power source for double pedal

[sevenkill24]

hey, if I wanna build a double pedal, i:e, 2 effects in one case, individual controls, do I  need 2 9v power sources? Should I build it as 2 separate circuits, or one complete circuit? Any help would be greatly appreciated.

[Kearns892]

You could use a single power supply unit, it will just draw more power. You could use a single circuit board, but there's no real need to. Having two boards will make offboard wiring and debugging much easier as if you get one right and one wrong, you don't have to uproot the whole thing. I have switching diagram for a "double pedal" already drawn up if you would like it, but I won't clutter the thread with it if you don't need that.

[deathfaces]

i'd be interested in seeing that switching document.

[Kearns892]

It's nothing special, just two 3PDTs wired for True by-pass, only the output of the first is the input of the second. Still though here you go.



C1I and C2I are the inputs for Circuit 1 and 2 respectively, and C1O and C2O are their outputs. Everything else should be self explanatory.

[boogietube]

Here's a diagram...

http://www.generalguitargadgets.com/pdf/two_in_one_wiring.pdf

[deathfaces]

so basically, to power two effects in one box, if they are drawing over 9 volts together, you could just bump up the voltage to compensate. i know voltage is the same across all components, so as long as you dont go higher than the part ratings you should be fine. in other words, up the voltage, but dont send 16volts through a chip rated for 12volts.

[boogietube]

You may be confusing power with voltage. 9 v in the diagram would be sufficient to power most 2 pedals together. It's current draw that translates to power consumption. If you had a 9v 100ma adapter and tried to run 2 hungry effects  together it might heat up or damage the adapter. 9V 200ma is what most adapters are (Boss) , so you should be fine in that case with 2 pedals. Batteries are a different story. You'll drain 1 battery with 2 circuits rather quickly.
Of course, you may be talking about fet emulators and many people have had great luck improving "headroom" with boosters and distortion devices using a higher voltage supply.
Cheers.
Sean

[deathfaces]

that makes more sense.  i did have power and voltage confused, so its wiser to feed those hungry effects a 9v 500ma or 9v 1a adapter.

is it safe to use an adapter with a higher amperage, and unsafe to use one with a lower amperage? for example, i've got a 9v pedal that draws 160ma, but i've only got a 9v 500ma adapter.

as far as voltage goes, regardless of headroom, if i've got a 9 volt 200ma circuit, but only have a 10 volt 200ma adapter, its not likely i'll do any damage to the pedal unless the components are rated less than 10 volts, correct?

[boogietube]

Yes. Correct on all counts using the numbers you supplied.
.