What did I do wrong?.

D

DracoAran

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JB_QP.jpg


It's a bridge JB trembucker, a middle Quarter Pound RWRP Tapped, and a Stag Mag at the neck.

The tone pot is a No Load. Both pots are 250K. When I take the tone pot out of the circuit, the load is equal to that of a pair of 500K pots.

Anyway, when I pull the DPDT, it splits the humbuckers and taps the Quarter Pound to a lower output.

The issue I am having is that I am not getting hum cancelling in positions 2 and 4. I get hum in those positions even when the DPDT is pushed in. It took me a long time to track down a Quarter Pound RWRP Tapped, just to find out that it doesn't cancel hum.

Was I supposed to use a regular Quarter Pound?.

On another note, whoever said that a Duncan JB splits nicely needs to get their ears checked. I think I am gonna try an Anderson H2+ or perhaps an H3, to keep up with the output of the Stag Mag and the Quarter Pound while in humbucker mode, and get a better split tone.
 
Re: What did I do wrong?.

The QP never cancelled hum.
it's a single coil.

Without the humbucker tapped there's no way it WOULD cancel hum in 2 and 4.

what's the resistance of one half of each of those coils/ the QP tapped?

If they're not equal, then same story, not going to cancel hum.
You ARE cutting out the correct coil of the humbuckers, correct?
 
Re: What did I do wrong?.

with a rw/rp middle pup, youll need to reverse the phase of the two buckers.

when using single coils with buckers usually you dont need rw/rp, only when you have two singles next to each other
 
Re: What did I do wrong?.

Jeremy, the pickups are all in phase. If I reverse the phase of the humbuckers, I would be creating a new problem.
And yes, as you guys can see, the correct coils on the humbuckers are getting cut out.

I just find it odd that hum is not cancelled when the DPDT is pulled. What's more odd is the humbucker + single combination humming too.
 
Re: What did I do wrong?.

Then you have a magnetic polarity issue.

To cancel hum you need two similar coils, wired 'out of phase'. Of course, this also inverts the signal polarity so you need also to invert the magnet on one coil to bring the signal back. Hum doesn't care about magnetic polarity, only the coil polarity.

In short, you'll need to either flip the magnets in the humbuckers or rewire them so that the other coil is the one that is grounded. And then you'll have to play with the wiring until you get 'in phase'.
 
Re: What did I do wrong?.

What I would do first, because its the easiest, is to just move the ground on the DPDT to the lower, left terminal of the 5-way. That will give you the adjustable coils of the humbuckers instead of the stud coil. Try that, and see if that works. (Or helps.)
 
Re: What did I do wrong?.

ArtieToo said:
What I would do first, because its the easiest, is to just move the ground on the DPDT to the lower, left terminal of the 5-way. That will give you the adjustable coils of the humbuckers instead of the stud coil. Try that, and see if that works. (Or helps.)
Click to expand...
Word.
I thnk that sounds better, too.

And humbucker/single combos will ALWAYS hum.
three coils=one humming coil.
 
Re: What did I do wrong?.

TheGZeus said:
And humbucker/single combos will ALWAYS hum.
three coils=one humming coil.
Click to expand...
Yup.

I know with a H-S-S setup, if your bridge is split in 2 (or whatever you call the bridge-mid combo), you need a RWRP neck for hum cancellation.
 
Re: What did I do wrong?.

Kent S. said:
Draco, here ... just add the blue jumper (ditching the ground), and reroute the tap connection as shown (less noise). This will split the pups to the outer coils automatically in the 2&4 positions, and whenever the tap switch is pulled (so you can have split HBs in positions1&5, which also taps the QP like you want).
Click to expand...

Thanks, but the setup I have going has a humbucker mixed with a full output Quarter Pound in positions 2 and 4, which is a really cool combo, because the middle single has such character, like a total brat that wants you to know he's there. By pulling the DPDT I get the S-S-S setup with the middle pickup tapped down to an output that balances well once again. Although the JB did turn out to have the kind of split that just hurts my feelings, because the output doesn't match, and the tone is more uninspiring than an indonesian ceramic bridge single coil. So next up is an Anderson h2+ or h3, or maybe a Rio Grande Muy Grande. I thought about a Dimarzio Bluesbucker, but I don't think it's gonna have enough low end, or enough output to keep up with the other pickups.

Also, in your schematic, the splits are not getting a ground anywhere, and I don't understand why you moved the middle hot wire to a terminal that combines it with the tap when pulled.
 
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Re: What did I do wrong?.

DracoAran said:
Also, in your schematic, the splits are not getting a ground anywhere, and I don't understand why you moved the middle hot wire to a terminal that combines it with the tap when pulled.
Click to expand...

Hey Draco; The idea of taking a split to ground is a bit misleading. You take the red/white to green to split to the stud coil, and to black to split to the adjustable coil. Since green generally goes to ground also, the schematics show it that way. Kent's just showing you taking the split to black - ie., using the other coil. :)
 
Re: What did I do wrong?.

It all depends on which coil of the humbucker is active when the bucker is split. The middle pu needs to be RWRP relative to the active coil. If it doesn't cancel hum with one, it should with the other. (At least most of the hum -- a lot depends on the relative output of the tapped QP vs. the one coil from the JB humbucker.)

Regardless, you will still get hum when using the Quarter Pounder with the humbucker because you are adding a non-humbucking single coil to the signal. You won't get quite as much hum but you will still get some because there isn't a 4th coil to cancel the hum of the single coil.
 
Re: What did I do wrong?.

So, selecting the coil with the screw pieces would look something like this?:

7db06028.jpg


I would use the push/pull to jumper the black wire to the red and white.
 
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