Preamps that are true bypass?

Discussion in 'Pickups & Electronics [BG]' started by Axtman, Nov 28, 2012.


  1. Axtman

    Axtman Supporting Member

    Joined:
    Mar 3, 2008
    Location:
    Seattle, Washington
    Maybe I am not using the correct words "true bypass". You techies please correct me if I am wrong.

    I have had problems with the active electronics in my basses dying unexpectedly due to low battery.

    I love my Lakland 5501 bass but it died at practice last night. I know that by pulling up on the volume know the bass goes into passive mode. What I did not know is that you need a fully charged battery to do that! If you ask me, this kind of defeats the whole purpose active/passive switch.

    So what active electronic basses have true bypass?

    The way to test it is to remove the battery completely and see if you can still get a signal.

    Thanks!

    PS I read that Duff McKagan used to play a Power Jazz Bass Special until one night the battery died right before the big opening chord of the first song!
  2. Jazz Ad

    Jazz Ad Mi la ré sol Gold Supporting Member

    Joined:
    Mar 16, 2002
    Location:
    Reims, Champagne, France
    Very surprisingly, MusicMan basses work without batteries, although the signal you get is very low.
  3. line6man

    line6man

    Joined:
    Jun 20, 2008
    Location:
    Close to Los Angeles, CA
    Active/passive switching is usually done independent of the preamp. The only time it's not possible is when the preamp has multiple inputs, thus requiring complex switching to wire in a passive configuration; or when the preamp has PCB mount components that make it difficult to modify any wiring.
  4. mcnach

    mcnach

    Joined:
    Jun 16, 2007
    Location:
    Edinburgh, Scotland
    ?
    I have a Stingray with a bypass switch fitted, it's just as loud in either position.

    Edit: Oh, you mean a standard Stingray without battery at all? I never tried that!
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  6. DWBass

    DWBass The Funkfather Supporting Member

    Joined:
    Jan 24, 2003
    Location:
    Newport News, VA via NYC
    Disclosures:
    Kohlman Bassworks
    I have a 55-01 which I replaced the stock pre with a US Bartolini 5.2AP preamp which is true bypass. If the battery dies, just pull up on the volume knob and you're back in business!
  7. macribas

    macribas Supporting Member

    Joined:
    Jan 17, 2009
    Location:
    Austin, TX
    Sorry you had to find out the hard way. The MK-1 preamp in the 01 series does not have a passive mode. It's well documented. What happens when you pull the switch is that it only bypasses the EQ, but it is still active. If your battery dies, you are bassless.
    That and the hideous hissing are the reasons why the first thing most people do when they buy a 01 is to swap the preamp. The most common choice is the Bart 5.2 AP (as mentioned),
  8. DWBass

    DWBass The Funkfather Supporting Member

    Joined:
    Jan 24, 2003
    Location:
    Newport News, VA via NYC
    Disclosures:
    Kohlman Bassworks
  9. Axtman

    Axtman Supporting Member

    Joined:
    Mar 3, 2008
    Location:
    Seattle, Washington
    Thanks guys for the suggestions.

    So back to my original question:
    I think that the following basses have true bypass:
    Musicman
    G&L
    Carvin

    Is this correct?

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