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Cort Steinberger Copy Wiring Diagram and Help

Discussion in 'Pickups & Electronics [BG]' started by GKon, Mar 6, 2013.


  1. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    Hi Fellas,

    I have a cort steinberger copy 4 string that has some electronics issues.

    I inherited the bass and, when I got it, the volume pot was shot. I had never tried replacing guitar electronics, so I gave it to a friend of mine to repair. He replaced the volume pot with another (not sure if they are all interchangeable. I assume not) and gave it back to me but, since then (many years ago) it still never worked right. Low volume, lots of noise, the knob on the volume pot doesn't move freely, etc etc.

    Long story short, I'd like to replace the volume pot and find the wiring schematic for this setup because, it seems, in the process of moving it around, another wire or 2 have come loose.

    Keep in mind, I used to build custom motorcycles, so I have soldering know how, I just don't know where all the pretty wires connect ;)

    Thanks,

    Kon
     
  2. 96tbird

    96tbird PLEASE STAND BY Supporting Member

    I think this may be the right one if its a passive bass. ImageUploadedByTalkBass1362577726.389861.
     
  3. Crater

    Crater

    Oct 12, 2011
    Dallas, TX area
    I used to own one of these...yes, the diagram above is correct.
     
  4. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    96tbird, thanks so much for the quick reply and the diagram. I appreciate it.
    However, the bass I have has EMG P-J style pickups that use a 9volt battery, which, if I'm correct, makes it active? Would you happen to have a schematic for that (am I just asking too much?) :)

    Looking at the wiring, however, I notice that the positive (red) battery wire comes out of one of pickups (not sure which one, haven't taken it apart that far) into the battery terminal, and the negative battery wire (black), goes off to the input jack. Other than that, would the rest of the wiring be the same?

    Also, my question regarding the type of volume knob. Do they come in different resistance, or output, or whatever? I will need to replace the volume pot that is there now. If it has to be something specific, how do I know what I need (the one in there now is not original)?

    Thanks a million.
     
  5. 96tbird

    96tbird PLEASE STAND BY Supporting Member

  6. SGD Lutherie

    SGD Lutherie Banned Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    This is from the old EMG instruction sheet:

    emg_PJ_wiring.
     
  7. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    96tbird, SGD Lutherie, thank you very much!

    SGD Lutherie, the diagram you posted looks spot on.

    Now, regarding replacing the volume pot, does that have to be a specific item, or are they all the same? I notice some sort of resistor, or capacitor or some such item attached to it..

    Much thanks,

    Kon
     
  8. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    bump

    Trying to find out how I figure out what new volume pot will work. The old one was replaced with one that does not work (properly).

    Thanks for any info.
     
  9. Crater

    Crater

    Oct 12, 2011
    Dallas, TX area
    I believe the volume control pots for active EMGs is 25K ohms. If you used a 500K ohm or 250 K ohm pot instead, it probably would have full volume and then the volume would roll off quickly between 1 and 0 on the volume knob.
     
  10. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    Thanks Crater. That helps a lot. I appreciate it.

    This will be my first foray into replacing electronics on a bass. :bassist:
     
  11. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    Hello again, it's been a while.

    I'm getting ready to replace the faulty pot on my cort steinberger copy. I've been saving it as a summer project when I have down time. I may also end up painting the cort, but that's for another post.

    Looking over the wiring diagram that SGD Lutherie so kindly provided, I need the pot that is just left of the output jack. I assumed that this is a volume pot, and that the other 2 pots to the left of that where tone controls. The wiring diagram, however, lists the 2 pots to the left of the pot I need to replace as "volume".

    So then, are each of those knobs separate volume pots for each set of pickups, and the pot I have to replace (just left of the output jack) a tone pot? I ask because I need to figure out what to order.

    Also, if the pot I am replacing is then NOT a volume pot, does the 25K Ohms figure kindly provided by Crater still hold true, or would it have a different Ohms rating?
    Would this item be the correct one as a replacement?

    http://www.thomann.de/gr/gewa_emg_poti.htm

    I notice,too, that the pot I have to replace on the diagram there is a round resistor(?) or some such item connected to it, whereas this is not on the other 2 pots.
    Does that point out what kind of pot it is? None of the pots I've found as replacements seem to include this small part. Sorry for all the question. I'm new to this and trying to learn. All input is much appreciated.



    Thanks, in advance.

    Kon
     
  12. MPU

    MPU

    Sep 21, 2004
    Valkeala Finland
    The pot with the round "thing" is tone pot. If it is 25k that Gewa pot will work fine. You can use the old capasitor from the broken pot.
     
  13. That round thing is a capacitor for the tone pot. You'll need to solder that back onto the new pot. IIRC, you'll need a linear 25k pot for tone. 25k audio tapers for the volumes

    edit: Didn't notice the post above mine talk about the cap :p
     
  14. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    THanks MPU and ridethespiral. When I'm ready to get to work I'll let you all know if I have any more questions.

    ridethespiral, what does IIRC mean?
     
  15. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    I was just taking a look at the electronics in the bass. I notice that the wiring diagram above for the active EMG setup, which is what I have, does not show where to solder the ground wiring that goes from the underside of the bridge into the electronics cavity.

    It is currently soldered on to the back of the body of the tone pot (the one closes to the output jack). This is a replacement pot that someone installed years ago that never worked correctly.

    Any suggestions?
     
  16. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    Another point I've noticed:

    The jack on my bass has 2 "ears" (making it mono?), whereas in the wiring diagram for the active bass it has 3 "ears". I'm wondering if the jack was also replaced at some point.

    Seems like it's a mish-mash of items. Some of it adheres to the passive schematic and some to the active schematic. I is confused...Hodor....Hodor.
     
  17. Stealth

    Stealth

    Feb 5, 2008
    Zagreb, Croatia
    IIRC - If I Recall Correctly.

    Soldering it to the back of any of the pots will work. The pots' backs are all interconnected with the ground wire, and that in turn is connected to the ground lug on the output jack.

    It likely was replaced with a mono jack, which is okay for passive instruments but not good for active ones. Get yourself a stereo jack, which has 3 "ears" (lugs) instead.

    meh.ro11305.
     
  18. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    Thanks Stealth!

    Hodor, Hodor.
     
  19. You don't need to ground the bridge with active emgs
     
  20. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Queens, NY
    ridethespiral,

    Why do you think, then, there is a grounding wire coming from under the bridge into the electronics cavity?
     

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