9v 500mA

Discussion in 'The Stomp Box' started by rockymtnguitar, Dec 29, 2017.

  1. rockymtnguitar

    rockymtnguitar Tele-Holic Silver Supporter

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    I got a new fuzz from Santa (Donner Stylish Fuzz) and am almost out of space on the power box for my pedalboard. I have one 9v space remaining and it's labeled 500mA (the rest are 9v 100mA). I don't see mA ratings on my pedal anywhere but I don't want to burn it up. Will it work okay or am I SOL?

    There are also two empty 18v ports.

    Thanks
     
  2. Thin69

    Thin69 Friend of Leo's

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    As long as the pedal uses <500mA you are fine. A power supply that has more current capacity than the pedal plugged into it is fine. A power supply with less current capacity than the pedal requirements is a fire hazard.
     
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  3. SolidSteak

    SolidSteak Friend of Leo's

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    This page says the Donner Stylish Fuzz draws 5mA. Like Thin69 said, since the power supply supplies more current than the pedal needs, you're fine (with a margin of 495 mA :D)

    Not sure you can use the 18v supply for this pedal... Donner's website only indicates 9v, so I would only use 9v.
     
  4. blackjaw

    blackjaw Tele-Meister

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    As long as it’s a 9v port and requires 9v you will be fine
     
  5. luckett

    luckett Banned

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    That's a bit of an exaggeration. A power supply working at max rated capacity will get hot, but they are designed to safely dissipate that amount of heat. The amount of power required by most pedals is very low and easily dissipated. Many modern power supplies will just shut down if they get too hot.
     
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  6. Thin69

    Thin69 Friend of Leo's

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    I didn't say "A power supply working at max rated capacity" I said "A power supply with less current capacity than the pedal requirements". Yes many modern power supplies are protected but not all.
     
  7. luckett

    luckett Banned

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    Those two statements are equivalent in the context of an analog pedal as described in the first post. A power supply that has less current capacity than the pedal requires will be working at it's max rated capacity when plugged into that pedal.
     
  8. rockymtnguitar

    rockymtnguitar Tele-Holic Silver Supporter

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    Thanks for the help folks - the way my luck runs I would have fried something. TDPRI is an amazing resource and I always appreciate the helpful replies.
     
  9. 1300 E Valencia

    1300 E Valencia Friend of Leo's

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    The milli-amp (mA) rating on a power supply tells you how much juice is available.

    The mA rating on a pedal tells you how the pedal requires.

    If the power supply says 500 mA, and the pedal says 5 mA, then the pedal will only take 5 mA from the power supply. You can't burn up a pedal by supplying more mA than it needs.

    You CAN burn up a pedal if the polarity is not matched. Most pedals run on D/C (direct current), which has a plus and minus polarity. D/C runs in one direction, from plus to minus. Running in the wrong direction (hooking up plus to plus) can damage a D/C pedal.

    A/C is alternating current, which means the electrons run in both directions. They alternate directions. Get it?
    Hooking up A/C power supplies to D/C pedals will also not be good. Most A/C plugs and jacks are a different size than D/C plugs and jacks, but they can be forced. If it don't fit, don't force it.

    There are a lot of pedals designed to run at different voltages, like 9 volts up to 12 volts. These are almost always gain types, like distortion or boost pedals. Don't assume it's OK. And, there are lots of 12 volt power supplies that are not D/C, but A/C. Also not good with a D/C pedal.
     
  10. sjwieczorkow

    sjwieczorkow Tele-Holic

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    All good advice and all true. I WILL say from anecdotal experiences that (for whatever reason) vintage synths and drum machines can be picky with mismatched amp ratings. For example, a 9V 500ma wallwart powering an Roland SH-101 will cause hum. a 9V 250ma wallwart will not. Again, this is from my personal experience.
     
  11. luckett

    luckett Banned

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    That probably has more to do with the regulation and filtering in the different power supplies than current ratings. The amount of current it can supply should have no impact on noise.
     
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  12. RiverDog

    RiverDog Tele-Afflicted

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    Okay, a possibly dumb question on basically the same topic. I have a digital pedal that requires a 9v PS. I forget what the required current is right now but that's not germane to the question. If I plug in a PS that puts out 9.3v, will that be an issue if the current rating is correct?
     
  13. luckett

    luckett Banned

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    It should be fine if it's regulated at 9.3V or unregulated and putting out 9.3V without a load. You'll probably get a small voltage drop from the reverse polarity protection circuitry and the analog components should handle 9.3V fine anyway. The voltage will further be regulated down to 3.3V for the digital components. Ask the manufacturer if you want to be certain.
     
  14. sjwieczorkow

    sjwieczorkow Tele-Holic

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    You are more than likely correct. I have found that upon switching to the original old school Roland/Boss PSA-120 (the ones with the red labels), that the noise went away. The new low profile ones are garbage. The old school wallwarts were probably of higher quality, hence the better filtering you described. I am stocking up on those old PSA-120's for this very reason. Only thing is, the rubber around where the wires attach to the transformer are starting to get a bit brittle with age.

    Oh well.

    I appreciate the intelligent response.

    -Crisp
     
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