Humbucker/Single Coil One Volume, One Tone

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by robbieboyette, Jan 21, 2006.


  1. robbieboyette

    robbieboyette Member

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    Running a H/S/S config with a single volume and a single tone control. Humbucker is WCR HERC model and single coil is WCR SR single coil.
    Question is this...the HERC sounds just the way I want it. The SR is a little bit bright.
    Is there a way to "fix" the SR without mucking up the HERC? Maybe some sort of capacitor attached to the lead of the pickup before it gets to the switch?
     
  2. John Phillips

    John Phillips Member

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    What volume and tone pot values are you using?

    You can certainly add a small cap, but if you're using 500K pots, a resistor might give better results - slightly fatter but still clear, without rolling off as much of the high top-end. If you parallel the pickup (to ground) with a 470K resistor, that will simulate a 250K volume pot when the single coil is selected.

    If you are already using 250K pots, try a .001uF (or smaller) cap.
     
  3. robbieboyette

    robbieboyette Member

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    Thanks for the response John. Yes I am using 500k pots in that guitar. So if I simply solder a 470k resistor from the switch where the single coil lead is to ground that should do the trick? Cool! I'll give it a shot. Again thank you very much! :)
     
  4. robbieboyette

    robbieboyette Member

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    Okay John...that didn't work at all. I think I'm misunderstanding what you're saying. Here's what I did: I took a 470k resistor and went from the terminal that the "hot" wire from the SR pickup is hooked to the 5 way switch and connected it to the ground of the tone pot. That's what I understood you to mean when you said "parallel" Of course the guitar just shorted out and made no sound at all.
    So what am I doing wrong? If you don't mind could you spell it out in detail so that even my underused brain can understand? I'm obviously a lot stupider than I thought....
     
  5. John Phillips

    John Phillips Member

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    That should have worked... assuming the wires from the resistor didn't touch anything else. Check that first.
     
  6. robbieboyette

    robbieboyette Member

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    No, they didn't touch anything but the pickup lead and switch terminal on one end and the tone pot ground on the other. Instantly cuts the guitar off completely...
     
  7. John Phillips

    John Phillips Member

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    Does it cut the guitar off in the humbucker-only position? If so, it must be touching something it shouldn't - check the tone pot end as well in case it's touching the hot terminal of the pot or anything (obviously I have no idea of the orientation of anything here!).

    If it just cuts the sound off when the single coil and both pickups are selected, you could possibly have a shorted resistor, but it's highly unlikely with a 470K (or could it be a 470-ohm resistor? - I've come across this mistake recently in an amp, the other way round).

    Are you sure you didn't disturb some other wire or connection while you were in there? The way you've connected it is definitely correct.
     
  8. robbieboyette

    robbieboyette Member

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    Oops...it's a 470 ohm resistor. Damn it..back to Radio Shack.
     
  9. John Phillips

    John Phillips Member

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    :)

    If it makes you feel any better, the amp I was talking about was a Vox AC30 where another tech (not one familiar with tube amps, to be fair, although he's an expert on digital gear) had replaced the screen resistors with 100K instead of 100 ohm, and couldn't work out why it was so quiet... ;)
     
  10. robbieboyette

    robbieboyette Member

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    Great job of diagnosing...you're better than "The Great Kharmak" as far as your incredible powers! :) The 470K resistor DOES work! Heh-heh-heh...I never would have figured that out. It seems to roll off just a touch of the real high end presence that the single coil had a tad too much of with the 500k pots. Thanks bro...
     

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