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Frugal Batteries

Discussion in 'Hardware, Setup & Repair [BG]' started by gumwr, Jan 21, 2003.


  1. gumwr

    gumwr

    Jun 3, 2002
    Harrisonburg, Va
    i have a bass with passive EMG's and an active Bartolini NTBT eq. i'd love to think that i am not the only one out there who wants to save bucks on batteries and also doesnt want to unplug his bass everytime he's done playing it. in that light, how would one go about wiring in an active passive switch that would turn off the battery power when the bass is switched to passive and still plugged in? thanks

    william gum
     
  2. You could put a SPST throw switch in series with the active (red) wire coming from the battery...

    maybe??

    :D:D

    Merls
     
  3. gumwr

    gumwr

    Jun 3, 2002
    Harrisonburg, Va
    this is true, but it would add a switch to the assembly.... dont want to do that. what i would need is a switch that simultaniously by-passes the preamp AND cuts the power supply. passive doesnt need the juice, but the current is still flowing because of the stereo jack being plugged in. maybe a special switch can do this?

    william
     
  4. In active basses the jack is the switch really. So you'd have to find a spot to break the circuit for a switch to disconnect the supply, and also find a second spot to disengage the whole active process. a DPST switch would do the trick but where in the circuit i do not know. Maybe Notduane can come up with a diagram...... ;)

    :D:D

    Merls
     
  5. notduane

    notduane

    Nov 24, 2000
    Location
    hmm...maybe if I wasn't on call this week workin' 12 hour days [​IMG] :p

    I think Unky Merls is on the right track, i.e, put a switch in series
    with the ground line comin' off the jack (the one goin' to the black
    battery lead).

    I was thinkin' maybe replace one of your controls with a
    push-push control pot -- a 250KΩ or 500KΩ with a DPDT
    switch attached.

    Use one side of the DPDT to switch the battery negative lead,
    and the other side to bypass the preamp.

    What you'd get with one action == battery connected and the
    preamp in circuit...(push) == battery disconnected, preamp out
    of the circuit.
     
  6. Thats a good idea. Save drilling another hole. ;)

    Hmm maybe if there was a circuit diagram of this setup.... *rubs chin*

    Any Thoughts Pkr2??

    :D:D

    Merls
     
  7. pkr2

    pkr2

    Apr 28, 2000
    coastal N.C.
    Seems that ND has hit the proverbial nail on the head, as usual.

    We need to see about getting him on the payroll. He's a valuable person to have on call. :)

    Pkr2
     
  8. Dont mention to Notduane about being on call... hehehee We know he loves being on call.. ;)

    :D:D

    Merls
     
  9. fclefgeoff

    fclefgeoff Supporting Member

    Jan 3, 2002
    Illinoize
    Why is it so difficult to unplug the bass when you're not playing it? :rolleyes:
     
  10. notduane

    notduane

    Nov 24, 2000
    Location
    well...I stroked my beard o' magic™ :eek::p and it came up with `dis `ere --

    http://www.glguitars.com/schematics/

    IIRC, one of these G&L pdf (sorry :( ) diagrams shows a
    active-passive wiring scheme.
     
  11. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    If you switch the power to the preamp off and on with the bass plugged in and your amp on, you are going to get a nasty loud pop. (Just like is sounds when you plug in the cable with the amp on)

    This certainly isn't the best for the long life of your rig. Not to mention a sound guy's worst nightmare and generally annoying.


    Chas
     
  12. pkr2

    pkr2

    Apr 28, 2000
    coastal N.C.
    You are probably right Chas. It would be easy enough to verify if this would be a problem. Just connect and disconnect the battery and see if it pops. If it does, a cap of the right value across the B+ should tame it down.

    Pkr2
     

  13. Would this bring into the horrid concept of Tim Constants (charging times?) You'd need to experiment with various values, possibly in the 100's of microfarads huh? Electrolytic or are they too noisy?

    Hmm design questions ARG!

    :D:D

    Merls
     
  14. pkr2

    pkr2

    Apr 28, 2000
    coastal N.C.
    No, all you are trying to accomplish is to round off the leading edge of a square wave. The value wouldn't be very critical. In the MFD. range, probably.

    Pkr2
     
  15. Brooks

    Brooks

    Apr 4, 2000
    Middle East
    Hmmm...a lot of solutions for what is basically a non-existent problem. It is much easier just to unplug the bass, not to mention that it is safer. I've seen too many people trip up on a cable and take a guitar (or bass) down with it. Just my opinion...
     
  16. pkr2

    pkr2

    Apr 28, 2000
    coastal N.C.

    It's kind of hard to explain, Brooks.

    Everyone in the discussion is pretty much aware that William probably wont actually make the mods that we are discussing.

    Tech heads just enjoy talking electronics. Kind of like musicians enjoy talking about music.:)

    If I weren't into electronics, I would probably just skip over a thread like this one.

    Different strokes for different folks, as they say. :)

    Pkr2
     
  17. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    Here's an easy solution. Buy a 9v ac adapter that has the battery clip ending and a long lead. Clip it to your bass' battery terminal, most adapter leads are thin and will squoosh in between the compartment and the cover. If you do not like dealing w/ 2 cables (signal and 9v power), buy a wireless (make sure the beltpack has an on/off swith) to take care of your signal.

    Or just unplug your bass.

    Or buy a passive bass.

    Or replace your active pre w/ a passive one.

    Or bypass your pre altogether.

    Or sink some $ into R&D and develop a 9v DC fission reactor that fits in your battery compartment.

    :rolleyes: :D
     
  18. Chasarms

    Chasarms Casual Observer

    May 24, 2001
    Bettendorf, IA USA
    Actually, you just need to change your input to XLR and shoot phantom power into the bass to drive the preamp.

    Chas
     
  19. fclefgeoff

    fclefgeoff Supporting Member

    Jan 3, 2002
    Illinoize
    That would be AWESOME. Anyone know where I can get a 48 volt onboard preamp for a 1997 Fender American Deluxe P-Bass?
     
  20. Sure but where wouldu get the 48 volts from and then go into your amp. You cant apply 48 volts to the input of your amp...And say if you made a Y type cable, you'd have to make sure one ALWAYS went to the 48 supply..

    :D:D

    Merls