Members Dogoth Posted March 29, 2014 Members Share Posted March 29, 2014 I have a friend who manages a small theatre. He occasionally has a problem with guitars & basses with single coil pickups that pick up his lighting dimmer noise. Interesting enough he says it is present at any level of lighting other than 0% (usually 100% will make no noise as well since the triac stops working and there is no HF harmonic). It is definitively from his lighting dimmers. They are Strand dimmers so I figured that they should have adequate chokes inside (some low end companies will cheap out on the copper :-). I told him that really, it's best to use as good of a guitar cable as possible and make sure the instrument is shielded inside (my standard answer to RFI problems). Of course they are not his instruments and he has no control over what an artist brings. I guess this is more of a problem in his theatre than where I work (we RARELY have any dimmer noise problems but out dimmer rack is on the other side of a lot of re-bared concrete & steel beams). I was just wondering, is it possible to do the reverse, and shield the dimmer racks? would it require a solid plate (grounded to any good non current carrying ground) or would metal screen work (like a Faraday cage)? My understanding of RF is limited but I thought I'd ask here as I know there's a couple of good engineers that might know it it is worth trying. Link to comment Share on other sites More sharing options...
Members agedhorse Posted March 29, 2014 Members Share Posted March 29, 2014 Does it occur on a single dimmer or as part of a scene? Does the noise change with load (ie. heavily loaded scent versus lightly loaded)? Two possible paths of noise entry, radiated and conducted. Fixes are entirely different between the two. Link to comment Share on other sites More sharing options...
Members Dogoth Posted March 29, 2014 Author Members Share Posted March 29, 2014 I've not witnessed this myself but I've asked and will let you know ASAP. This theatre is out of town and gets used (for real shows) every month or so. He said he's going to take a noisy guitar and small amp with him next time and experiment. Put this one on hold until further troubleshooting can be done. Great little Theatre though. Thanks for the direction. Link to comment Share on other sites More sharing options...
Members Gordon Sound Posted April 1, 2014 Members Share Posted April 1, 2014 Is he running the dimmer control via the snake? Link to comment Share on other sites More sharing options...
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