I'm thinking about building a power distribution box for my upcoming pedalboard project, using JD Sleep's Ultra Clean Power Supply.  I'm going to have three +9V output jacks on each side of the Hammond B box wired in parallel with each other.  I'm going to use a 120VAC to 24VAC wallwart to power the distribution box.  I'm looking for one that's around 800mA so that I'll be able to easily power the pedals.

I was wondering if I could wire the cables on the power box side up so that the center pin is positive and the outer part of the jack tip is negative, so I can use metal power jacks, and ground the box at the same time since the metal jacks will also ground the enclosure.  

The effects pedal side of the power cables would be wired up in the more standard negative center in, positive outside.  The DC power jacks that I use in my effects are the plastic body ones that isolate the positive outer sleeve from the negatively grounded case.  Would this setup cause any problems?

Phillip

Thats a new idea. I'm not too experianced, but i might be able to help. Let me get this straight. You have 3 center positive power supplys and want a box that converts them into 3 center negative lines to feed to your effects, right?if that is so, then yes you can ground the box using metal jacks (on the power input side) that have their chassis as negative, but an easier way would be to get all plastic jacks, and wire it so that from the input, the negative lug goes to this power box's case, and the positive goes to the outer lug on the output side. then the inner lug (center on the output side goes to the power box's case also). wow thats making me dizzy :?

LM 250+

P.S. I like the layouts on your website, though the one for the LPD (EH) can be smaller.

Hmm if I used plastic jacks on the power distribution box, I would have to find another way to ground the metal enclosure, but it would certainly work that way.

Phillip

you could use the daisy chain the negatives off the power input side, and put one wire to daisy chain the out's and another to the case to ground it. This way your system is grounded.

As in this

input                           input                            input                 case
+    -                          +    -                            +    -                   |
|     |______________  | __|_______________  | __|___________|
|                                 |                                  |                         |
|                                 |                                  |                         |
|                                 |                                  |                         |_
|___________________|___________________|________________to out

then reverse the leads to the output jacks to make them center negative.

LM 250+

Metal input jack and neg outside input plug is completely compatible with an insulated (ie plastic) positive outside, negative pin output plug(s).  No worries.  Assuming ground on your boxes is going to be -ve, you're cool.  Otherwise (ie a +9V earth) :shock: sparks.

Your DC output jacks will work fine (neg. outside metal jacks to metal case).  Obviously your DC cables will be wired as 'polarity reverse' cables.  The only thing to do is make sure your 24VAC input jack is isolated from the metal enclosure.  You don't want your AC connected to DC ground.  Use a plastic jack on the input.

IMO, that's asking for ground loop problems from HELL!

If you must ground the case, ground it at one point and only one point, and connect ALL other grounds to this same point.

It's far easier (and less suceptible to a whoopsie) if you just have a wire, soldered to the circuit board ground and connected somehow to the internals of the case.

You may regret doing tricky stuff with your polarity on DC cables.

QuoteI would have to find another way to ground the metal enclosure

gee, you make it sound like such a chore!  Short bit of wire, solder to circuit board ground, crimp a round lug or solder other end to slightly out-size washer, bolt it to bare metal!