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Wiring for 1 humbucker. 1 tone. 1 volume? I did something wrong.

Discussion in 'Tele-Technical' started by BlerpityBloop, Jul 9, 2014.

  1. BlerpityBloop

    BlerpityBloop TDPRI Member

    43
    May 14, 2014
    San Diego
    So on my recent build I just wanted 1 solitary humbucker in the bridge position. No neck pickup, which obviously means I don't need a toggle switch. I have sound, my pickup and wiring works....BUT the tone knob seems to control both the tone and volume. and the volume also controls the volume. And it also may be a little quiet all over. And I can't figure out why.

    So:

    I have a tone pot. a volume pot. an output jack. a humbucker. a .022uF tone cap.

    Picture is attached. (V) and (T) are the volume and tone caps, respectively. I haven't included any of the ground wires in that diagram. I think my grounds are fine.

    I THINK the problem is that tone cap. It should connect the V and T pots, rather than being folder back and ground to the back to the T pot. I skipped the treble bleed cap, this round for simplicity.

    Or....I don't know. Kinda scratching my head here. It SHOULD work. I'm happy to rewire this thing from the ground up, how would you wire up just a humbucker?
     

    Attached Files:


  2. dsutton24

    dsutton24 Poster Extraordinaire Gold Supporter

    Dec 29, 2010
    Illinois
    Did you ground the third lug of the volume pot? The tone cap is wired correctly. Are the controls mounted on the usual metal control plate, or something else? If it's 'something else', you need to make sure there are good grounds to each pot, the bridge, and output jack.
     

  3. BlerpityBloop

    BlerpityBloop TDPRI Member

    43
    May 14, 2014
    San Diego
    Yes, third lug of the volume pot has been ground. The 3rd empty lug of the tone pot is just hanging out (i usually clip it off, don't know if it makes a difference).

    Ahhhhhhhhhh, so, I did a rear route for the control cavity, the pot shafts stick out of the top of the guitar. So it's 'something else'....but I'm not getting any buzz or hum, the grounds seemed secure on my multimeter. (touched one prong to the pot shaft, the other prong to the bridge plate, got a 000 reading)

    *EDIT* I just rechecked the multimeter, one prong on the volume pot shaft that sticks out of the body, the other prong on the bridge plate (which squashes a splayed ground wire). Got a reading of 005, so......yeah....i have continuity...but something is wonky.
     

  4. dsutton24

    dsutton24 Poster Extraordinaire Gold Supporter

    Dec 29, 2010
    Illinois
    If you measure from the nut on the output jack, do you get continuity to both pot shafts?
     

  5. KokoTele

    KokoTele Doctor of Teleocity Vendor Member

    Age:
    42
    Mar 17, 2003
    albany, ny [not chicago]
    If the tone is making things quiet and reducing volume, it's likely that the tone cap is too big. Someone else just posted about that same problem this week.

    Can you post a picture of your wiring?
     

  6. BlerpityBloop

    BlerpityBloop TDPRI Member

    43
    May 14, 2014
    San Diego
    Just did it now. 000 reading. I have continuity on both pot shafts to the output jack nut.
     

  7. dsutton24

    dsutton24 Poster Extraordinaire Gold Supporter

    Dec 29, 2010
    Illinois
    Good.

    500K pots and .022µF (or thereabouts) cap? What pickup are you using? Is there a possibility that the cap lead that's connected to the pot lug is touching the pot case?
     

  8. dsutton24

    dsutton24 Poster Extraordinaire Gold Supporter

    Dec 29, 2010
    Illinois
    Another thought, set both controls to about their midpoint. Measure from the nut on the output jack nut to all six pot terminals. Only one terminal, that third lug on the volume pot, should read close to 0 ohms. The other five should be at least several hundred, probably thousands of ohms. Bet you're going to find the middle lug on the tone control is shorted to ground somehow. Look at that tone cap carefully.

    Is the control cavity shielded? It's a common problem in Epiphones and the like, the pot lugs are riveted to an insulator, and you can end up with pot lugs shorted to the shielding, causing all sorts of silliness. The fix is to remove the pots and add a couple of layers of tape to the back side of the insulator where the lugs are riveted.
     

  9. BlerpityBloop

    BlerpityBloop TDPRI Member

    43
    May 14, 2014
    San Diego
    -Control cavity unshielded
    -The pickup is a bog standard GFS humbucker, just wanted something cheap and cheerful for this build, which is a guitar for playing slide only. Gritty, filthy delta blues slide..mmmmmmmmm....
    - .022uF cap was the recommended and standard value, but I'm happy to swap it out.

    I need to just walk away from this guitar for the evening lest I start banging my head against it. I'll try these suggestions first thing tomorrow, i suspect something is up with the cap. While I have it open I'll take some photos. Just promise not to judge my soldering job (!).
     

