G'day!

I've been using the power supply in the attached schematic to power pedals for about 3 years now (I've built six so far). It is the "standard" form of power supply for 78XX style regulators (from the spec sheet). It works with no problems powering my assorted pedals - analogue and digital, Boss and others, single and dual pedals.

Total cost was about $20. The 15VDC 1000mA "wall wart" that I use to drive it was bought at a thrift store for $1 - I think it's from a printer.

Notes:
1) The high output blue LED is optional. If you use a normal LED, change the resistor from 2k2 to 560 ohms (I used 2k2 resistor with the high output blue LED because with a 560 ohm resister, it was blinding... use a 560 ohm resistor if blinding floats your boat!). A LED should be used - the 7809 regulator needs a small load if there are no pedals plugged in, plus it tells you if the supply is actually working.

2) The bridge rectifier could be a 5 amp type if you want the whole thing to be more robust (but more expensive). I have built three of these now with the 1 Amp bridge and haven't had any problems.

3) The 7809 *must* be bolted to a heatsink (preferably aluminium, preferably at least 10 square cm in size) and heatsink compound *must* be used. The metal tab on the 7809 is at "ground" potential, so be careful with ground loops - you can use a mica washer isolating kit if you are having trouble.

4) The 1000µF and 10µF capacitors are "electrolytic" type. Higher voltages are OK, but they will be bigger physically.

5) The 0.1µF capacitors are "metal film" type. Higher voltages are OK, but they will be bigger physically. I just used some 25V ones I had in the junk box. These capacitors should be as physically close to the 7809 as possible - I soldered mine directly to the leads of the 7809.

6) To be completely safe, a fuse should be added before the bridge rectifier (1 amp slo-blow). I've never bothered because of the extra cost and haven't had problems so far.

7) To get the power to the pedals, I bought some old cheap "plug packs" at the thrift store, cut the leads off them and joined the leads all to the 9VDC output (a sort of octopus coming out of the power supply). You could also buy new connectors from the electronics store and build a chain. Be careful with polarity... center of the connector is negative/ground.


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