Building Pedalboard Power Supply, Questions about outputs

[kevilay]

Hey guys ive designed a pedalboard power supply. Its outputs very clean level power at many different voltage ranges. 9v, 12v, 15v, 18. I could still adapt it to run on something else if necessary. My question to you guys is... How many outputs for each should I have? Of course Im limited by current, but according to my calculations I should be able to run close to 20 average size pedals. What I was thinking was, 2x 18v, 2x 15v, 2x 12v, and 8x 9v outputs. Any thoughts or opinions on this? Or Suggestions to help improve my build. Also one more thing. From what ive seen all pedal power input jacks seem to be the same polarity and the same size? Is this true for all pedals? or do I just happen to have all the same size jacks on my pedals.

Any input is greatly appreciated.

Thanks,
Kevin

Edit: Just to clarify it runs all these outputs at the same time. Meaning you could run 2x 18v pedals, and 6x 9v pedals at the same time.

[Mark Hammer]

2.1mm is the standard for adaptor input jacks, although pedals will vary in the depth of the jack, and how long the shank of the plug needs to be to actuate the battery-to-external switching at the jack.  Some pedal jacks also don't provide enogh space around the jack for anything less than the longer-shank ones to be inserted sufficiently deeply.

If you've built the supply partly in anticipation of your own DIY pedals, AND those pedals have unique power requirements, you might want to consider using some sort of unique jacks (e.g., 2.5mm) on either the pedal, the power supply, or both, as a way of making sure they get the right power.  The same might apply to any reverse polarity pedals like GE-based, where you want to make sure you're providing the right voltage AND polarity.  Another way to do the same thing is to use distinctively colored heat=shrink tubing on specific kinds of power cords/voltages.

[kevilay]

well that depth issue could be quite annoying. what happens if you take a longer depth one and plug it into a shorter depth pedal? Does it just stick out a little bit?

I wasn't aware some pedals use different polarity supplies. I guess i could have two different kinds of cables, one for each polarity.

[Ben N]

well that depth issue could be quite annoying. what happens if you take a longer depth one and plug it into a shorter depth pedal? Does it just stick out a little bit?

Yup. Usually no harm.

[Mark Hammer]

No harm, yes, although in some contexts the extent to which it might stick out could make close nestling of pedals on a more compact pedalboard somewhat awkward.  In, which case, it might be useful to have a couple of different power patch cables, some with longer plugs, and some with shorter ones; no big whoop.

[Perrow]

well that depth issue could be quite annoying. what happens if you take a longer depth one and plug it into a shorter depth pedal? Does it just stick out a little bit?

I wasn't aware some pedals use different polarity supplies. I guess i could have two different kinds of cables, one for each polarity.

Note that 9V negative supply isn't always the same as a 9V positive supply with a crossed cable. You would also probably run into short circuit problems with a crossed cable into, for example, a Ge PNP Fuzz Face if used together with other NPN circuits.