Electricity question
Aug. 29th, 2009 12:24 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
thedarkprojectI have 3 guitar pedals, that take 9V DC power. The current draw on each one is 17mA, 20mA, and 55mA respectively. Mains power here is, what, 220-240V, 13amps? The AC/DC transformer is going to use some power itself, but I would have thought that getting 90mA from one power source would be easy.
So why does the guitar shop recommend power supplies like this one which cost £100? Surely I should be able to just take a normal 9V DC supply and run it in parallel to each pedal?
So why does the guitar shop recommend power supplies like this one which cost £100? Surely I should be able to just take a normal 9V DC supply and run it in parallel to each pedal?
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no subject
Date: 2009-09-08 01:50 am (UTC)1) When converting from AC to DC, the DC output is not constant but wobbles a bit to the cycle of the AC, potentially causing a loss of quality. Higher quality AC->DC converters will have less of that.
2) They want to make money.
Considering that they are guitar pedals, I think #2 is the much more likely option.