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Dimmer Pack on a Dimmer

Discussion in 'Lighting and Electrics' started by Lynnchesque, May 9, 2019.

  1. Lynnchesque

    Lynnchesque Member

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    Ah, the age old "Can I put it on a dimmer?" question.
    I'm running into power limitations in an old space, so as the title says, is it a bad idea to plug a dimmer pack into a parked dimmer circuit?
    And before you ask, "If you have a dimmer, why do you need a dimmer pack?" For reasons. Dusty 1970s reasons.
     
  2. Amiers

    Amiers Renting to Corporate One Fixture at a Time.

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    No, but you can TIL you cant. if you need the extra circuits and no other options do so at your own risk.
     
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  3. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    What kind of dimmers? Use to put autotransformers on resistance boards just fine.

    If scr, I asked about an SE750 on a Sensor dimmer and was told in a test the SE750 did not survive the test. It might work if set to unregulated. But it might go up in smoke. Got to ask yourself, are you feeling lucky?
     
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  4. JonCarter

    JonCarter Well-Known Member

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    Need a preset board, do ya? I'm surprised nobody figured this on out yet--been standard for years.
     
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  5. Lynnchesque

    Lynnchesque Member

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    Old ones, from a company I doubt exists anymore.

    Well, okay, that's pretty much what I guessed.
     
  6. Lynnchesque

    Lynnchesque Member

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    What I need is a converter from DMX to whatever communication standard was used in the 1970s
     
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  7. Amiers

    Amiers Renting to Corporate One Fixture at a Time.

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    You are being pretty vague. You got some details. We got plenty of work around.
     
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  8. Lynnchesque

    Lynnchesque Member

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    Basically, It's an old space with dilapidated gear, so I am avoiding using any of it. But that comes with limited power distribution, 6 60amp relays. I may have to resort to snaking AC throughout the building, ha.
    Unfortunately I don't have any more details, I am not loading in to the space for a few weeks.
     
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  9. seanandkate

    seanandkate Well-Known Member Fight Leukemia

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    Options for DMX to AMX (common in the 70s) converters abound. I gather there is no existing lighting board or you want to use something more recent with a little less dust on it?
     
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  10. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    @Lynnchesque and @jfleenor Perhaps you two need to chat.
    Toodleoo!
    Ron Hebbard
     
  11. Lynnchesque

    Lynnchesque Member

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    There is an existing lighting board, a massive 2 scene preset + master control (2-3 person operated) and likely older than I am. The go-to strategy for anyone in the building is to completely avoid using it, as it may be unreliable; and fewer and fewer circuits work every time.
    I guess I shouldn't be surprised that there are indeed options to adapt... but I'm not surprised that no one in the venue has taken the time to purchase such a thing. I believe the thinking has been that this system was just about to be scrapped, all the way back to the first time I encountered it, oh say 15 years ago. The building itself came very close to being condemned recently, so it's kind of a miracle we can get in there at all.
     
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  12. RonHebbard

    RonHebbard Well-Known Member Premium Member

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    @Lynnchesque Any chance of photos?
    Toodleoo!
    Ron Hebbard
     
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  13. Lynnchesque

    Lynnchesque Member

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    I'll be sure to snap a few when we load in on the 26th!
     
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  14. JD

    JD Well-Known Member

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    Most common formats in the 1970's were analog: Many were 0 - 10 Vdc although EDI was 2 - 7.6 Vdc (Those rebels!)
    Running a dimmer off of another dimmer is almost always a bad idea. Some vendors supplied true relay or switch modules, but age might prevent you from finding any.
     
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  15. Jay Ashworth

    Jay Ashworth Well-Known Member

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    Ron is our dispatcher. :)
     
  16. Ben Stiegler

    Ben Stiegler Active Member

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    I’d load in an extra fire extinguisher and a loud BYO smoke alarm if you are gonna try the cascaded approach... spidey sense screaming “danger, Will Robinson” in the background
     
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  17. Lynnchesque

    Lynnchesque Member

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    So I'd be curious to know why exactly this is so dangerous; I've got a pretty good plug-n-play understanding of theater tech, it's the in-depth electrical engineering stuff that I don't know a whole lot about. My guess was, like any moving light, the electronics in the dimmer pack could be damaged by the dimmed power- so not a great idea. But it seems like something else is afoot? Interacting sine waves that cause the thing to explode? Magnets? An affront to the gods?
     
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  18. Mac Hosehead

    Mac Hosehead Well-Known Member

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    Powering electronics from a dimmer output can cause item to overheat. Overheating can cause release of "magic smoke" that keeps everything operating.

    Your description of the console resembles the one from my college days. It took more than one operator to work a show. It was a Century Strand system and had a 0 to -12 volt control of the dimmers.
     
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  19. Ben Stiegler

    Ben Stiegler Active Member

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    alt exploration - your final dimmer's power supply expects nice, clean 120V 60 hz sine waves without phase phiddling or leading/lagging edge chopping. Sometimes you can cheat it a little bit - like running it on a $1K Home Depot generator at a spontaneous rave ... but it really doesn't like adjustments to that sine wave. Cheap generators (and yes, dimmer outputs even when up to 100% on your control system) aren't always putting out that pure sine wave. Lamps don't care. Downstream power supplies often do. Even if you don't let the magic smoke out right away, it can cause component vibration, overheating, and other precursors of the dreaded EFS - Early Failure Syndrome.

    If you want to see for real what's coming out of your dimmer, see if you can lay hands on an oscilloscope, and monitor the dimmer waveform output first with a lamp load, and then with (if you dare) your intended load. Stare and compare - see what you learn. That's if you don't feel comfortable taking all this sage advice at face value.

    Someday I'll tell you about the very major release of magic smoke I caused which (according to bystanders) left me counting my fingers as the smoke cleared. That was a day to remember, but not to repeat.
     
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  20. Mac Hosehead

    Mac Hosehead Well-Known Member

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    Something else that you might want to investigate if you decide to power portable dimmers. House dimmer systems of this vintage and size would have a patch panel. Some patch panels had constant circuits you could patch for test and practicals. It could save you some runs of power cable.
     
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