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Why Don't They Ever......

Discussion in 'Pickups & Electronics [BG]' started by ZenG, Jan 1, 2014.

  1. ZenG


    Dec 13, 2013
    Near the fridge
    Put an on/off pre-amp switch on bass guitars?

    If they do I haven't as yet seen one in my travels....

    I know they make pre-amp "bypass" switch but I'm thinking if the makers know that your battery goes low if you leave it connected to the cable......wouldn't a switch solve the problem?

    Especially for people playing gigs......where if they leave their bass plugged in for the entire gig, they are using up a lot of battery juice for nothing....

    But it would be a nuisance having to unplug your cable at every break etc.

    Or stopping to have to change a battery mid-gig.....
  2. The first one of 2014........
  3. ZenG


    Dec 13, 2013
    Near the fridge
    First what?
  4. BBox Bass

    BBox Bass Supporting Member

    Apr 2, 2011
    NW Pennsylvania
    Peavey did it on the Dyna-Bass way back in the 1980s.
  5. SactoBass

    SactoBass There are some who call me.......Sactobass Supporting Member

    Jul 8, 2009
    Sacramento CA
    I think that such a switch might be helpful. I would imagine you would need to turn the volume on your amp to zero before flicking the switch on, otherwise you might get a loud "pop".
  6. 20db pad

    20db pad

    Feb 11, 2003
    I been everywhere, man...
    None. At all.
    Lots of builders have and still do. Most use push/pull pot switches now.
  7. ZenG


    Dec 13, 2013
    Near the fridge
    I don't see the "push pull" pre-amp switch mentioned at all

    on the last 15 bassmaker sites I've visited.....l
  8. smeet

    smeet Gold Supporting Member

    Nov 27, 2006
    Woodland Hills, CA
    The push-pull goes into passive mode, but the battery is still being drained.
  9. 20db pad

    20db pad

    Feb 11, 2003
    I been everywhere, man...
    None. At all.
    You're probably right...
  10. BawanaRik


    Mar 6, 2012
    New Jersey
    Most manufacturers do. The preamp power uses a TRS jack that sends power when it has a plug in it.

    As to why a more elaborate system isn't in place. Money. Everything on a bass cost money.

    If you talented enough you can get a pot with a push pull switch to break ground.

    It would be much easier to get a volume pedal turn it to off and remove the plug.

    Or ignore the battery drain since they tend to last months anyhow. Too be uber cool install colored LEDs that display battery strength. That way you'll know when to change them.

    Organolyptic testing of a battery is quick and with a bit of practice can be pretty darn accurate.
  11. ZenG


    Dec 13, 2013
    Near the fridge
    I realize that the preamp is turned on when you plug the cable in the guitar

    and also that it is switched off when you unplug the cable

    but rather than unplug/plug the cable I'd prefer a simple onboard switch that does that......

    My SR500 doesn't come with such a switch.....but I wish it did
  12. JTE


    Mar 12, 2008
    Central Illinois, USA
    An extra hole drilled into the wood, an extra switch to source, a bit more wiring required (done by hand in most cases, therefore more money), and another component that's subject to being broken in use and possible warranty issues for something that's not that important to most people. I've used active basses since 1978 and only ONCE has a battery problem impacted me on stage- and that was due to the battery NOT being a Duracell, not because of it being drained too much. I change batteries in my basses once a year and even on the pre-EB StingRays (where the battery was never switched out of the circuit) have I had a problem. It's a much over-thought problem by people without either experience using active instruments or with improperly wired instruments.

    Plus, switching the pre-amp off will generally result in a transient into the system, causing at least a loud "pop" and possibly damaging the amp.

    Just mute the signal and unplug if you're paranoid about battery use. Or leave it plugged in and use a simple multi-meter to measure the voltage across the battery while it's in the instrument once a week.

  13. wvbass


    Mar 1, 2004
    Please don't make me look up big words that you spelled incorrectly. Just say "put your tongue on it." Then say "that's what she said."

    Nobody puts a switch like this in a bass because it doesn't make any sense. Instead of forgetting to unplug a cable, you'd just forget to flip the switch. The battery goes dead either way.
  14. Because on/off switches cause pops and DC offsets. Also, they are pointless. Current consumption is very low, and it's not a terrible inconvenience to unplug a bass.

    If you consider a milliWatt or less to be a lot of juice, then yes. The current consumption of most preamps between tens of microAmps at the lowest and a milliAmp or two at the highest.
  15. If you are concerned about draining batteries or dead batteries in landfills, you can power your internal preamp from a wallwart instead. All it takes is a stereo (TRS) instrument cable, a reversible wiring mod to your battery clip, a wallwart, and an external box which allows you to feed the wallwart power to the preamp through the stereo instrument cable while feeding the signal to a mono instrument cable to the amp.
  16. Savage_Dreams


    Jan 8, 2007
    is it really that hard to unplug your instrument? i never leave it plugged in when its not on me anyways even though mine are passive. what if someone walks by it and catches the cord on their foot? boom...one bass falling to the floor.
  17. +10

    Leaving your instrument plugged in is inviting trouble. Sooner or later, trouble will accept that invitation.


    Always, active or passive.
  18. wcriley


    Apr 5, 2010
    Western PA
    Hmmmm....Maybe that's why so many manufacturers put the jack right where the arm is on so many stands.
  19. Staccato

    Staccato Low End Advocate

    Aug 14, 2009
    +1 on my Dynabass, too! The cable gets disconnected after practice, and the battery seems to last forever. In fact, I usually replace it after a year anyway-just for fun. :bassist:
  20. mech

    mech Supporting Member

    Jun 20, 2008
    Meridian, MS, USA
    ^^^^^This....most preamps will go unstable and make strange sounds as the power supply drains. Most quality preamps have a storage capacitor that buffers the supply and helps with transient loads and will take a time period to discharge. Coupling capacitors, if there are any, must also discharge when the supply is removed. It's best that the output is muted or disconnected when this happens although it doesn't damage the preamp. Bipolar supply preamps (+/- 9V) are more susceptible since one side may discharge before the other and this can cause instabilities in the gain stages. If you would like to see how your preamp acts, disconnect and then reconnect the battery while the bass is plugged into an amp. BE SURE TO HAVE THE VOLUME TURNED WAY DOWN.

    It can take as much circuitry to make a preamp turn off gracefully when the supply is removed than it takes for the preamp itself.