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2 active basses, major output difference

Discussion in 'Pickups & Electronics [BG]' started by cdaniel, Oct 31, 2010.

  1. cdaniel


    Nov 29, 2003
    Looking for help with my dilemma. I have two Deluxe Fenders that I love and use to gig regularly. One Jazz 9v and one Precision 18v. With my amp set for the J bass and switching to the P, it becomes very over driven. Resetting on the fly during a show is problematic because we run sound from the stage. Keeping a similar level in the mix after changing the amp is difficult.

    To even them out, is there any mod to a bass I could do? Or a device I could use in line?

    Is it as simplistic as pulling one of the batteries out of the 18v bass?
  2. Samsound


    Sep 28, 2010
    Have you tried the Vol knob on the bass? Or does that alter the sound too much?
  3. cdaniel


    Nov 29, 2003
    What a novel and helpful idea.

    Simplistic yet sarcastic in it's entirety.

    Thank you so much for this insite.
  4. Turning down the volume on an active bass shouldnt change the tone like it does on a passive bass! Why dont you just turn down?
  5. Samsound


    Sep 28, 2010
    I wasn't being sarcastic. I asked if it had undesirable side effects. It's as valid a solution as pulling batteries or some other attenuation method.

    Oh, you're right, you should build a custom resistor bank, mount it in a box with a detection circuit that can detect the 18v bass and switch on automatically. Makes way more sense than a stupid volume knob.

    Now that was sarcastic.
  6. cdaniel


    Nov 29, 2003
    Okay, I would prefer to keep the volume at max on both basses. I do turn down the P bass, but that pot is easily bumped out of position. Finding the original setting after a bump is a problem. No position markers on the knob.
  7. cdaniel


    Nov 29, 2003
    Yes, yes that was. And if your original reply wasn't then I apologize for the reaction.

    Please see my subsequent response to the knob in question.
  8. drewfunk


    May 10, 2010
    Olympia, Wa
    Position marker = black dot on knob from a sharpie.
  9. Samsound


    Sep 28, 2010
    I believe there's a certain type of washer you can get that makes the pot detented. Add s knob with numbers, and it might be less headache and expense than modding the electronics.
  10. Samsound


    Sep 28, 2010
    But, if you're bent on modding the electronics, then you could probably throw a resistor of some value in there either after the volume pot or before the output jack - maybe a trimpot, so you could fine tune the attenuation.

    Another option is a volume pedal. Some models let you set min and max volumes.
  11. FunkMetalBass


    Aug 5, 2005
    Phoenix, Arizona 85029
    Endorsing Artist: J.C. Basses
    Have you tried lowering the pickups on the P-bass and raising the jazz pickups?

    Chances are, the pickupns on the P-bass are just inherently much hotter than the jazz. Also, due to string vibrations and pickup tonality, they can easily sound louder than the jazz pickups through the same amp EQ settings.

    The other option, as mentioned, is to install a trimpot before the output jack to adjust the volume level.
  12. Jefenator

    Jefenator Supporting Member

    Aug 22, 2008
    Since 18V requires two 9Vs wired in series, pulling one battery will interrupt your power supply. (Actually, removing one battery from each bass would pretty much guarantee identical output. ;))

    Converting to 9V would be slightly more involved and might affect headroom more than gain.

    I would get a 25K trim pot and wire it up like a volume control in the cavity of the louder bass (insert AFTER the preamp). Set that to match your other axe, button 'er back up and you're good to go. (An old Bartolini preamp I had came this way - very handy.)
  13. darkstorm


    Oct 13, 2009
    A mod you can do? yes. Replace the preamp in one with the one thats in the other. Then both have same preamp and thus pretty much same output level that just varies a little depending on the diff pups. Seriously if had this sitauation it and replaceing one of the basses would be the only options Id concider. Just cant get on with haveing two with that much diff between them myself.
  14. Marton


    Sep 20, 2005
    A/B box with volume settings on it ?
  15. FunkMetalBass


    Aug 5, 2005
    Phoenix, Arizona 85029
    Endorsing Artist: J.C. Basses
    You'd replace a bass that you liked instead of doing a $5 mod?
  16. cdaniel


    Nov 29, 2003
    Several good suggestions.

    I have lowered the pickups on the P-bass, but only to be out of finger range, I dig in a lot. Didn't seem to effect the volume though.

    I looked for a detent washer a little. No luck yet. I did find a washer with an external tab you can use with a numbered knob. doable, but I'd rather keep the look of the original knobs.

    The internal trim pot idea sounds doable too. Anyone have a parts list and wiring diagram. I'm no sparky, but I can solder and follow instructions.

    The A/B box is something I tried. The trouble is I use a wireless live and switch it between guitars. So I had to split the signal for volume and recombine it to feed the amp. The gear i found was noisy and too much extra stuff to fool with.

    Same for a volume pedal, another thing to trip over or fail.

    What would be a worthwhile pre amp upgrade for both basses?
  17. lowendgenerator


    Mar 26, 2006
    Correct me if I'm wrong, oh wise TB crewe, but wouldnt jumping the positive and negative leads off of one of the two 9v connections in the P still allow 9v of current to power the preamp? If so, go to Radio Shack and buy a 9v battery conector, solder the ends together, and snap it in place.
  18. Samsound


    Sep 28, 2010
  19. TwinBass


    Oct 5, 2007
    Spokane, WA
    Does your amp have an active/passive switch for the input, or two different inputs perhaps? It might be worth a shot to see if the volume difference in the two inputs/input settings would solve your problem. Sometimes it's the simple option.

    Good luck. :)

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