Q: Wiring Split Humbucker Behavior: odd or normal?

[engine247]

My apologies if this is long. I will try and explain it as tersely as possible.

I installed a new bridge pickup and figured I may as well replace the pots. For fun I decided to install 2 push-pull pots (volume) and split both humbuckers (slug side on the neck screw side on the bridge). For more fun I decided to try the treble bleed mod as well on both volume knobs. (capacitors and resistors are cheap so I couldn't resist)

I finished and everything seemed to work just fine. Then I noticed the following when 3-way switch is in the middle position and both pickups are split (maybe even just one but both for sure... it was late). Starting with both volume knobs at 10, if I move one (either or) of them to 9-9 1/2 there is a volume dip. If I then move it a little further to 8-8 1/2 the volume goes back up but to a higher volume than when both were at 10.

It only happens in the middle position when splitting. I don't necessarily see it as a problem and I assume it is probably just a side effect of the treble mod + splitting but I am curious if anybody knows what is going on.

Cheers.

 

[Artie]

Re: Q: Wiring Split Humbucker Behavior: odd or normal?

Since no one else chimed in before this made it to page 2, let me toss in a "maybe" or two.

Splitting to the neck-slug and bridge-screw is unusual. Nothing wrong with it, its just not the norm. Since a vibrating string has "nodes", there are instantaneous points that are out-of-phase. You may have those two coils under just such nodes. So . . . as you turn down one volume control, you're reducing the minute amount of out-of-phase information presented to the other pup. Thus, the volume peaks somewhat.

Its just a thought 'til someone comes up with something better. Like you wired it wrong.

Artie

 

[jeremy]

Re: Q: Wiring Split Humbucker Behavior: odd or normal?

what artie said is along the same lines as what i am thinking. you are probably getting some cancellation at certain relative volumes

 

[tone4days]

Re: Q: Wiring Split Humbucker Behavior: odd or normal?

he could test that easily enough by playing notes somewhere else on the neck to see if he gets the same cancellation effects ...

my money is on an unintended consequence of having two volume knobs in the circuit at the same time ... like when the LP cats experience agita with the pup selector in the middle

either that, or an unintended phase problem from the way he is splitting slug from one and screw from the other

good luck
t4d

 

[Rich_S]

Re: Q: Wiring Split Humbucker Behavior: odd or normal?

The volume control behavior sounds like how 2 volumes work when pickups are out of phase - if the controls are balanced, the phase cancelation makes it sounds thin and weak, but when you turn one down it reduces the cancelation and the pickup that's still wide open sounds stronger and louder.

How this relates to the splitting is impossible to say without a good, long look at the as-built schematic.

 

[Artie]

Re: Q: Wiring Split Humbucker Behavior: odd or normal?

he could test that easily enough by playing notes somewhere else on the neck to see if he gets the same cancellation effects ...

Good point.

 

[engine247]

Re: Q: Wiring Split Humbucker Behavior: odd or normal?

Thanks gentlemen. I'll have a further look tonight. Splitting the slug side and screw side was more or less a semi-random choice to see what it sounded like. Is screw side & screw side more the norm?

 

[PFDarkside]

Re: Q: Wiring Split Humbucker Behavior: odd or normal?

The volume control behavior sounds like how 2 volumes work when pickups are out of phase - if the controls are balanced, the phase cancelation makes it sounds thin and weak, but when you turn one down it reduces the cancelation and the pickup that's still wide open sounds stronger and louder.

How this relates to the splitting is impossible to say without a good, long look at the as-built schematic.

I agree. That's how the Page wiring is. I wonder if somehow in the split wiring it inadvertantly flips the phase of one of the pickups?

Edit, I just played to confirm, and the pickups are definately out of phase on that setting. Do you have the schematic(s) you used?

 

[engine247]

Re: Q: Wiring Split Humbucker Behavior: odd or normal?

I basically used the SD schematic:
http://www.seymourduncan.com/support/schematics/2h_2v_2t_3w_2pp.html

but made the volumes the push/pulls instead of the tones.

to decide which side to split I used:
http://www.seymourduncan.com/support/schematics/coil_splitting.html

looking again I actually split the inner/slug side of the bridge and the outer/screw side of the neck. I really didn't stop to think about phase. (I was having too much fun soldering)

 

[Robert S.]

Re: Q: Wiring Split Humbucker Behavior: odd or normal?

Having a JP wired guitar sometimes comes in handy. It is definately a phase issue that is being caused by the schematics you used.

To split to the screw bobbin without the phase issue, wire the neck pickup black hot and green to ground and use the push pull pot to connect the red/white wires to the neck pickups black lead instead of ground.