Lotos
Active Member
Alright, so here's the real "Uhhh....." moment of my week, perhaps the inquiring minds around here might be able to answer my riddles three... (Or one, really...)
We just opened (second preview tonight) our current show, and tech is pretty much nailed down at this point. In amongst the insane amount of lx that my crew(s) have managed to pull off over the past 4 days, are 240 MR-16 EXT Lamps, wired in series circuits of 10.
These circuits, for the most part, are working wonderfully, and are powered via several NSI DDS 5600 shoebox dimmers.
One of the channels (and only one) are causing an interesting ground hum through the main PA... This has happily stumped myself, our TD, and our Head of Audio...
Let me give you some details:
The sound console is located at the rear of our room, on clean conditioned power.
The lighting console is located nearby, on seperate power.
The shoebox dimmer in question is located under the stage, powered from a breaker panel backstage.
The lines from the circuit of 10 MR-16's runs directly to the dimmer, avoiding all audio cable on the way.
So naturally, when the hum showed up, we were confused... Especially when the audio operator stated that he had almost everything (including everything on deck) muted.
The problem went away when the main outputs of the sound console (Innovason SY80) were muted, so the problem wasn't beyond the console.
Finally the errant input was found, our SFX Computer's line in. (Also running on conditioned power)
The SFX computer is powered via a circuit in the balcony (currently closed, thus we have prime Stage Management seating right now).
When traced, this routes back to a breaker panel in the theatre's electrical room, running off a seperate transformer than the backstage breaker panel powering the shoebox dimmer.
The feeds would only cross at the pre-transformer point...
So I'm stumped... What on earth is causing this wonderful ground hum we're hearing?!?!?!
I mean, obviously it's that circuit of lights, and obviously the SFX computer's lines are producing it...
But how?!
We just opened (second preview tonight) our current show, and tech is pretty much nailed down at this point. In amongst the insane amount of lx that my crew(s) have managed to pull off over the past 4 days, are 240 MR-16 EXT Lamps, wired in series circuits of 10.
These circuits, for the most part, are working wonderfully, and are powered via several NSI DDS 5600 shoebox dimmers.
One of the channels (and only one) are causing an interesting ground hum through the main PA... This has happily stumped myself, our TD, and our Head of Audio...
Let me give you some details:
The sound console is located at the rear of our room, on clean conditioned power.
The lighting console is located nearby, on seperate power.
The shoebox dimmer in question is located under the stage, powered from a breaker panel backstage.
The lines from the circuit of 10 MR-16's runs directly to the dimmer, avoiding all audio cable on the way.
So naturally, when the hum showed up, we were confused... Especially when the audio operator stated that he had almost everything (including everything on deck) muted.
The problem went away when the main outputs of the sound console (Innovason SY80) were muted, so the problem wasn't beyond the console.
Finally the errant input was found, our SFX Computer's line in. (Also running on conditioned power)
The SFX computer is powered via a circuit in the balcony (currently closed, thus we have prime Stage Management seating right now).
When traced, this routes back to a breaker panel in the theatre's electrical room, running off a seperate transformer than the backstage breaker panel powering the shoebox dimmer.
The feeds would only cross at the pre-transformer point...
So I'm stumped... What on earth is causing this wonderful ground hum we're hearing?!?!?!
I mean, obviously it's that circuit of lights, and obviously the SFX computer's lines are producing it...
But how?!