Power supply for multiple pedals

Started by Willthebold, August 09, 2004, 11:49:38 PM

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Willthebold

Anybody know of a good power supply that would run maybe 4 pedals or even more?  I want to build one supply with a few outputs to run several pedals.  Thanks.

Will

toneman

LM317 adj regulator, 2 resistors, 2/3 caps.
adjust to 9V.
should power 10 pedals.
google has lots of reg circuits...
afn
tone
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dolhop

Pedals don't draw much current.  You should be able to use an unregulated 9-14V DC wall-wart with daisy-chained connectors without  introducing any significant noise.   Something in the 800mA to 1000mA range should suffice.

Mark Hammer

Whether these are accurate ratings or not, wallwarts will generally come in different 100ma (milliamp) flavours.  So, you can get 100, 200, 300ma, etc adaptors.  Assume that, for a variety of reasons, you'll be able to use at least 80% of the rated current, or rather have that current available for use.

The 4 most typical pedals a player might have (eg., compressor, fuzz, wah, chorus) will generally consume about 10ma each, on average.  Some much more, and some much less.  I would not expect the quartet of effects I noted here to require much more than 50-60ma total.

Decent regulation of a wallwart (and many wallwarts provide only the barest hint of regulation) can be done in many ways, but the easiest is by means of a standard "3-pin regulator".  These come in either fixed (78x09, 78x12, 78x15, etc) or variable (LM317) flavours.  The fixed-voltage ones come in two flavours: 100ma and one amp ratings.  It is important ot know something about the total draw of your pedal board both for the purposes of knowing how much current the transformer needs to provide, and from the perspective of how taxed/stressed the regulator might be.

For example, while it may not be absolute best practice, if you had a 300ma transformer, and there was no way the pedals would ever draw more than 20ma (e.g., a couple of Tim Escobedo's FET-based wonders), regulating that transformer with a smaller 100ma 3-pin regulator is no big deal or risk.  On the other hand, if a buddy came over to your place with some recent "digital wonder" to show off that was going to suck 80ma easy, and you were *thinking* of sticking your favourite fuzz ahead of it, I'd make a point of stepping up to the 1A regulator devices.  It's more than you need for 300ma, to be sure, but a 100ma device won't cut it under your operating circumstances.

Another way to do things is to make yourself a kind of power distribution box where the DC power from the wallwart encounters a bunch of parallel 100ma regulators, one per power box output jack.  Since few single things will ever exceed 100ma, and seldom 20-30ma, a 100ma device is safe.  It,s a bit like powering a bunch of 20watt speakers with a 50w amp; sure no single speaker could be trusted with the fulloutput of a 50w amp, but if 4 share the power nobody gets pushed too hard.