Multi effects box wiring (specially to avoid ground loop)

[arma61]

Hi

I'm planning, again a box with 5 effects, I've already built one (http://www.diystompboxes.com/smfforum/index.php?topic=36392.msg874190#msg874190), though it's working, I had hard time in finding the right PSU, some high pich frequency prevent from using some kind of PSU, found a solution for it, so this is gone. Anyway I think that the problem could be related to a wiring problem, so I need suggestion/advice about wiring 5 effects in a box.
I'm planning now to have "+" going from power socked to fx1 then bridge to fx2 then to fx3 and so on, then the gnd wires from each fx, from input jack and from out jack all connected together and a single wire going from this joint to the "-" on power socket, in and out jacks are metal so they will make contact with the iron enclosure, and all 3PDTs are onboard, so every OUT is going to  the next IN, and no need for gnd wire for the LEDs.

So what you think about ?
Anybody tried this kind of wiring, the one I did before had almost the same wiring but ground was bridged from one fx to the next one like the "+".

Specially is there any measurement I have to check while wiring the whole thing? I do have a DMM and an audioprobe!!         

Thanks for help m8s
Ciao

[GGBB]

There is some difference of opinion on this, but I would suggest you leave the output jack ground unconnected since it is already grounded via the chassis - just make sure it is tight.  If connected, you technically have two paths to the chassis ground from the circuit and power supply, which I think can be a problem sometimes as it is a ground loop of sorts.

There was a good thread on this a while ago: http://www.diystompboxes.com/smfforum/index.php?topic=84395.

[arma61]

Thanks Gord for reply, indeed I completely forget about that, and that's what I usually do in small enclosure! 

and thanks for the link, will have to study it a little bit.. though there's a drawing from the OP that R.G seems to approve so... I'll go for it... sure!!

Again thanks, will report when done

Ciao

[GGBB]

Note that the "RG approved" drawing uses jacks with insulated bushings so there is no direct connection between the jacks and the enclosure.  So both of the jack grounds are instead connected to the power socket ground which is in turn connected to the enclosure.  I'm assuming that is about as good as it gets for pedals and such, but since many of us use ordinary jacks we would have to make changes.  I'm not entirely sure what changes are necessary but I think it would be to simply drop the output jack ground and the power socket ground to enclosure.  The RF filtering cap is also unnecessary since the input jack ground is connected directly to the enclosure.  I personally connect the PCB ground to the input jack ground instead of the power socket ground, simply because the input jack ground lug has a lot more room on it than the power socket ground, but I don't know if that's any better or worse than directly to the power socket ground, especially in the case of multiple PCBs.

[arma61]

yes, I have both metal and plastic jack so will try both solutions and choose the best/noiseless one.

Thanks
Ciao