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Active bass with no preamp?

Discussion in 'Pickups & Electronics [BG]' started by AlexMC, Apr 14, 2018.


  1. AlexMC

    AlexMC

    Apr 14, 2018
    I've just purchased a used 'Vester Clipper' active bass (Warwick thumb copy) from eBay; I'm no expert but it looks like the previous owner has messed with the electronics (photos attached):

    - a 9V battery is installed: positive -> both pickups; negative -> output jack ground lug
    - no preamp in the control cavity
    - neck p/u output -> wiper on vol pot #1 (B50k)
    - bridge p/u output -> wiper on vol pot #2 (B50k)
    - pot #1 and #2 outputs -> wiper on tone pot (B50k) with a parallel connection to the output jack
    - there is no evidence (screw holes etc) that a preamp was ever present in the cavity

    Does this configuration makes sense (I thought that an active bass always needed a preamp)? If not, I guess I need a preamp suitable for 2 J pickups and 3 control knobs. I'm assuming there are several possible configurations such as:

    - neck volume, bridge volume, concentric bass/treble
    - concentric neck/bridge volume, bass, treble
    - master volume, blend, concentric bass/treble

    There is no room for an extra mid pot but I could drill a hole for a mid-cut toggle switch if the preamp allows it.

    Please help!
     

    Attached Files:

  2. MPU

    MPU

    Sep 21, 2004
    Valkeala Finland
    Looks like it has active pickups. Which brand are the pickups?
     
  3. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    If it sounds fine the way it is you don't need to add a preamp.
    Active basses normally have passive pickups & the active part is the preamp.
    You've got the opposite, active pickups & no preamp.

    EQ it the old-fashioned way, by blending in as much of the bridge pickup as you like for treble, or as much of the neck pickup for bass.
     
  4. AlexMC

    AlexMC

    Apr 14, 2018
    They are marked Vester HB-III but appear to be single coils.

    Is the configuration I've described typical or would I need/benefit from a preamp? View attachment 2984014

    Its a well built instrument with brass nut, 5 piece neck, locking bridge and great upper fret access and is in amazing condition, so I want to keep it if I don't have to spend too much on upgrades.
     
    Last edited: Apr 14, 2018
  5. mech

    mech

    Jun 20, 2008
    Meridian, MS, USA
    @AlexMC .....Active pickups do not require a preamp and your bass was built with no preamp. The wiring is conventional for a two pickup bass and if you like the way it sounds there's no need to change anything. Be sure to unplug the cord from the bass when not in use to save battery life.
     
    Conkal, pudgychef and Killed_by_Death like this.
  6. NOVAX

    NOVAX

    Feb 7, 2009
    Kalifornia
    Yes. I have 2.
     
  7. AlexMC

    AlexMC

    Apr 14, 2018
    Thanks for the advice!

    When correctly intonated, the silk wrap at the ball ends extended slightly over the bridge saddles - which I presume sucked some treble - and it was strung with nickle rather than the stainless steels I'm used to; it just sounded dead with no presence both unplugged and plugged in; I've ordered some D'Addario ProSteels (which have no silk wrap at the ball end) and HOPE that they will give me the tone I'm looking for.

    I have a good understanding how passive pickups and circuits work, but can anyone explain how the 9V battery is hooked up to the pickup and the benefits of active pickups over a completely passive setup?

    Secondly, if I wanted more control of my tone could I add a preamp whilst retaining the existing pickups?
     
  8. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    The major disadvantage of single coil passive pickups is that they pick up noise, because of all the coils of wire act like an antenna for EMI.
    Active pickups have less coils of wire, lower impedance, & less induced noise.
    The battery is for the internal preamp, to amplify the weaker signal provided by fewer coils.
     
    Spectre Gunner and mech like this.
  9. FilTurd

    FilTurd

    Dec 13, 2015
    Pacific Northwest
    I know your question is answered but my Guild had Active w/o a pre amp and it is and was the greatest sound I've had the opportunity to use in a 30 year period
     
  10. InhumanResource

    InhumanResource

    Dec 28, 2012
    Active pickups already HAVE a preamp. It's just inside the pickup housing and has no controls for EQ. Whatever it is voiced to is what you get.
     
    mikewalker likes this.
  11. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    Fishman has been making pickups with different voicing within the same pickup. It's a brilliant idea that should have been come up with a long time ago:

    Fluence Open Core Classic Humbucker Pickups | Fishman

    Maybe one day someone will make them this way for bass guitars.
     
  12. AdamR

    AdamR Supporting Member

    Sep 24, 2007
    Bethel CT
    That bass is passive. Passive pick ups, no pre amp. You can have active pick ups with out an active preamp. EMGs and all active pickups have a preamp built in. You can also run passive pick ups with an active pre. But that bass is totally passive.
     
  13. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    If it can't function w/o a battery, it's active.
     
    96tbird, hintz, dralionux and 3 others like this.
  14. ctmullins

    ctmullins fueled by beer and coconut Gold Supporting Member

    Apr 18, 2008
    MS Gulf Coast
    I'm highly opinionated and extremely self-assured
    :meh:

    Then what’s under the small black cover, and what do the red wires connect to?
     
    96tbird, wmhill and Killed_by_Death like this.
  15. Yup! ^ This...
    If he hadn't, I woulda.

    So take out the battery see if it plays.
    Put the battery back in see if it plays.
    If the results are NO and YES you're all good. (Assuming a good battery and no other issues.)

    And yes Virginia, it is possible that the actives are built into the pickups. In that case you don't see the usual actives (pre-amp) in the control cavity.
    The 50K pots also a give-a-way to being active. 50K is awful low to be using with passive pickups.
     
    Last edited: Apr 14, 2018
    dralionux, mcnach, pudgychef and 3 others like this.
  16. gumtown

    gumtown

    May 7, 2007
    New Zealand
    One of my 30 year old basses has EMG active pickups, the preamp is built inside the pickups.
     
    ghostinthemach likes this.
  17. Abner

    Abner

    Jan 2, 2011
    Mississauga
    Seymour Duncan used to make active pickups with DIP switches on the top, so you could change the eq. So I guess somebody did come up with it a long time ago. ;)
     
    Zoobiedood and themarshall like this.
  18. pudgychef

    pudgychef In Memoriam

    Jan 22, 2005
    Chongqing, China
    Make sure you pop in a new battery as well, if you haven't....no knowing how long it has been in there if it came with the bass
     
  19. nilorius

    nilorius Inactive

    Oct 27, 2016
    Riga - Latvia
    You have an active pickups, just keep on with the battery. And the active electronics will not give you that much of extasy to be wourth messing with it. Also remember that automaticaly the electronics will take half of the battery enenergy.
     
  20. gumtown

    gumtown

    May 7, 2007
    New Zealand
    Just don't leave your bass laying around for a week + with a lead plugged into, or you will find the battery has gone dead.
     
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Apr 11, 2021

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