• Guys, we've spent considerable money converting the Les Paul Forum to this new XenForo platform, and we have ongoing monthly operating expenses. THE "DONATIONS" TAB IS NOW WORKING, AND WE WOULD APPRECIATE ANY DONATIONS YOU CAN MAKE TO KEEP THE LES PAUL FORUM GOING! Thank you!

Another 50s wiring thread.

JR.Deluxe

New member
Joined
May 4, 2003
Messages
570
Sorry . I looked through some threads but gave up.

So when my tone control is on 10 it sounds like its on zero. But on 8 it sounds like its wide open like 10 should be. It sounds good besides this anomoly and rolls off from 8 to zero normally. Another issue thats probably unrelated is that my 2 p90s are out of phase and i need to flip some magnets. Whatz the deal?
 

PaulD

Active member
Joined
Jun 25, 2007
Messages
673
That's a strange one, I haven't come across that before! The tone control pot is wired as a variable resistor in series with the cap, when the pot is on 10 it is a very high resistance (usually 500K) and virtually no signal passes through the cap to ground, when the tone control is turned down the resistance progressively decreases allowing more of the high frequencies to be shunted to ground through the cap. The symptoms you describe suggest that the pot resistance is peaking when it is on 8 and then reducing again as it is turned up to 10. I can't quite visualise how the pot could be faulty in a way that would cause this but also can't think what else it could be.

If you have a multimeter you could test the pot by connecting the meter between the lug on the tone pot that the capacitor is connected to and the lug that is grounded (this can be done with the pot still in circuit - no need to remove it). With the pot on zero it should read a very low resistance (a few ohms at the most), then as you turn the pot up the resistance should progressively increase up to a maximum (500K) when it on 10.
 

JR.Deluxe

New member
Joined
May 4, 2003
Messages
570
When i got the guitar open again i'll measure the pot. Right now im just happy to have my guitar back in action and can tolerate the wierdness of this problem. The pots probably are bad. Its from some prewired harness that i paid double its worth for out of laziness. After about 5 minutes of use one of the volume pots completly failed and i stuck an emerson in there. Volume works good now but the tone controls are wonky as described.
 
Top