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Pedal Power Connector Standardization

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9/2/1999 3:03 PM

Dean Hazelwanter

Pedal Power Connector Standardization

I'm making a bipolar 9v power supply for a pedalboard for my Son. All of his Boss pedals, the Jim Dunlop Crybaby he's borrowed, as well as a few other toys use the coaxial (barrel) type with positive ground. A lot of the toys I've built are negative ground, including the Big Muff. I'm about to start adding external power connectors to some of these home-grown effects, and wondered if there is any kind of standardization of the connectorization for positive versus negative grounded systems, or even barrel type versus other types such as 1/8" phone jacks.

Thanks in advance for any input.

9/2/1999 5:23 PM

Unfortunately from what I have seen there isn't a standard. However, most OEM's choose between 3 different sizes. Boss uses 2.5mm ID type (I think) and I have seen others use the 2.1mm ID sizes. I have a reissue Flanger from DOD that uses a mono 1/4" jack for their power plug.

My suggestion would be to design in your pedal board a power supply bus that uses all of the same connectors as outputs from the supply. Then make short jumper cables that mate to your bus and the other end of the cable would be 2.1mm ID DC power jacks and another with a 2.5mm ID or whatever your pedals require. This way you can put any pedal in your board and create its own DC power jack.

CJ

9/2/1999 10:35 PM

Dean Hazelwanter

Thanks for the comments, CJ. I did the PCB layout for the supply with a 4 pin screw-terminal block, +9, gnd, gnd, -9. This will be mounted in a metal enclusure with a removable top, so depending on what's needed *I* (not my 15 year old!!) can connect whatever kind of cables to either the positive ground or negative ground bus. I may use the barrel type for all positive ground effects, and 1/8" phone for the negative ground effects, just so he can't mix them up and let the smoke out of one of the boxes.

9/3/1999 3:51 PM

Based on the concept CJ described, my power supply source feeds a junction box unit which has an array of RCA phono jacks (insulated from the box, if you use metal box) connected to the regulated power source. Rather than messing with screw terminal connections for my individual jumpers to each effect, my jumpers have an RCA plug on one end, and the required FX mating power jack connector wired for correct polarity on the other end. RCA jacks are cheap, and they are foolproof in that they are open circuited when the plug is pulled out, either deliberately or inadvertantly. Jumpers can be tailored in length as necessary for a neat pedalboard wiring layout, or made extra long to accomodate any rearrangement, your choice.

Just a suggestion to make it kind of foolproof, since a 15 year old (the guys who always seem to break input jacks) will be the primary user.

9/3/1999 12:11 AM

Dean, I will get down in the amen corner with you all day on this one. The world would be a better place if there was a standard, oh well. Every single one of the pedals on my gig-rig has a different type of DC-in jack, ARRGH!

When I got a switching power supply and realized its stock cables didn't fit my pedals, I thought and thought about how to fix it (with the help of Ampage, of course), and finally took the 'easy' way out. I got some jacks that fit the power supply and some 9V battery clips and made patch cords. I go straight from the power supply into the pedal's battery input. This required no modification to the pedals, and all the cords are interchangeable (no worries about polarity or jack-type).

NOTE: If you do this, double-check your polarity before plugging in. As you might have guessed, since the two battery clips are connected +/- and -/+, you have to reverse polarity at some point to compensate (dumb but easy mistake to make).

Best of luck.

9/3/1999 6:01 PM
Gus	1/8" note When using the 1/8" power plugs it is a good idea to plug them in before you plug in/turn on the effect power supplys. When pluging in the tip and sleeve can short against the sleeve connection in the jack.

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