Volume pot query for an SG

[Umfufu]

I just finished rewiring an Epiphone SG for a friend of mine.
I replaced the pickups, wiring, pots & capacitors.
The only original parts left inside it were the switch (3-way) & the ground wire from the bridge.

I followed the Seymour Duncan wiring diagram.

http://www.seymourduncan.com/pdfs/support/schematics/2h_2v_2t_3w.pdf

The switch seems to be wired correctly but when it's in the middle position the 2 volume pots don't act independently.

If the both volume pots are at 10 & I turn either one of them down, the volume of both pickups is lowered.

As it turns out, my friend thinks this set up will actually suit him better cos if it's in the middle position he won't have to turn down both knobs in order to cut the sound.
However, it wasn't my intention to wire it this way so, for my own knowledge, I'd just like to know why this is happening.

[Chuck H]

Thats the way it is with the stock SG wiring. If you look at the schem for what you did, you'll see that either volume pot can present a "load" to the the "+ jack" in the middle position. To achieve what you want would require wiring the pots backward with respect to the pickup and switch. You could then get independant pickup control in the middle position. But it would be at the expense of extra noise in ALL positions with the guitar volume down. This is caused by an elevated ground at the amplifier input. This would be especially noticable in high gain amps or when using preamp driven effects like OD and distortion pedals.

FWIW I just did an SG for a friend too. And after considering the pros and cons, I went with the stock pot wiring. But I did put a 1000pf bright cap on the bridge side volume control. Considering how the controls are typically operated, I don't expect the mild "tone control" effect on the neck pickup to be a problem.

Chuck

[Sock Puppet]

I haven't an SG (or a Gibson!) but that looks fine to me.

Because the wiper and ground of both volume controls are in parallel then by turning down one control, that signal is controlled normally while the other has to feed into a progressively smaller resistance until it becomes shorted to ground.

HTH.

S.

[Sock Puppet]

Pipped by 18 minutes?

Chuck, your reply wan't there a moment ago.

Yet my home page shows only my reply?

I'm going back to bed,

S.

[bob p]

the board does seem to be having probelms tonight.

[Umfufu]

Thanks guys.

Just realised that I'm dumb. I was sure the 2 volumes were supposed to be independent when the switch was in the middle position.
Just put it down to me being a bass player.

Thanks for the responses.

[robrhy]

You need to wire your p/ups like this

[Umfufu]

Thanks Robrhy,

I'm going to leave it as it is for now cos he reckons that setup will actually suit him better.

Any idea if wiring it with the 2 volumes working independantly would cause a hum increase?

[robrhy]

Thanks Robrhy,

I'm going to leave it as it is for now cos he reckons that setup will actually suit him better.

Any idea if wiring it with the 2 volumes working independantly would cause a hum increase?

I've never wired them like that so i can't say,but i've never heard anyone say it did.