What exactly is the difference between Active/Passive?

Discussion in 'Basses [BG]' started by cordova, Feb 1, 2002.

  1. cordova


    Oct 24, 2001
    I'm really unsure of what the difference is between active and passive pickups. From what I understand (and for all I know, I'm dead wrong) is that active uses some sort of electronics to modify the tone in some way, and passive is just the natural sound of the bass.

    Could someone please explain the difference to me? I'm really confused.
  2. If I'm not mistaken, active PUs must have power (from a battery) to make them oprerate. Passive PUs operate without a battery and generally have lower output. I have a bass with passive PUs and an active preamp. That bass can operate with the active preamp engaged or without it if the battery dies in the preamp.

    Hope that helps,
  3. Mik Walker

    Mik Walker Supporting Member

    Dec 26, 1999
    That's pretty much it. Active basses feature electronics that require power to make them work. Usually this is in the form of a 9-volt battery, but can be 2 or more depending on the system.
    (Status make a 36-volt Hellborg Signature bass and Alembic provide external power supplies to drive their hungry Series basses for example).

    Some active circuits run multiple batteries in parallel to get a higher capacity 9-volt supply, some in series to get larger rail voltages which, in a good design, translates to greater headroom in the instrument's onboard amplifier - Generally the active part of the electronics is the preamp or tone and volume section of the instrument. This allows you to "actively" boost frequencies as well as cut them, providing you with much more tonal variation and control than passive basses. Another generalisation is that active basses deliver a substantially higher output level than passive basses - one reason why bass amps and preamps often feature two inputs these days, to easily match active and passive instrument signals.

    There are some very clever active systems out there - the Wal, for example, has many neat features including an onboard DI, complete with balanced XLR output for feeding directly into a mixing board mic preamp.

    Most active systems actually comprise passive pickups with active preamp electronics.

    Passive basses do not require power for their preamps. The tone shaping provided by such basses is passive and therefore only allows you to passively filter out or roll off higher frequencies. There is no way to boost.

    Hope this helps somewhat.

  4. cordova


    Oct 24, 2001
    Thanks guys, that clears it up nicely!