12k Noise With EB

T

tommygdawg

New member
Howdy all

I just picked up a used CMC Silver Bullet 12k (I believe made in 1994). I got it with a used Arri 6/12 EB and a used magnetic ballast. After trying it on both ballasts, I was surprised to find that the globe is much louder on the EB than the mag ballast. Even when the EB is set to 60hz, the globe makes a pretty decent hum that sounds very much like when I set my other HMIs to flicker free.

Thoughts on this?

Thank you!
 
The same happens with my 1.2 LTM Fresnel. Very normal.
You will discover advantages and negatives to both ballasts.
EB is WAY more portable and a bit brighter, while mag is way more reliable (will work even in very hot weather) and potentially more quiet with DE bulbs.
 
Well, a 12k is a really big light, perfectly normal for it to make more noise than one that's smaller. And in most cases, perfectly fine since it's going to be pretty distanced from talent.

Age of the lamp could be a factor also. Older lamps have a longer electrode gap requiring more current, generating more noise. Older EB could make a little more noise than a newer one too.
 
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