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Can I kill my internal electronics inverting power polarity?

Discussion in 'Pickups & Electronics [BG]' started by pepechin, Oct 21, 2013.

  1. pepechin


    Jan 6, 2004

    I had a Ibanez BTB that wasted a battery every other day (don't ask me why, I don't know)

    So I modified it some years ago, installing a 9V power supply inside my Cube amplifier and powering the internal electronics via a custom made XLR cable and connections.

    After long time without playing, I changed that to send the bass for some luthier adjustment. When installing again all the wire I think I inverted the power supply polarity.

    Now there's no sound from bass, neither with internal 9v battery and standard jack connection.

    Maybe I have burned internal electronics?
    Is 9V enough to do that?

  2. Yeah, you can destroy components that way.
  3. pepechin


    Jan 6, 2004
    I feared I'll have to spend some money on that....

    I'm pretty sure the preamp would be death, but also the pickups?
  4. Crater


    Oct 12, 2011
    Dallas, TX area
    The pickups should be fine. In fact, the power supply voltage should never make it to the pickups.
  5. pepechin


    Jan 6, 2004
    Thanks for the answers

    Now I'm going to try to find parts replacement....
  6. If the preamp is not epoxy-potted, try replacing the Opamp, or FETs.
  7. pepechin


    Jan 6, 2004
    I'm afraid its all encapsulated in a plastic brick

  8. thats a really incredible solution you came up with for what was most likely a grounded negative lead or a miswired jack.
  9. pepechin


    Jan 6, 2004
    That's the same the luthier told me :D

    I have always been a solder lover and a little prone to over-engineering
  10. Although many 9v powered devices are immune to this kind of damage it seems your piece unfortunately isn't.
  11. iiipopes

    iiipopes Supporting Member

    May 4, 2009
    Some of the newer designs have diodes from the battery to the preamp to prevent voltage from leaking through and damaging the preamp. If you think it is already dead, then it wouldn't hurt to reverse it again to see if this is the case. If the diodes are there, they would block all voltage and the preamp would have zero output.
  12. bassbenj


    Aug 11, 2009
    Yes, all 9 volt battery devices SHOULD have diodes, but unfortunately some don't. Obviously it's really easy to put the battery in backwards and touch the wrong terminals reversing the voltage even though it won't snap in place. I trashed one of my G&Ls this way. It burned out the integrated circuit (bug). It wasn't potted and the ICs are cheap (little over a dollar). I put in an IC socket for next time.

    So yes, do try it back wired right and see if you got lucky if not, just remember the rule:

    Transistors make better fuses than fuses. :)

    By the way, I now power most of my basses over a TRS stereo cable from the amps. Just use a one-spot inside the amp. Works just great. for most basses all you have to do is short the battery clip and it works since the battery negative usually goes to the "ring" contact. No special connectors needed. Cool thing is it lets you install all kind of "current hog" things like neck marker LEDs. And should your power supply die, you can always unclip the battery short and put the bass back to battery operation. I wire it so all "current hogs" only work from the supply and not from the battery.
  13. pepechin


    Jan 6, 2004
    Your's a much better solution than mine. I use a 4 pin XLR with separate wire for signal and suply (I tried to have no noise)

    My solution is incompatible with any standard cable and connection that's the reason of the disaster
  14. mrbell321


    Mar 26, 2012
    N. Colorado
    So, it's probably a polarized capacitor that blew. Transistors and op-amps aren't typically too polarity sensitive.

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