Ganging two single coil pups to make one humbucker???

[vindibona1]

I've got a Squier Jaguar VM ACTIVE single humbucker bass that's been giving me a nasty single-coil type hum. The local technician checked it out and said that when he hooked up a Bartolini pickup to it it had no hum and must be the pickup. I ordered a cheap soap-bar (supposed humbucker) pickup off of ebay but when I got it hooked up it hummed too. I'm not sure what to believe. Let's assume the tech is right and I just have two defective humbuckers for now.

In the bin I have two Duncan Design single coils (from jazz bass) that are doing nothing. If in fact the pickup was the problem I was wondering if I couldn't gang the two single coils together to create a single humbucker? Obviously if it worked I'd have to make some minor body modifications, but if it did work I think it could work well. Would it?

If so, how would I wire the pickups to act as a single humbucker that gets wired to a single hot terminal and single common terminal on the circuit board? I know that 4 wire humbuckers have north/south wires, etc. but am a little confused by that. Any help that you could provide would be greatly appreciated.

TIA

 

[202dy]

That's a lot of work to get rid of some hum.

Before deciding what to do, it would make more sense to figure out what is causing the hum. Two poorly matched coils will create hum in a humbucker. Sloppy shielding will allow hum in the circuit.

For the first you must measure the resistance of the individual coils. Then rewind the coil of your choice. Or partially unwind one of the coils until the resistances match. That's a pretty tall task for most people, to say nothing of building or buying a coil winder. For the second, the remedy is to a good job of shielding the guitar. That means using shielding tape (copper foil) or shielding paint and making sure the ground circuit has no loops. The second recommendation is usually the way to go.

To answer your question, the two single coil pickups should be wired in series, out of phase to create the "giant" humbucker.

 

[ctmullins]

To answer your question, the two single coil pickups should be wired in series, in phase to create the "giant" humbucker.

Fixed it for ya. If they’re wired out of phase and placed right next to one another, they will cancel out almost all of the signal.

Basically, ground from pickup 1 is connected to hot from pickup 2, and taped off. Then hot from pickup 1 goes to the volume pot (or output jack), and ground from pickup 2 goes to ground.

But - totally agree that shielding needs to be looked at first.

 

[vindibona1]

That's a lot of work to get rid of some hum.

Before deciding what to do, it would make more sense to figure out what is causing the hum. Two poorly matched coils will create hum in a humbucker. Sloppy shielding will allow hum in the circuit.

For the first you must measure the resistance of the individual coils. Then rewind the coil of your choice. Or partially unwind one of the coils until the resistances match. That's a pretty tall task for most people, to say nothing of building or buying a coil winder. For the second, the remedy is to a good job of shielding the guitar. That means using shielding tape (copper foil) or shielding paint and making sure the ground circuit has no loops. The second recommendation is usually the way to go.

To answer your question, the two single coil pickups should be wired in series, out of phase to create the "giant" humbucker.

First shielding. The bass is now fully shielded. I put copper tape in both the cavities, soldered where the seams met and tested for continuity. I then put the humbucker back in and this time wired it up passively. This past week I put an Audere pre-amp in my MIM jazz so I had a completely wired control panel. All I had to do was wire the hot to the middle of the first pot and the common and two grounds to the back of that volume pot. Still hum. Perhaps a bit less, but I'm not sure it that's the shielding or lack of active circuitry. Still unplayable.

I had purchased a cheap replacement off of Ebay branded "Fleor" but I can only assume that that one too is defective because it had hum and only measured 4.4k when it was advertised as 8-9k. While I had it up and running I tuned it up and it feels really good. I only wish I could get the darn thing to buck hum rather than suck hum .

 

[vindibona1]

Fixed it for ya. If they’re wired out of phase and placed right next to one another, they will cancel out almost all of the signal.

Basically, ground from pickup 1 is connected to hot from pickup 2, and taped off. Then hot from pickup 1 goes to the volume pot (or output jack), and ground from pickup 2 goes to ground.

But - totally agree that shielding needs to be looked at first.

Thanks. I didn't see your reply until after I updated my progress. As you may have already read, it's all now shielded and shielding is tested with a multi meter for continuity.

Anyone have a spare soap-bar size humbucker that they know works? If that's the issue then it's just a matter of re-hooking the old active control panel backup. Such frustration. All I wanted to do was sell this bass- and I already had a buyer but wouldn't give it to him in this condition. I really don't want to spend $100 for a pickup on a bass that might yield $150. Suggestions?

 

[Killed_by_Death]

Shielding needs to have continuity with the shield side of the output jack. I'd check that.

The shielding of controls cavity & pickup cavities should also have continuity.

