putting in a project bass. I purchased a few neo magnets to help boost the signal, but want to compare the figures (with and without magnets), but I'm unsure of what the real useful test procedures are...
2. Wiring - The wiring pattern on this set looks different than any other passive P pickup I've come across.
On most Precision pickups I've worked with, the White lead (hot) comes off the pickup positioned closest to the neck - I call it "north" and it goes to the middle lug on the Neck Volume Pot. The black jumper wire goes to the pickup closer to the bridge and Black lead from that "south" pickup goes to the Neck Pot (ground).
Here's what mine looks like:
(http://i814.photobucket.com/albums/zz62/ack1961/Music/20140912_074630.jpg) (http://s814.photobucket.com/user/ack1961/media/Music/20140912_074630.jpg.html)
I'd just like to verify that I'm positioning (orienting) the split pickups correctly and testing them properly.
Any useful help would be greatly appreciated.
Thanks!
Steve
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Hey guys,
I'm looking for help in two areas:
1. Resistance testing - I want to see if their worth putting in a project bass. I purchased a few neo magnets to help boost the signal, but want to compare the figures (with and without magnets), but I'm unsure of what the real useful test procedures are...
2. Wiring - The wiring pattern on this set looks different than any other passive P pickup I've come across.
On most Precision pickups I've worked with, the White lead (hot) comes off the pickup positioned closest to the neck - I call it "north" and it goes to the middle lug on the Neck Volume Pot. The black jumper wire goes to the pickup closer to the bridge and Black lead from that "south" pickup goes to the Neck Pot (ground).
I'd just like to verify that I'm positioning (orienting) the split pickups correctly and testing them properly.
Any useful help would be greatly appreciated.
Thanks!
Steve
To compare the difference between alnico and alnico + neodymium I´d just trust my ears.
If the output is low, I´d rather go for a rewind than put on more magnets. Alnico5 is a strong magnet (if that is what you have) and personally some of the neos on the market causes too much string pull for my liking.
Testing the DCR is done with a ohmmeter, across the whole unit - 10.560 ohms is the P bass ´reference ´if I remember correct. Anything fairly close is good enough. Too high (near 20K) will, along with extra magnets, will be too dark or middish for most people, and perhaps too loud. If it is closer to 5K it might be a tad dull for a P. Each set should have about the same number of turns.
If this is a custom set, you must first verify what is start and finish of the winding. The standard way of winding a P is with the signal passing through the coils in opposing directions. And with opposing magnetic polarity.
I cant remember which unit is nearest the neck.. Hope this helped some.
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Thanks for the reply.
It's interesting, but I get no continuity when I touch my Ohmmeter leads to the copper strand solder joint on each side of the winding.
The same thing happens on the other split p. If I touch the Ohmmeter leads together, or each end of the wire going to the pot, the meter's alarm sounds, showing a close.
(http://i814.photobucket.com/albums/zz62/ack1961/Music/20140912_130425.jpg) (http://s814.photobucket.com/user/ack1961/media/Music/20140912_130425.jpg.html)
I would have thought that I could basically touch the meter's leads to 2 random spots on the bobbin, and get continuity.
Am I missing something?
Steve
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Test across the leads, black to white not at the coil. The coil wire is so thin, who knows what you"re actually touching with the meter probe. These are the only 2 wires coming out of the thing (the others just connect the 2 split halves of the P together). Which is (aka you use as) hot does not matter as long as you wire the P and J the same way (same maker shouled= same colour convention).
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Thanks, I first tested across the leads, but got nothing.
I then tested the lead wire itself (the bare lead end to the other end of the wire at the solder joint on the plate) and the lead is fine.
I just can't get any continuity from that point (towards the winding).
What I'm thinking (in order to isolate the fault) is that I should be able to put the meter probe on one end of the lead, then to anywhere on the spool, and get a reading.
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Thanks, I first tested across the leads, but got nothing.
I then tested the lead wire itself (the bare lead end to the other end of the wire at the solder joint on the plate) and the lead is fine.
I just can't get any continuity from that point (towards the winding).
What I'm thinking (in order to isolate the fault) is that I should be able to put the meter probe on one end of the lead, then to anywhere on the spool, and get a reading.
One coil is bad, the one that's giving a reading is good.
The spool as you call it, has INSULATED wiring. Breaking the insulation is the only way to get a reading and once you do that you've shorted the coil.
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One coil is bad, the one that's giving a reading is good.
That sounds accurate from the explanation offered. Should also explain low output.
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Thanks to all - I can't get a reading out of either coil. Oh well, they're trash - not worth the trouble.
I will NEVER buy another pickup set from a "custom builder" without doing my homework first.
Now to find another PJ set I can drop in...
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Thanks to all - I can't get a reading out of either coil. Oh well, they're trash - not worth the trouble.
I will NEVER buy another pickup set from a "custom builder" without doing my homework first.
Now to find another PJ set I can drop in...
Maybe maybe not.
Before I tossed them I'd try resoldering the coil to lead connection. It may just be a cold solder joint at the point where the coil is imbedded in the little pool of solder . . . actually I'd start on the the coil in the picture with the joint on the left in the photo it looks dull gray compared to the other side.
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Maybe maybe not.
Before I tossed them I'd try resoldering the coil to lead connection. It may just be a cold solder joint at the point where the coil is imbedded in the little pool of solder . . . actually I'd start on the the coil in the picture with the joint on the left in the photo it looks dull gray compared to the other side.
Will do - I appreciate the response.
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Will do - I appreciate the response.
You should be able to strip the wire and test, i agree.
If you have no luck, I do rewind pickups for $60 if you pay for shipping to Norway.
There are probably other here on the LBO with a winder who probably lives closer to you too :)
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I'll trade you a working SX P bass pickup for your dead one. PM me if you're interested.
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Give me five dollars and here's your ten back...?
You gotta love these swampers... :)
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Just happen to know a pickup winder I trust, Kenny. ;)
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Just happen to know a pickup winder I trust, Kenny. ;)