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How to differentiate active from passive pups?

Discussion in 'Pickups & Electronics [BG]' started by ny_chan, Aug 8, 2005.


  1. I have a Yamaha P-J bass. It is an active bass. Don't know if the pups are passive with active preamp or just active pups. How do you tell them apart.

    Thinking of changing the J as it is annoyingly noisy! Don't really like single coil hums, no matter how soft!

    Didn't know better. Back then just started playing bass.... :rolleyes:
     
  2. Trevorus

    Trevorus

    Oct 18, 2002
    Urbana, IL
    most likely passive pickups with active electronics. you can check to see if there is 3 leads going to the pickup, with one hooked to the battery in some way.
     
  3. If there are 3 leads, with one hooked to the battery then is active? or passive? :confused:
     
  4. Trevorus

    Trevorus

    Oct 18, 2002
    Urbana, IL
    It's active if the pickups are hooked to the battery. There will be a common ground for everything , which is the negative side; but what you are looking for is for the pickups to be hooked up to the positive side of the battery.
     
  5. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    Active, in other words taking power from the battery.
     
  6. my pups have 3 leads. Green, white & black. The Green and Black is going to a common ground and the Whites are going into the balancer.

    Maybe the green is for grounding the cavities? Where the pups recesses.

    The battery's + is going into the circuit board for both bass & treble tone.

    The bass and treble pots are getting their signal from the volume pot alone.
     
  7. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    yeah, some passive pickups have an additional ground wire from shielding in the pickup. Sounds like that's what you have
     
  8. Isn't this just a technical difference of opinion about the location of the preamp or do active pickups actually employ some kind of electromagnet?!

    Seems to me that all pickups are passive, but some have the preamp built in while others have the preamp on a separate PCB.
     
  9. A9X

    A9X

    Dec 27, 2003
    Sinny, Oztraya
    Essentially, yes. However the engineer as part of the design process has the opportunity to juggle a number of parameters and get different performance if there is a preamp built into the casing. This can also be done if the pickups and preamp are designed to be used together as an exclusive unit.
    Most aftermarket pickups seem to be designed to work with the maximum number of OEM and aftermarket preamps, which makes good (business) sense.
    Not that I've ever encountered, though it is an interesting idea. Field coil speakers, which use electromagnets, are some of my fave playthings.
    Yes. The detecting element is passive, ie just a coil of wire and a magnetic assembly that generates a field which is modulated by the strings and is amplified by a preamp which can be in the pickup casing, the control cavity or in the rack/combo etc.
     
  10. Thanks for that clarification, Dharmabass, just as I had suspected. I guess it's just pedantic engineers like me who really care about it though!

    So it's really just a case of the manufacturer ensuring that their pickups are only ever used in conjunction with their pre-amps.
     
  11. A9X

    A9X

    Dec 27, 2003
    Sinny, Oztraya
    No worries. I'm another pedantic (at times) engineer.
    Actually the opposite. For example, you can use Bart passive pickups with EMG onboard pres, and EMG active and passive pickups with Bart pre's, or an Aguilar, or Ken Smith, or East etc. There may be some odd mismatches, such as the EMG BTC which they've designed only to work with their own pups. I bet it's essentially the same as some of their other models, but may incorporate the EMG preferred 25k pots which makes it incompatible with typical passive pickups.
    I can only think of a few completely integrated systems; the Alembic Series 1 and 2, the Wals, the Barker, Stingrays and the Seymour Duncan Steve Bailey. The last two may work OK with the pre or pickups swapped to another type/brand, but I doubt the first three would do as well.

    From a business viewpoint it makes the most sense to have you pickups work with as many OEM and aftermarket preamps as possible, and vice versa. If you want to max out the performance of the system, and decide where all the engineering compromises are going to be, you design it all as one unit.