9 volt power supply question

Discussion in 'Effects, Pedals, Strings & Things' started by teddys, Oct 13, 2008.

  1. teddys

    teddys Member

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    I have a bunch of the 9 volt supplies from various phones, and consumer electric devices.
    They are all from 150 - 350 ma.
    Are there any issues using these in place or in addition to the BOSS 9v "universal" supply?

    thanks in advance
     
  2. allmonochrome

    allmonochrome Member

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    just make sure that they have the same polarity as the pedals that you are going to power them with. i've also found that "random" power supplies such as those can be noisy.
     
  3. GuitarToma

    GuitarToma Silver Supporting Member

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    I agree - polarity is everything - but some transformers create a larger and noisier field. It's trial and error really. But to answer your question - as long as the voltage and polarity is correct they won't cause damage to your pedal.

    Oh - I've also heard to never use an adapter that was made for charging a device, such as a cordless phone charger. I don't know the specific reasons why not, but have heard to not do it.

    Good luck!
     
  4. Tonefish

    Tonefish Member

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    matching up AC-v-DC(very important and often overlooked), voltage, polarity, plug-size and minimum current available has worked for me everytime.
     
  5. amp_surgeon

    amp_surgeon Member

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    The PSA-120T is actually a good quality supply. It has a solid transformer, full-wave bridge rectifier, three filter capacitors, and a 9V regulator IC mounted on a heatsink. It's not a bad deal for $25.

    Many low budget supplies use only half-wave or full-wave rectifiers, rather than full-wave bridge, and they don't provide enough filtering capacitance, so there's a lot of ripple in the DC. Ripple equates to 60 cycle hum. Many also don't have voltage regulators, or use only a zener diode for voltage regulation. This means the voltage can surge or sag when the load changes. All of these things can affect your sound, especially with analog pedals.

    The short of it is that having the right specs on the box doesn't necessarily mean it's going to perform well. If you get noise with the adapter that you don't get with batteries, then the adapter isn't well suited for that pedal.

    BTW, I don't like the new PSA-120S supplies from Boss. They do deliver twice the current in a smaller package, but they're switching supplies. The high frequency oscillator causes a whine with a lot of the analog pedals I've tried them with.
     
  6. Tonefish

    Tonefish Member

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    ^that's good to know...thanks!!
     

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