Possibly cool idea for stompbox layout. Want some feedback....

[studiostud]

Hey.  I have an idea that I want to try in a stompbox I'm building and I wanted to get some feedback from more experienced folks on whether or not this should work in theory or if something about it would screw everything up.  One of my main frustrations with building stompboxes is that a lot of times it's hard to get to all the offboard stuff to troubleshoot because there are tons of wires and a PCB board all in the way.  And then, if I'm lucky, I won't break a wire while I'm jiggling everything around to get to something. 

So my idea is to use another smaller piece of pre-etched PCB as an "offboard wiring" board.  (I know, kind of an oxymoron)  Then I could wire all the offboard components to that PCB and secure it to the bottom (I guess technically the top) of the enclosure, secure all those wires out of the way, and then make any necessary connections to the onboard PCB.  Now that's just part of the idea.  this still leaves me with several wires going from one PCB to the other.  This is where the idea comes in that I want feedback on.  I was thinking of a type of "plug and play" connector if you will and what came across my mind is a 40-pin EDIE cable like what is used on hard drives in computers.  I wouldn't use the actual ribbon cable, but I know you can get the connectors at many computer electronics retailers.  So in theory, I would solder a female EIDE connector to the offboard wiring PCB and make the necessary contacts and/or jumpers.  Then get a male/male connector and solder the neccesary wires that connect to the onboard PCB into the appropriate places.  Now all I have to do is disconnect the EIDE connector and I can take out the onboard PCB and all the offboard wiring is easy to get to.

My main concern, since I don't know much about EIDE cables in the way of technical info, is whether or not the EIDE can handle this type and amount of voltage/current?  Also, I know the pins on the connectors are isolated, but if I used it for this purpose, would I get any bleed that would adversely affect the function or sound?  Thanks in advance for any feedback.

[Pushtone]

EDIE headers will work as will virtually all other header types. Voltages in stompboxes are very low in general.

However, There are much better headers available, smaller with set screws to lock your wire in place.
Check the Mouser site for headers.

Using headers should be enough that you will not need a second PCB. Just put the header on the main PCB.
Check out the layout for the 6-band EQ at GGG. One edge is a header I/O.
Just pop out the PCB to get to the pots.



I tend to lean toward the cheap. From a tip I got here I weave the leads through the PCB for strain relief.
I can handle it roughly without wires breaking.

[Paul Marossy]

From a tip I got here I weave the leads through the PCB for strain relief.
I can handle it roughly without wires breaking.

Yep, that's pretty bulletproof. 

[Mark Hammer]

In principle, the idea of easy-to-disassemble pedals is a terrific one.  I question your use of an EIDE-type edge connector.  It is likely much better to use several separate smaller connectors.  Certainly one reason is that gathering all the on-board connections to one location/connector means greater trace length and bigger boards as a consequence.  The corollary to that is that all your pots and switches will similarly have to return to one common point, which increases the risk of crosstalk, the overall bulk of the wires, the risk of tearing, and the required enclosure size to accommodate all that bunched up wire.

So what to use instead?  Right at this very moment, there are tons of dead PCs lying around with all those twisted pairs and trios of wires that go from panel switches and beeper speakers to the header on the mother board where you connect your reset, HDD LED, power LED, speaker, etc.  You can buy male header strips with 40 or however many pins that can be broken off to the size and number of contacts that you want.  A couple of male in-line headers on your PCB will take very little room and you can run short-length twisted pairs/trios to them from switches and pots that you have scavenged from old PCs.  The wire come preinstalled in the female connector and all you have to do is clip it and solder it to the panel-mount components.  You can run your control connections along one edge, and your power, switch, and jack connections along the opposite edge.  can't get much cleaner than that.

[Processaurus]

Peak inside any boss pedal with 4 little knobs.  They do a mini PCB that all the little pots and rotary switches mount on, and use a ribbon cable to connect everything to the main board.  They don't bother with a header, everything's just soldered to the board.  They use a weird yellow glue on the wire ends to stop them from breaking at the boards.  I do the same with hot glue.  Its messier and easier than the weave the wires through the board technique.  Its also messy to change stuff around (but doable), so that would be better for stuff that isn't experimental.

Pushtone, the idea of having a header or headers only on the board side, and just soldering the wires out onto the pots and switches sounds like a nice way to do thing, as long as you could get pre fabbed ribbon cables with a connector on one end already, its such a pain putting on individual connectors to individual wires, like the molex type.

[Pushtone]

I was thinking of these PCB type headers, if thats what they are called.



Wire would be soldered to the pots switches and disconnect at the board via these terminals.
They have a set screw that clamps the lead.

I think they are the way to go but they are expensive, which is why I don't use them.
If I need to work on a circuit I take everything out of the box in one clump of components and wires.