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Advice needed

Discussion in 'Amps, Mics & Pickups [DB]' started by PhilCo35, Jan 21, 2013.

  1. PhilCo35


    Jan 21, 2013
    Sydney Australia
    My first post here so please excuse my lack of knowledge of many things. For a while I have been lurking and have read with intent (sounds like a criminal charge).

    I am a Spoken Word artist who now wishes to use an EUB of my own making to produce various sounds (not necessarily music).

    I am modifying a MiniStar Fretless Bass Guitar into a EUB, and have extended the length to 3/4 DB size. I am now assuming the Magnetic Pickup will work for Pizzicato playing, while a Piezo Pickup will be required for Arco.

    For those of you familiar with the Ministar, the Bridge (of chrome plated steel) is screw fixed to the end of the instrument. I intend to make a new Bridge (of 3mm thick Brass) of a design where the strings are raised enough for bowing. But still low enough to the neck for the Magnetic Pickup to work for Pizzicato playing.

    My question is whether a Piezo Film Pickup will work sandwiched between the brass bridge and the solid wood body of the instrument. Or will the lack of vibration render the idea useless. If so I would need advice on where to place the Piezo Strip for best effect.

    I intend to use a Balance Pot between the two pickups with a volume control for each. The EUB would be connected to a EBS Microbass II DI Box then to an Allen & Heath ZED 12FX Mixer.

    I don't require the EUB to be a fine sounding instrument such as a Musician would require, but something approximating a known sound from a known type of instrument would be desirable. The sounds at times will be going through processors and at other times the sound (whatever that might be) will be au natural.

    Thank you for bearing with me so far.
  2. GrowlerBox


    Feb 10, 2010
    Nude Zealand
    A magnetic pickup will, well, pick up the string vibrations, whatever is setting them in motion. Won't sound much like a double bass, but it doesn't appear that's what you're after. Might be worth trying before investing more effort into mounting a piezo.
  3. The bridge should not be too heavy, but the bridge feet need some area to put the pressure on the piezo (without breakng it).
    Piezo film has a very high impedance, you need an impedance buffer as close as possible (right beneath the foil is best). Better go with a piezo disc first (maybe two stacked discs for a bit higher output), but add an impedance buffer too.

    You absolutely need an impedance buffer if you want to blend both pickups.

    Personally I don't think building a fretless bass guitar into an EUB is a good idea, but for your application it might do the job.
  4. PhilCo35


    Jan 21, 2013
    Sydney Australia
    Please excuse my ignorance, what is an Impedance Buffer?
    There are no bridge feet, the metal bridge is held against the end of the wooden stem of the EUB, the Piezo will be clamped between the two.
  5. An impedance buffer is an amplifier of current, not voltage, so that a low resistance load will not drop the voltage. Some call it a preamp, but this does not neccessarily include an impedance buffer, it could be a EQ and voltage amp only. Piezos (the thinner the more) have a limited amount of electrons that can flow (immediately), so a low impedance (resistance) load (i.e. at the input of an amp) might influence the sound in a bad way (mostly in the bass frequencies).
    You might want to have a visit at Francis Deck site and read about things like that and also find schematics for a good buffer.

    Don't you think it would slip sidewards until the bridge comes down? At least put some solid metal on the piezo or the piezo sheet will break.

    I think you should have a look at some EUBs and how the bridge and pickup interact. There are even some plans how to make an EUB in the internet.
    The piezo under the bridge foot (feet) is a standard for double bass and is also found with EUBs (i.e. Stagg EDB).
    But the tricky thing is how the pressure from the bridge goes to the piezo.
  6. PhilCo35


    Jan 21, 2013
    Sydney Australia
    Thanks DoubleMIDI I'll check these things out.
  7. If you want to buy a relatively cheap complete pickup solution, get the Shadow SH-965NFX, it is a double piezo foil pickup under the bridge feet and includes an impedance buffer. If it is expensive in your area you can order it from Thomann in Germany, but check the postage!
    You can then mix the output of the NFX with the magnetic pickup using a stereo pot.
  8. PhilCo35


    Jan 21, 2013
    Sydney Australia
    It seems that the EBS Microbass II I will be using will handle the Piezo/Impedance situation.
  9. Help..i have a bbe 462 sonic maximizer..i am trying to run thru my gk rb800..or a ampeg svt 4 pro..i downloaded manual,no help..thanks
  10. Primary

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    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.

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