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Powergems ballast hum


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#1 Michael LaVoie

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Posted 26 January 2008 - 09:08 PM

So, I just picked up a used 1.2 Strand Par with a Powergems 575/1200 FF electronic ballast. I'm just wondering how loud that ballast usually is because, it's louder than my magnetic ballasts on my Sunburst 575's.
I was under the impression that an electronic ballast meant a relatively quiet ballast. This thing is like a lawnmower. Does this mean it's dying or something? Any thoughts are welcome.
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#2 Kevin Zanit

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Posted 27 January 2008 - 03:20 AM

Electronic ballasts in flicker free mode are known as especially noisy, much nosier than a magnetic ballast. That said, I would not liken the sound to a lawn-mower, its usually a high frequency noise that sound guys love.
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#3 timHealy

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Posted 27 January 2008 - 10:03 AM

return it and get your money back.

the only noise you should really hear is a high pitched wine. the kind that kevin mentioned. but it comes from the head in flicker free all the time mode as the sine wave is chopped. actually, as i understand it, flicker free ballasts are flicker free all of the time, but in silent mode it is flicker free from a small range of 20 to 30 frames per second or so. flicker free mode for the rest of shooting ranges.

the ballast should be "relatively" quiet. but you wouldn't want larger ballasts right next to the actors and sound. could there be a damaged cooling fan rubbing up against something inside?

best

tim

Edited by timHealy, 27 January 2008 - 10:05 AM.

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#4 Chris Schlaghecke

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Posted 31 January 2008 - 11:38 PM

return it and get your money back.

the only noise you should really hear is a high pitched wine. the kind that kevin mentioned. but it comes from the head in flicker free all the time mode as the sine wave is chopped. actually, as i understand it, flicker free ballasts are flicker free all of the time, but in silent mode it is flicker free from a small range of 20 to 30 frames per second or so. flicker free mode for the rest of shooting ranges.

the ballast should be "relatively" quiet. but you wouldn't want larger ballasts right next to the actors and sound. could there be a damaged cooling fan rubbing up against something inside?

best

tim


You beat me to it Tim, I would seriously look at the fans in the ballast, that is probably one of the only areas in the powergem ballasts that can make the kind of noise that Michael is describing.
Check to see that it hasn't been dropped at some stage and that the fan is not hitting the casing. Alternately it could be the bearings, which is not so easy to fix, but if all else fails try some lubricant spray on them, preferably after removing the fan from the ballast!

Michael, if you still need help PM me and I can shoot you the email address of one their UK service techs. The powergem guys are dynamite about their aftersales support. I have been in a couple of tight spots and they have been most forthcoming in their help. At ALL hours of the day!

Make sure you let your rental shop know about it so that they can A: fix it. and B: perhaps do something about your rental bill......

Off topic a little......I have noticed lately that I get a large amount of ballast squeal from powergems if I am using a double ended lamp, especially in a strand 2.5K Hmi softlight. Anyone else noticed this?


edit: fixed typos

Edited by Chris Schlaghecke, 31 January 2008 - 11:40 PM.

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