  10. dsutton24

    dsutton24 Poster Extraordinaire Gold Supporter

    Dec 29, 2010
    Illinois
    Sometimes walking away for a bit is smart. Someday I may tell you why my truck hasn't run in two days...:oops:
     

  11. BlerpityBloop

    BlerpityBloop TDPRI Member

    43
    May 14, 2014
    San Diego
    Ha.

    Well, thanks everyone for your help. This forum is tremendous.

    Mostly I wanted to make sure that my wiring plan was sound, cap gets bent back from the middle tone prong and ground to the top, hot wire from pickup to left prong of volume pot.etc etc.

    the grounds and whatnot can be troubleshot tomorrow, though after reading everyone's advice I think there is a problem with the tone cap connection...or maybe my two pots aren't talking to eachother....or maybe it's a loose wire....
     

  12. Glen Smith

    Glen Smith RIP

    Aug 20, 2011
    Canada

    Attached Files:


  13. KokoTele

    KokoTele Doctor of Teleocity Vendor Member

    Age:
    42
    Mar 17, 2003
    albany, ny [not chicago]

    Good idea to put it out of your mind for a while. When I was in college, I had roommates who thought of me as their tech support staff. When I'd get stuck on a problem, I'd say "I need to f-off on this for a while," and sure enough, an hour or so later the solution would present itself. It was the longest running joke we had.

    The symptoms you described don't match with the the things you're checking, though.

    I think the first step we need to follow is to isolate the problem. If it were me, I'd disconnect the lead from the volume to the tone pot and then play to make sure that it sounds right and the volume control works normally. If not, then we've got a much smaller system to troubleshoot.

    After that, reconnect the tone control and see how the behavior changes.

    What type of cap are you using? Do you have a way to directly measure its value? A tone cap that is capacitating too much would fit with the symptoms you describe. A bad solder joint at the volume pot (or bad pots) would fit as well. Missing or loose connections... not so much.
     

  14. Tuxedo Poly

    Tuxedo Poly Tele-Afflicted

    Dec 19, 2011
    Merseyside UK

  15. Peter Rabbit

    Peter Rabbit Tele-Holic

    Age:
    67
    895
    Sep 17, 2009
    Toronto, Ontario, Canada
    Here's my 2 cents -

    1: the cap may be burnt, did you use a heat-sink on the cap's legs when soldering? If you have a meter, you could check the cap.

    2: you might try "vintage" wiring, where the tone pot is connected to the output of the volume pot rather than the input of the volume pot. (You didn't mention the make and value of the pots, not that it should matter, but...)

    3: as long as the cap is grounded somewhere, it doesn't matter where.

    4: a picture is worth a thousand words.

    (No. 2 may solve your problem)
     

  16. BlerpityBloop

    BlerpityBloop TDPRI Member

    43
    May 14, 2014
    San Diego
    Photo as requested. I am mortified how sloppy this looks. I'm going to re-do everything and clean it up.

    A couple of things you hopefully can discern from this photo:

    - as a general rule I twist ground wires together and solder them as one to the back of pots. I have giant clumsy hands and this works best for me and keeps profanity to a minimum

    - pots are 500k from gfs, don't know the brand

    - there are no heat shrinks on any but two wires, which I didn't even shrink. I have heat shrink, not sure why I didn't use it.

    - despite appearances, the grounding works. I have continuity from jack nut to shafts, to bridge plate. I'll tidy it up regardless and make sure this is so on the next attempt

    - there are quite a bit of exposed "legs" on that tone cap. I'll heat shrink all but the contact point and see if that helps

    - the cap was brand new from gfs (not that this means anything). I have a very nice and hot soldering iron that takes no time at all to heat up contact points, I highly, highly doubt I fried something

    - gfs wires are tiny, nearly impossible to strip, i did the best I could

    - the pickup came wrapped in some sort of electrical tape that seems to be holding wiring in place. I undid one layer, which I think I was supposed to do, and I believe of I unwrap the last layer the pickup will start to fall apart.
     

    Attached Files:


  17. BlerpityBloop

    BlerpityBloop TDPRI Member

    43
    May 14, 2014
    San Diego
    image.jpg Slightly better picture of the tone pot

    And a not so great picture of the volume pot.
     

  18. BlerpityBloop

    BlerpityBloop TDPRI Member

    43
    May 14, 2014
    San Diego
    Tone pot
     

    Attached Files:


  19. Tuxedo Poly

    Tuxedo Poly Tele-Afflicted

    Dec 19, 2011
    Merseyside UK
    Tip for locating capacitor on rear of pot. Place it flat on the pot and locate the legs as in the pic.
     

    Attached Files:


  20. BlerpityBloop

    BlerpityBloop TDPRI Member

    43
    May 14, 2014
    San Diego
    Well that's super handy. I've had my coffee and soldering iron is warming up now.

    If I'm not back in 30 minutes just wait longer.
     

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