I play on a Carvin 5 string bass with active pickups.

The other day while I was playing, my sound became suddenly very quiet and heavily distorted, until it eventually faded completely. I initially think "Okay, battery died, no big deal". I get some absolutely fresh 9V batteries and pop one in and still no sound.

So now my stomach is dropping, I decided to rule out some other obvious issues. I switch from my bass headphone amplifier to an actual cable and amp, still nothing. The last thing I did was remove the back panel and the output jack panel to look for obviously loose or detached cables, but there's nothing wrong that I can see. The output jack feels solid and is not loose.

My best guess would be that there is a problem getting power from the battery to the rest of the instrument. I feel like if it were a problem with pickups that one of them would probably still be functioning.

Potentially relevant information: I've played this bass for several years now, but acquired it used and the original owner had allowed the battery to corrode at one point. It has since been cleaned up at the shop, but perhaps that could cause lasting ramifications.

Obviously I could just take it in to the luthier, but what's the fun in that? I'm wondering if anyone has encountered this before or knows what's wrong. Maybe this is an obvious issue that I am just not familiar with. Any pointers?

  • 2
    This may sound silly but it’s gotten me before: if you didn’t take the battery out of the original packaging right before putting it in the bass, it could have been a battery you thought was fresh but wasn’t. If you’re not completely positive that it’s not the battery, it might make sense to go buy a brand new battery and try that just to be totally certain. Commented Feb 9, 2019 at 15:15
  • If there’s a small circuit board (i.e.: an onboard preamp), I wonder if a capacitor might’ve blown. :-? Commented Feb 9, 2019 at 18:25
  • @ToddWilcox Good suggestion but I actually went out and bought a fresh pack of 9V batteries because of this, so yes, definitely not the battery. (the extra I keep in my case didn't work so I thought it was dead) Commented Feb 9, 2019 at 18:48

2 Answers 2


A fairly common problem I've encountered is that the two little connections that go on the battery have parted company with the wires going to the circuit board. I check at the jack with a multimeter, and there should be best part of 10vdc there.


A fun failure mode for active pickup systems can be the use of a stereo QIC cable when the pickup "detects" the presence of a cable by shield and ring of a stereo QIC socket being shorted by a mono QIC plug. Depending on what you plug the cable into, this can just keep the pickup from getting powered.

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