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Can we talk about this bad habit with ground loops on the bench?

I used to think any old wiring setup was fine for testing. Then last month I spent 3 hours chasing a glitch in a Garmin G5 install that turned out to be a ground loop from running signal wires next to power cables on the test bench. A senior tech showed me how even 6 inches of parallel runs can cause noise issues. Now I always cross power and signal at 90 degrees and it's saved me at least two more headaches since. Has anyone else run into this and found a fix that works better?
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3 Comments
lane.cameron
Cross your wires at 90 degrees and keep signal wires short. Same principle applies to my home stereo setup where speaker cables twisted next to power cords made a hum, and it went away once I separated them.
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kelly385
kelly38515d ago
Oh man that's a good point about the 90 degree thing! What gets me is how many folks forget that the metal used in the connectors matters too. I had a setup where I was using gold plated RCA cables but then I cheapied out on the ground wire, ended up with a nasty ground loop hum that drove me crazy for a week. Swapping to a braided copper ground strap fixed it completely, even with the same 90 degree wire routing.
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seanlee
seanlee15d ago
Keep power and signal separated even in your house wiring @kelly385, same reason your fridge hums near your TV.
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