How do I add the OMG setting to my series/parallel switch?

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fermata

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Nov 10, 2015
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#1
I've been reading about the G&L L1000, and I'd like to experiment with the OMG setting, which puts a .1uF capacitor in parallel with one coil of a humbucker when switched to series. Here's G&L's circuit: http://www.glguitars.com/schematics/L-1000_schematic_drawing.pdf
And here's how my series/parallel switch is wired:
switching.jpg

On this switch, where would I put the capacitor to cut treble on one coil of the pickup?
 
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#2
I don't think there's quite enough information with what you've given us - we'd need to know which wire pair on the G&L schematic is for the south coil and which is for the north.
 
#8
Killed_by_Death said:
Just install a 100 nanoFarad treble cut capacitor, roll it all the way counterclockwise, & Voila!
Click to expand...
That's not the same. the OMG switch rolls off the treble from one side of a humbucker leaving the high end definition of a single coil giving the effect of a passive bass boost. It also works on series wired basses giving the same effect just with two separate pickups.
 
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#15
That's a pretty clever little thing G&L did there, but seeing as how it's removing highs from one coil & removing lows from the other, you'd think it would be a wash.
Guess not, or they wouldn't call it OMG. I'm assuming there's a middle position on the switch (not shown) that is just regular series mode.
 
#16
Killed_by_Death said:
That's a pretty clever little thing G&L did there, but seeing as how it's removing highs from one coil & removing lows from the other, you'd think it would be a wash.
Guess not, or they wouldn't call it OMG. I'm assuming there's a middle position on the switch (not shown) that is just regular series mode.
Click to expand...
It's not removing that much lows from the second because it's 45x larger then the bass cut and for bass cut caps a smaller value means a higher cut off frequency (cuts more lows) so it's measurable but inaudible.
 
#18
fermata said:
Just found this:
View attachment 1012647
Doing the G&L "OMG" mod to a non-G&L bass
Click to expand...
I actually never got to test this diagram. There is another diagram in the linked thread that is missing:
1ufCapsseries-splitcoiljpg-1.jpg


This wiring schematic yields Series, North Coil OMG, South Coil OMG

As far as I understood the OMG is that since capacitors cut certain high frequencies depending on their value, just like the tone pot cap rolls off highs, this OMG cap cuts highs of one coil, but keeps the lows of both, while retaining a lot of mids as well. I have had this set up in a couple of basses over the years because I really liked the high output. But these days, I seem to be doing back and using parallel and non-OMG coil tap single coil settings...I like a lot of the low-output nuances and sound of your fingers on the strings...or something like that...I still have OMG in my L2500, but not in the black Squier Jazzman I have.
 
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#19
As stated, the OMG mode is used when the G&L Humbucker is placed in Series. A cap is place in parallel with one of the coils which eliminates the humbucking nature of the two coils. In the L-1000 bases, the Green-Yellow coil is toward the neck and the Black-White coil is nearest the bridge. In series OMG mode, the Green-Yellow coil has a 0.1uF capacitor placed in parallel with it. This sucks all the highs from the Green-Yellow coil. The Black-White coil has both the 0.1uF capacitor and the Green-Yellow coil in series with it which allows it to basically pass its full spectrum. It's a noticeable bass boost response. It can be boomy. But it can work with the G&L passive bass cut and the version 2 preamp which tends to boost treble.

G&L stopped doing the OMG caps in the early 2000's. There were a lot of reported noise issues which were partly due to the OMG caps. The older G&L pups had a tendency to pick up noise anyway. And the OMG caps in a two pickup bass were actually hum adding with both pups selected. You can mod those older two pickup OMG basses with 1 wire switch that makes the two pickup / 4 coil configuration hum cancelling again. I am surprised that G&L manufactured a hum adding configuration for 20+ years that has such an easy fix.

Modern G&L basses provide a grounding point for the 2 coil, 4-wire pickups which is also connected to the pup's green wire. In my limited experience with the newer G&L pups, they are quieter. Both of my import G&Ls from recent years had grounded pickups and a shielded electronics and pickup cavity. If doing wiring mods on those basses, the green wire must stay connected to "ground". In the older basses, the green wire going to the coil was floating like the other three wires.
 
#20
@DavePlaysBass, Since you seem the most knowledgeable, would the below drawing render a Parallel/Series/OMG using a 3 position 8 pole switch? meant for a 4 wire single humbucker

N is neck coil, S is bridge. Red lines are hot leads, black negative/ground, and green are just solid wire. Blue is the .1 uf cap you mentioned.

3waySPO.jpg


Edit: I created this drawing in powerpoint to try to be neat.... sorry if confusing.
 
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