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"Best" endpin jack for electroacoustic bass

Discussion in 'Pickups & Electronics [BG]' started by Triad, Dec 4, 2012.

  1. Triad

    Triad Commercial User

    Jul 4, 2006
    Luthier - Prometeus Guitars
    Hello! It's a new territory for me since I always used my own magnetic pickups but I've just built a semi-hollow with tone chambers everywhere... it will be equipped with a few piezo sensors (not in the bridge) but as you all know, piezo pickups don't work well in passive.
    I never liked onboard preamp and I'm considering to use an active endpin preamp, like the ones used on some acoustic guitars. It only has to boost the piezo signal to match standard preamp impedances... but before I buy every single model I see for sale out there... anybody tried a few and can give me an advice?
    For example:

    Fishman powerjack
    Shadow AC
    TM Acoustic preamp
    LR Baggs AC Acousti preamp
    Artec EPP

    I already have an Artec on the way but I plan to build a few of these instruments and even if the Powerjack is the most expensive of the lot I'm not sure it's the best. They could even be all the same product... :bag:
  2. Steve Dallman

    Steve Dallman Supporting Member

    I have several Artec's and so far, they have been great. There is one simple one, with only a Volume and Tone that might be nice, although a bass control might be very useful.

    Depending on the type of piezos, you will need an input impedance of 1meg to 10 meg. The higher you go, the more of the natural bass, and full tone can be derived from the piezos. However, you may not want full response, as the low end may put out too much body noise.

    A simple buffer, Jfet, Mosfet, or op amp can be built easily for under $10. Endpin jacks are pretty reliable, but they do fail far more and faster than standard Switchcrafts.

    The Artec will likely do the job just fine. Adding a volume control will require modifying the circuitry as the volume has to come after the preamp, so the connection to the Tip would need to be broken, and the volume wired there. (25k or 50k audio taper.)

    Some preamps shape the sound, and usually for the undersaddle pickups. I don't think the Artec does, as it is also used for their magnetic pickup and their microphone.

    If a preamp or buffer is used, and you want to mix the signals with magnetic pickups, there are other consideration. With passive magnetic pickups, you will need to add a buffer to them as well, with 10 megs for the piezo buffer and 1meg for the magnetic pickups. If the pickups are active, or you have a preamp, the piezo buffer/preamp can be mixed with the output of the magnetics low impedance output or the preamps low impedance output.

    If you will to have a blend between the piezo and magnetic pickups (if they are active) a 25k or 50k blend, like the one for EMG's will work. If the magnetic pickups are passive, you will need a buffer between the pickups and blend.

    I'd like to know more about your bass. If you don't like the Artec EPP, the other endpin preamps will not offer much more, other than volume and tone controls and maybe a little shaping, if any feature that.
  3. Steve Dallman

    Steve Dallman Supporting Member

    As I said, I have several Artec preamps. One is in my MM knockoff and in my Squier Protone 5. Those have bass, treble and sweepable mids. I put one in my Steinberger Spirit. I had replaced the pickups (that didn't pick up the outside strings well.

    I've had output level issues, so I got a new preamp, three band with a gain control. I'm having problems with that preamp though...too much high end electrostatic junk. If I take my hands off the strings, it's terrible, but even with my hands on, it can be too noisy, like through our Aviom system at church. I've not encountered this before. The pickups are humbucking and I've tried two different sets of pickups. The cavity including the batterys are shielded with copper tape. Pickup cavities are shielded.

    I've not had problems with other preamp/eq units.

    The three bands with sweepable mids have been great. Good tone control, quiet...what more do I want?