 

[rojo412]

So the basic answer of making 2 SC pickups into one giant pickup is easy: YES.
Wire the "+" from one pickup to the "-" of the other, then wire the remaining "+" to the output and "-" to a ground. PRESTO! One big-ass pickup.

You can even add switching, should you so choose, to make it series or parallel.

 

[Bruce Johnson]

To make two single coil pickups into one humbucking pair, you have to do two things:

First, the two coils need to have opposite polarity magnets. That is, one coil has to have the magnets all north up and the other all south up. So, you have to reverse the magnets in one of the coils.

Second, the coils need to be connected so that the current goes through them in opposite directions. They are wired in series, but the opposite of what rojo412 has shown above. The two negative sides are connected together, and the two hot sides become the overall in and out leads.

What he has shown above is simply two single coil pickups wired in series, not a humbucking pair. Two single coil pickups in series will capture twice as much noise as one.

 

[202dy]

To make two single coil pickups into one humbucking pair, you have to do two things:

First, the two coils need to have opposite polarity magnets. That is, one coil has to have the magnets all north up and the other all south up. So, you have to reverse the magnets in one of the coils.

Second, the coils need to be connected so that the current goes through them in opposite directions. They are wired in series, but the opposite of what rojo412 has shown above. The two negative sides are connected together, and the two hot sides become the overall in and out leads.

What he has shown above is simply two single coil pickups wired in series, not a humbucking pair. Two single coil pickups in series will capture twice as much noise as one.

Forgot about magnet polarity. Thanks for the catch.

 

[rojo412]

Oops, my bad. Bruce is way better at this stuff than I am. Listen to him!

 

[BruceWane]

All of the stuff posted is correct, but I would assume that a Duncan designed single coil set would be built to cancel hum, IOW one of the pickups is reverse wound/reverse polarity. So really all you're doing is taking a standard jazz bass setup and moving the two pickups very close together. This being the case, you can essentially wire them up just as you would a normal jazz bass, just wire them both to the same volume pot. This would be a parallel wiring scheme. You could add a switch for series/parallel switching. You could hard wire them in series, but remember those pickups were designed to be wired in parallel so series wiring might not give you a sound you want all the time. May be pretty dark/muddy. If it were me, I'd go with a series/parallel switch. You could do it with a push/pull pot if you don't want to drill an extra hole.

 

[BruceWane]

BTW - quick way to check those pickups for reverse polarity magnets is to see if they attract or repel each other when pushed face-to-face. If they stick together, the magnets are reverse polarity, which in my opinion makes it 99.9% likely that one of the pickups is also reverse wound.

 

[two fingers]

Just stick them right beside each other. In essence it's like wiring any other jazz bass but the pickups are right beside each other. They should be wound for hum cancel anyway.

Run them to a series/single/parallel switch and then to the volume pot for more tone options. I had Hammersmith do that on my bass and I LOVE it. One of the mini toggles it neck/both/bridge and the other is series/single/parallel for the bridge pickup. You could do the same with a couple of jazz pickups. Put one in the 60s and one in the 70s position maybe? Lots of cool options.

(Pic from when it was new still has the plastic on the guard which is why it looks scratched to bits.)

 

[FugaziBomb]

Before rigging up a DIY humbucker, I'd try and track down the source of the hum. Of two pickups are noisy in the same bass, I would count out the pickups as the problem and probably just rewire the whole thing from the ground up.

 

[40Hz]

FWIW most cheap pickups are a crapshoot when it comes to things like that. I’d suggest getting any inexpensive pickups you buy from Guitar Fetish. The quality is quite good and the prices are right. They also have frequent sales.

Better yet is to spend a little more and get yourself some Bill Lawrence designed pickups from Wilde Guitars. Amazing quality for true bargain prices. Wilde pups get a lot of love around here.

 

[ctmullins]

Better yet is to spend a little more and get yourself some Bill Lawrence designed pickups from Wilde Guitars. Amazing quality for true bargain prices. Wilde pups get a lot of love around here.

Great suggestion, but Wilde doesn’t make anything in the EMG35 size. An L90 can be made to fit (and would sound fantastic) but is still above the OP’s stated budget.

 

[vindibona1]

I did find a solution so no need to alter the bass. I found a Chinese pickup and initially I thought it was defective, but I didn't understand the wiring of it and no diagram. Two black wires and a red and white twisted pair. What I didn't realize was that one of the black wires was the hot the other the ground. So when I finally put the meter on those two the ohms came up to acceptable levels. If only they had a diagram in the package to show us newbies what all the wires are.

I did create one more problem for myself... The "pad" on the circuit board for what I believe is the ground wire "in" connection became disconnected entirely and I could not repair it. I put the ground wires that were to to to that pad with the rest of the grounds. I'm about 90% hum free and only hear the hum when I turn up the treble and mid post or reduce the volume. Any thoughts? I may have to post this on a separate thread.