when a guitar pedal is powered by a 9v power supply does the mA (milli amps) output of the power supply make any difference to how to pedal is powered.
i ask this because i have some pedals which say they should be powered by a 200mA supply and some 20mA.. but the power supply i have has 300mA out put. the pedals work ok when i use it. but i was wondering if the mA output can damage the pedal in any way??

sorry .. i dont know that much about electronics

Thanks for any help!
anyone know?
*i think*

i should work alright

right now im using visual sound one spot to power all my pedals, and it has maximum current of 1700mA, which is a lot, and everything works smoothly
Peavey 5150, LTD EX400BD, tubescreamer, and a whole lotta fingers
I have a power supply which has 450mA. I think what it means is that it can only take whatever mA it has, like your power supply will be able to handle up to 30mA at once. Anything more than that will fry it.
the rule to follow is that the power supply needs to be rated higher than what it says on the pedal.
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P=VI

Therefore the actual power the pedal will get is the voltage multiplied by the current. The pedal needs the right voltage and the right current.
Quote by smb
P=VI

Therefore the actual power the pedal will get is the voltage multiplied by the current. The pedal needs the right voltage and the right current.

Hum.. i dont quite get it.. does that mean the pedal will just get the mA current it needs? so its ok to use the power supply with a higher mA output?
Quote by Neil27
Hum.. i dont quite get it.. does that mean the pedal will just get the mA current it needs? so its ok to use the power supply with a higher mA output?

The resistance of the pedal determines the actual current it will draw. The stated output current is the current a standard load would draw based on the internal resistance of the adaptor. It should be fine to use a power supply that matches the voltage but has a higher current rating.
Higher current ratings are better becuase it means you can use more than one pedal at a time e.g. have Overdrive + Wah on.
ah cool .. thanks smb!
Anything to distract myself from revision - relativity exam in an hour!
good luck!