Active bass players - pre-gig battery tester?

Discussion in 'Basses [BG]' started by C_Flat, Jul 17, 2003.

  1. C_Flat


    Jan 29, 2001
    I figured this would be easier for me to post here than to test it for myself:

    I always unplug my Jazz Bass Deluxe after playing to avoid draining the 9 volt battery. The thought just occurred to me that it might (should?) be possible to test the state of the battery via the bass' input jack. If I rigged up a 1/4" mono plug to a 9 volt "battery clip" could I test the battery as it sits inside the bass using my cheapo tuner with the little battery charge indicator?

    I'm thinking I could simply stick the 1/4" plug into the bass input jack, and attached the 9V clip to the tuner's battery clip to get a reading. Think that'd work rather than pulling the battery out of the bass?


  2. no. it wont.

    the plug is just a trigger for turning it on or off.
  3. garron


    Jun 26, 2003
    DC area
    I've never tried it on my J-dlx. Depending on how much it is played, the safest bet would be to change them at least every other week. When I am playing and especially gigging frequently, then I change them once a week. This way, I never have to worry about not having the juice when I need it!
  4. bikeplate

    bikeplate Supporting Member

    Jun 7, 2001
    Upstate NY

    If you unplug your active bass when not playing it, a battery should last you a few months, not a week. I have pre's in all my basses and change maybe twice a year

  5. Wrong Robot

    Wrong Robot Guest

    Apr 8, 2002
    If it is that much of an issue to you, perhaps you should consider getting a standby switch installed on your bass.
  6. ConU


    Mar 5, 2003
    La Belle Province
    I use my tongue to check every few months or so,takes about 10 seconds.
  7. DanGouge


    May 25, 2000
    bikeplate is right. My batteries last forever, I change 'em twice a year, like a smoke detector...
  8. Yeah, and that'll be really funny when you're 60 and have lost control of your ability to speak or taste food.
  9. slapphappy


    Jul 7, 2003
    NW Ohio
    yes, in fact this will work. You can also supply 9v DC to an active instrument with an isolated 9v DC source at the other end of a cord, just like phantom power for an active microphone. There was an amp manufacturer that did this, but I can't remember who. The tip of the 1/4" plug will be positive, and the sleeve will be negative.

    Your batteries should last you 6 months or so, even if you play a lot. If they are draining faster than that, you may look for a short in the controls cavity. This would usually be accompanied by godaweful sounds as well.

    Good luck!
  10. PhilMan99


    Jul 18, 2003
    US, Maryland
    In general, you can't just connect a battery-tester to a 1/4" stereo plug, and plug it into your bass. The problem is that the both sides of the battery are not connected to the 1/4" stereo plug - only 1 is. The rest of the pre-amp circuit has to be passed through. This is unfortunate, because a battery tester does a good job by placing a load on the battery - when connected directly to both terminals!

    A good comprimise was published in one of the major bass/guitar rags in the past. Connect a volt-meter to a 1/4" STEREO plug (to "Ring" and "Sleve" if I recall, but check carefully), then plug it into your bass to measure voltage (V). Sadly, this does not load the battery much (just the preamp load), but it's still a pretty good check. I also check the current (mA), comparing with what I get with a known good battery.

    As other posters indicate, batteries should last a long time (many, many months) if you unplug when not playing.
  11. rickreyn


    Jun 16, 2000
    Lutz, Florida
    Unless you're playing a Cirrus, the batteries should keep going, and going, and going...if you unplug your bass.

    My former Cirrus used more batteries than my old VW did oil.
  12. superphat


    Sep 30, 2001
    i keep my bass unplugged, but the batteries die after around 4-6 months or so... (aguilar obp3 18v)

    but i noticed that the tone changes noticeably when the batteries are not fresh. so i change my batteries every 2-3 months.

    if you feel the need to test the batteries, then chances are pretty good that you need to change them!
  13. Mike A

    Mike A

    Oct 3, 2002
    I also use the good ol' tongue check method, but if there's any doubt at all, or if the battery's been in there for any length of time, I'll swap it out before any important gig, just in case. Old batteries get demoted to pedals, tuners, junk around the house, etc.
  14. HeavyDuty

    HeavyDuty Supporting Curmudgeon Staff Member Gold Supporting Member

    Jun 26, 2000
    Central Texas
  15. brock29609

    brock29609 4 strings, 2 wheels

    May 11, 2003
    Greenville, SC
    Do what I did. By a pair of rechargeable NiMH batteries and a charger. Keep one in your bass and one in the charger at all times. After about a dozen gigs, put the fresh one in your bass and put the old one in the charger. Just keep swapping back and forth. Each battery is supposed to last for 500 charges.

    Don't buy them at Radio Shack. Overprices. Lots of good online retailers. I got my whole order (2 9V batteries and charger) shipped for $20.