So I fabbed up what I thought would be a nifty little patch box to get the analog keys talking to my pedalboard, but the hiss is unbearable as soon as I link it up to anything on the board. It’s just point to point wired 1/8" to 1/4" mono jacks. There’s no power to it so I didn’t think grounding would be an issue and the hammond box should provide adequate shielding. Touching the box or jacks does not modify the noise the same way you might find with RF interference. Any thoughts from more experienced tinkerers?
what are you doing with it ?
you have 4 1/8 jacks and 4 1/4 jacks
is this for sound or cv
CV outs are TRS and need splitter cables to distribute the 4 CV signals
try feeding something battery powered through your box to verify it’s all fine (which it should be) … probably some ground loop thing happening, so testing a battery powered device (if applicable) may help
edit: just saw title says CV doh !
how have you wired up the jacks ? have you TRS or are you breaking out TRS to TS 1/4 and then converting size ?
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Well I was originally going to try keytracking the Protostar filter but discovered that feature doesn’t exist on the CV track. 
But anyway, each 1/8" jack is wired to a 1/4" jack. They are mono jacks, so 2 wires for each connection, tip and sleeve.
The top 1/4" jacks in the photo take CV from the AK (via insert cable) and convert to the top 1/8"jacks.
(The connections seem fine, btw, no apparent issues as CV control from the AK works fine)
The lower 4 jacks will patch in a couple of expression inputs. I haven’t dabbled with that part yet. Just working with the filter so far. Still need to hear back from one manufacturer on whether CV is ok for their exp input.
It’s all just a $25 experiment and a bit of tinkering fun. But it could turn out some interesting results!
If your design is jack --> cable --> jack and no kind of electronics inbetween … it should work properly for audio frequencies and below.
I guess, you could improve with some grounding and/or shielding inside the box. If your box is electronically passive, external noise should be the only source for “noise”.
AFAIK each standard jack has plus/minus/shield connections. I suggest using cables having two wires and shield. If your box is made from metal, you should get a ground contact too. Gives you a kind of Faraday cage 
and protects against external frequencies of other gear.
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Thanks! I’ll keep troubleshooting and report back.