LP Volume Controls

[shartom]

You have probably noticed on your Epiphone/Gibson guitars that when both pickups are selected, either of the volume controls acts like a master volume. I've been caught on a few occasions having no sound when I needed it the most.

I rewired my Gibby LP Studio and used it on a church gig this morning. Gibson wires it's pots in a funny way. Not sure if I like the mod or not. Got to play a concert outdoors tonight. I'll be able to crank the guitar so I should be able to evaluate the sound better.

[Whitmore Willy]

Shartom,

If it works out, post a diagrahm of the setup.

[TWANG]

independant volume control is diagrammed all over the web.

I like it, too. And most people seem to prefer it to gibsons standard way.

[RotcanX]

Thing is, Gibsons are wired so that the guitar's output is grounded when the volume is at zero; this effectively 'shuts off ' your amp's input so that you don't get noise out of it with the volume turned off. The alternate wiring method, which eliminates that dead spot where one volume at zero shorts out both pickups, however, does not short the guitar's output so you may find you're getting some extraneous noise out of the amp even with the volume controls at zero. You have to choose which condition is more bothersome. Personally, I think Gibson's take on it is that they gave you a switch to select the pickups and as such you shouldn't be trying to use your volume controls to perform that function.

[shartom]

My Studio is back on the bench. I was doing an outdoor concert last night. I plugged in the Studio to tune up, and the hum was way too loud.

I followed the wiring diagram and it does work except for the hum.

All of the pots sit on a metal plate the same shape as the rear cover.The plate is even stamped with the first letter of the color of the wire. That is a little scary. I wonder who builds these things. Instead of wiring the tone capacitor from one of the outer lugs of the tone pot, they wire it directly between the center lugs of both the volume and tone controls. The guitar went from being too bright to being somewhat muddy

I have modified old Gibsons for my friends without a problem. I read somewhere that this mod, at least I think it was this mod, should not be done on guitars equipped with the steel plate. To me, and I am a retired electronics engineer. this smells like a ground loop problem.

On the good side, I had my trusty Epi 56 Gold top with me. Absolutely no hum. My amp was miked into the sound system and our sound man said it was totally hum free...yes P90's will get the job done.

I'll report back after the Studio comes out of surgery.

[shartom]

I restored it to the original wiring and it works fine. The brightness is back also.

The multiconductor cable coming from the switch is the same as the one used on my Joe Pass. The individual wires are pretty small. I'm sure Gibson is watching the Epi side of the family to see how they can cut some corners.

[carverman]

I followed the wiring diagram and it does work except for the hum.

All of the pots sit on a metal plate the same shape as the rear cover.The plate is even stamped with the first letter of the color of the wire. That is a little scary. I wonder who builds these things. Instead of wiring the tone capacitor from one of the outer lugs of the tone pot' date=' they wire it directly between the center lugs of both the volume and tone controls. The guitar went from being too bright to being somewhat muddy

read somewhere that this mod, at least I think it was this mod, should not be done on guitars equipped with the steel plate. [/quote']

 

If all four pots are screwed down to a steel plate, that should provide a better ground plane,

but it shouldn't cause any grounding problem hum. As far as the tone pot, if the

one side of the cap is soldered to the pot case and the other to one of the outer

lugs and the center lug goes to the center lug of the volume or ONE of the outer

lugs is soldered to the case and the cap is inserted inline between the center tap

of the tone pot and the volume pot, it shouldn't make any difference.

 

The cap and pot is an RC network and should work either way.