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Battery box for Schertler Preamp?

Discussion in 'Amps, Mics & Pickups [DB]' started by robobass, May 6, 2010.

  1. robobass


    Aug 1, 2005
    Cologne, Germany
    Private Inventor - Bass Capos
    I have the Pre A II which takes 12v. I have an after market adapter which puts tons of hf noise into the signal. I don't want to drop the bucks on the OEM unit, and hate having another thing to plug into the wall anyway, so I'm thinking battery. The unit draws about 50mA, so I could make up a little box with 8 AAA's or 10 AAA NiMh's, which is what I guess I'll do, but I thought someone here might know of an option I haven't thought of. Fdeck, you out there?
  2. JtheJazzMan


    Apr 10, 2006
    Are you certain its the power supply thats the problem? I recently bought a Pre-A III which had an extreme amount of white noise. I had it swapped for another unit and my heart sank when I plugged it in only to find that it was less noisy, but still by far the noisiest thing in my signal chain.

    To answer your question I just linked 2 x 6v lantern batteries together to give a 12v power supply, then bought the correct DC plug which was 5.5mm outer ~2mm inner.

    Made no difference to the white noise. The mains power supply was introducing some extra hum, but it was only detectable with my recording software. To the ear it was drowned out by the WN.

    Hell even my home-made condenser mic preamp and piezo preamp based on fdecks design are silent.
  3. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Is it possible that you are using a switchmode DC adapter? Is it really tiny and lightweight? Those may put out a lot more HF noise than the good old transformer-based adapter.

    It might be worth trying a 9-V battery. Damage is unlikely, and it would be convenient if it works. Just don't push the highest signal levels.

    But if as JTJM says, the preamp is introducing the white noise, then it's going to be a tougher nut to crack.
  4. robobass


    Aug 1, 2005
    Cologne, Germany
    Private Inventor - Bass Capos
    My adapter is transformer based and was claimed to have good filtering, but who knows. I did try a battery when I first got the Pre A II and remember it helped quite a bit, but yes, it didn't get rid of the WN entirely. I just ordered a battery box and will report back when everything is rigged up.

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