Elmo GS1200 static crack when touching GND rings of input/output connectors

[Patrick Steemers]

Hi all,

on my Elmo GS1200 I have no crackle anymore when turning knobs or throwing switches. Only when powering off with the power switch there usually is one loud crack. By the way NOT when I unplug the mains with power on.

However, when I touch the input connector of for example the headphones at the ring with a metal object there is a static tick or crack every time. Also for aux in, mic or PA into aux outputs.

seems like some sort of grounding problem.
anyone any idea what this is and if it can or should be solved?

many thanks in advance!

[Steve Klare]

Hi Patrick,

This isn't a grounding problem, it is actually ground doing its job. Just being a human being scuffing around on the carpets, you are building up a surprising amount of voltage (-some might say "shocking"!)

Then you touch these connectors, which are all grounded, and this brief, huge burst of current runs through the chassis and sprays magnetic fields around things like the sound heads and such on the way out to the ground pin on your power cord.

I'll give you odds if you touch some other ground as you are touching these, you'll never hear these ticks.


Summer is coming: the humid air helps a lot to bleed these charges gradually and harmlessly. My wife and I traveled to Russia years ago. It was February and -20C every day. Any hint of moisture for the air was locked outside as ice and snow. Crossing a room and grabbing a doorknob was downright painful: there was literally a lightning bolt! We held hands and took turns grabbing the knob (and taking the hit) so we could go from room to room at the hotel.

-and that's how static electricity (and marriage) work!

[Brian Fretwell]

I once halted a mainframe computer (with crowbar power supplies) when touching it with a trolley transporting 1/2 in magnetic tapes that had plastic wheels. It seems that wiping the plastic tape cases had built up a very large charge. The computer could also be caused to power down by nearby lightning strikes causing "earth spikes".