effect gizmo - terrible hum / noise again

D

darcym

Member
Hi,

late last year I started a project to re-wire my rack, and had a huge hum / noise problem,

posted this thread about it

https://www.rjmmusic.com/forum/inde...uzz-noise-when-plugged-into-front-input.3901/

Really helpful, got a replacement cable, all seemed well. Went back to re-wiring the rack. Today, I finished the skeleton of the rack re-wrire and started testing, put the effects gizmo back into the rack, huge hum / noise again, touch the front panel jack, noise changed, noticed that if the "out" is from the "from the front" jack at at the rear panel, there is almost zero noise, it only happens if I use the click stopped or / any other output, eg: from 1-4 out on the back, the "from front" works fine.

tore the rack to bits testing power supplies, cables etc etc, went and got my voodoo labs power supply and started testing the effect gizmo outside the rack, problem still there.

Made a video of it, can't believe the problems I'm having with this.

Any advice in input really welcome, had a couple of effect Gizmo's now, one lasted for ever and was amazing, until the cpu on it failed, this one worked fine as it's replacement, then has just been a pain in the backside ever since. Really keen to try to get this sorted as the enforced lock time has given me the time to actually sit down and do this in one go, rather than 30 minutes here and there.

Video Link Here

http://alesi.projecthugo.co.uk/rjm/rjm-effect-gizmo-hum.mov
 
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yes, zero impact.

if it was a ground problem, wouldn't it still impact the "from front" output too ? eg: wouldn't it still hum / buzz when using the "from front" output on the rear too ?
 
No, the system ground is connected only to the buffer and Click Stopper, all the other grounds are floating. The front panel jack to the From Front jack is literally just a piece of wire between them, it's not connected to anything else in the Gizmo.

I have to wonder if the ground lift isn't working. Can you unscrew the Gizmo from the rack and get it isolated from contact with any metal, and see if you get ground noise then?
 
check out the video, the effect gizmo is out of the rack, on a wooden desk, with an isolated power supply (totally different than the one in the rack) separated by rubber feet
 
Does it do it when you unplug everything from the Effect Gizmo? I recommend unplugging things one loop at a time and testing each time to see when the hum stops (if it does).
 
just to clarify what should be plugged in and what should the output be to test this properly.
into the front input - then from 1-4 out ? how should I test the outputs on this.
 
I recommend unplugging everything from the Gizmo, then connect guitar to Buffer In and amp to CS Out. See if you get hum. If you don't, then it's something external to the Gizmo. If you do, move through each section and test it individually. Connect guitar to Buffer In, amp to Buffer Out. See what that does. Then move guitar to In 1-4 and amp to Out 1-4 and test. Continue through each section and figure out where the source of hum is.
 
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