Ground Loop Elimination with custom dual 13 pin cable from guitar

Started by StudioBill, November 28, 2012, 12:02:37 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

StudioBill

Hi everyone, I'm a long time lurker on the Forum, and am in the process of working on a pretty complex guitar and AXON, GR-55, GR-1 guitar/synth rig. I'm using a second 13 pin cable to route signals from some Infusion Systems "gestural" sensors for MIDI-based Fx and synth patch CC modulation. (3 touch and pressure sensitive pads, an "orientation, or "tilt" sensor, and a proximity sensor) I was going for the most flexibility and unusual controller sources..(!) Anyway, the two 13-pin cables together (1 to the Roland 13 pin parallel splitter, and on to GR55, GR1, AXON 100 MkII, and the other to my InfusionSystems Digitizer are ( as I should have expected, I suppose), wreaking Ground Loop havoc...and I'm not sure how exactly I can eliminate it. The Digitizer line involves +5 and -5 volts plus a third conductor on the "Tilt" and Proximity sensors. I believe they have a signal +, signal - and a separate power conductor as they are active sensors; the pads have only two conductors. I laid these out using 12 of the 13 pins, and did nothing to tie the shield at either end---WHICH, I belatedly realized just now, could be my real problem..(!) However, I'd still very much YNXPRRappreciate any input or advice on this aspect of my rig as it relates to ground loop problems, since I've got hum I could sing along with cheerfully---due to the impossibility of hearing me over it..;=)    StudioBill

PS--Just learned something else...you can't type "Geeetahh" into the human verification field...

Brent Flash


StudioBill

Hi Brent, and thanks for the welcome...Over the past couple of years I have learned so much from the folks on this Forum, and, collectively, you have all saved me uncounted hours with Tips, Tricks, schematics, etc, so I'd like to offer all a heartfelt "blanket" thanks...I've been at work on this rig in one form or another for four years, and have pulled off some things onstage that I wouldn't have dreamed of in years past..(think:Kontakt Sax & Brass horn section rhythm part while alternating guitar and sax {NI's SaxLab} solo lines, all more or less impromptu at a sit in gig with a friend's roadhouse blues band in a Denver club) THAT's the kind of night that can keep you interested through interminable hours of gro9und loop sleuthing, all night soldering sessions ("I love the smell of Rosin in the morning...it smells like victory.." [apologies to 'Apocalypse Now'] Thanks again for the welcome, you'lll probably hear more from me in the near future, getting to the final patch programming phase (Little Giant 2) of the development...actually I've got a Receptor2 Pro in the rig as well, and, all I can say, is that the samplers and sounds have gotten so good, that I find the limiting factor has become....ME! At first I sounded so much liike a guitar player doing horn runs and stabs, that I had to take a course in horn arranging...much better now, and as a bonus, my sax soloing sounds MUCH more like how I wanted it to sound, and much less like "Smoke on the Water as Interpreted by a Small Jazz Ensemble"...as intriguing as that might prove to be...<smile> Interesting side developement---my guitar soloing has gone off in new and interesting directions after studying sax, violin and B3 soloing techniques and kinda absorbing a bit through listening osmosis, so to speak...

Elantric

I missed this post before
On the GK-13 cable , no pins are used for Ground - the only connection for the crucial Ground connection is the large chrome circular shell on the DIN13 plug.
Since you have two 13pin cables, you have multiple paths for ground.
Taming ground loops can be a battle which requires careful diagnosis.

Search on "audio ground loops" for further reading.

Implementation of a "star ground" reference typically solves noise issues. ( or disconnecting the electrical connection from the Ground Shell on only  ONE of your DIN cables might help too)

But new electronic gear (laptops, VG-99, GR-55, etc) all use "green energy efficient" Switching Power supplies, and when those supplies get in the middle of a ground loop, the resulting noise is high frequency "Hash/Hiss" instead of the typical 50/60 100/120 Hz Hum.