EB-3 controls 'non-problem'

Discussion in 'Luthier's Corner' started by happy_tom, Jan 9, 2014.

  1. happy_tom

    happy_tom Active Member

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    Hi. Like every owner, I've got a beef with stock EPIPHONE EB-3 electronics.

    These have 2 vol + 2 tone controls and a simple 3-way rotary (bridge/both/neck). No choke.


    The problem is, when both pickups are selected and you wanna roll the volume off one just slighty, it ABRUPTLY cuts off at about 9.3 or so.
    There's absolutely no tiny sweet spot, in fact you can hear a little >click< when it cuts off.

    I know what you'll suggest, so let me tell you, I have done the following so far:

    Installed 4 audio taper 500K pots with:
    -stock independent wiring
    -tried gibson modern wiring, both stock and independant volume
    -tried gibson 50s wiring, stock and independent volume (and it works so well on guitars)

    IT DIDN'T HELP AT ALL. When both pickups are selected, rolling off one of them below 9.4 will still result in cutting off that pickup abruptly and completely.

    As you know, in 'both' position the neck pickups almost completely overpowers the mini humbucker, so I wanna take just a bit off, but can not... :dunno:


    Is that just the nature of the beast?
    Does the problem lay it the rotary or the pickups?

    Would a blend control instead of rotary make any difference, or would one of the pickups still just cut off at ceratin point?
     
  2. weemac

    weemac Active Member

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    You want linear taper pots for the volumes. That will help you find the sweet spots.
    Treble Bleed Capacitors in the volume pots will help too..

    Eden.
     
  3. happy_tom

    happy_tom Active Member

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    I've done that and it's still the same :dunno:

    I forgot to mention: when I select EITHER neck or bridge pup (position 1 or 3), the volume of that pickup will roll down as smoothly as anything.

    But with both selected (position 2) it's the 'clik', and they're either on or off... :hmm:
     
  4. weemac

    weemac Active Member

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    It may be that the impedance difference between the pickups is to great as the bridge is about 8kohmish and the neck is 20+kohm. I had a 68 eb3 and there was no such thing as a sweet spot with it either.. Perhaps that is why the current Sg basses have redesigned pickups (tb+ instead of the sidewinder)

    Eden.
     
  5. javamagic

    javamagic Well-Known Member

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    I think you'll find the current Epiphone EB neck pickup is only about 8K so definitely not a repro of the old "mudbucker". Sorry I can't shed any light on the problem but it does sound as if there is a crossed connection somewhere, perhaps the switch as suggested? :hmm:
     
  6. happy_tom

    happy_tom Active Member

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    Thanx for the thought.

    I have been pondering this and came to the conclusion that there MUST be something in the switch, or the way it's connected.


    If the controls work smoothly for one pickup that is selected at the time (but not when both are on), then it's safe to assume they would work smoothly if I just bypass the switch and connect the pickups to their dedicated two controls...


    ...which is one way to mend things. I might as well try it, since I fried the bridge volume with all that soldering... :dunno:


    Oh, just an observation if anybody is reading this: stock EB3 mini hubucker actually has 4 wires for coil splitting...
    Maybe I could use the 3 way for coil split / phase or series/parallel experimentation? :hmm:
     
  7. javamagic

    javamagic Well-Known Member

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    If the rotary switch has two (or more) contact wafers there may be an un-noticed jumper between them causing the problem. I know I've had trouble with Fender switches caused by similar wiring links. Good luck with sorting it.
     
  8. bea

    bea Well-Known Member

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    No, it is not. It is 1.2 K. You might install a resistor in series with it when it is parallel to the bridge pickup. I would juse an adjustable resistor of 25 K or even 50 K. beware to insert it in such a way that it is only effective when both pickups are on.

    And consider to replace the pole screws by a 6mm x 6mm steel bar below the cover. The pickup will sound a lot better than stock.
     
  9. javamagic

    javamagic Well-Known Member

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    The Epiphone neck pickup is listed as being 8K. If it's only 1.2K as you say there's something very wrong and we are all being misled.
     
  10. bea

    bea Well-Known Member

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    I have measured 3 pickups, 2 from 2011, one a few years older They are all 1.2 k.
    How old is it? Maybe they have changed the specs.
     
  11. Bubbalou88

    Bubbalou88 Member

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    Removed for incorrect comment
     
    Last edited: Sep 22, 2020
  12. Bubbalou88

    Bubbalou88 Member

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    Yep, to get the best reading the pickup should be disconnected and tested direct to the pickup leads. Also if in the circuit you need to put the pickup selector to Bridge only so the Neck circuit doesn't load it. Connect instrument cable to the output jack and with the unused end (that normally connects to the amp connect ohmmeter to the tip and the sleeve of the cable plug. Insure the volume and tone controls are in full (10) position and it should read close to 8K
     

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