Film-Tech Forum ARCHIVE: Kelmar PS instead of a Component Engineering?

This is topic Kelmar PS instead of a Component Engineering? in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Bill Duelly (Member # 3612) on 03-26-2016, 02:41 PM:

I have a Component Engineering LED setup in my rca sound head. Its recently developed some sporadic humming that does NOT seemed to be related to any wiring or connections. I want to swap power supplies to see if that is the culprit, but I only have a Kelmar ps. Can i use that instead of the CE power supply? If so, what do i do about the ground connection that the pre amp is looking for? Leave it unconnected or tie it to the - ?

As always, Many thanks for input!

Posted by Mark Gulbrandsen (Member # 72) on 03-26-2016, 06:03 PM:

You can but it seems that the grounding is different. I reccomend you compare schematics first. I have done it in the past but it was a long time ago. Personally, the C.E. Supply is the better of the two. And I would just fix it.

Mark

Posted by Steve Guttag (Member # 268) on 03-26-2016, 06:28 PM:

I'd be amazed if it was the power supply. I've put CE supplies on Kelmar readers without an issue.

As for grounding...only the preamp power gets a ground reference to the reader board. The output should be referenced to the sound processor ground. I always floated the shield at the reader output but run a dedicated ground wire between the reader and the sound processor.

Posted by Mark Gulbrandsen (Member # 72) on 03-27-2016, 10:10 AM:

I have had CE supplies die in past years, but way more Kelmars does than CE. The CE is also a current regulated supply and that is more desirable.

Mark

Posted by Bill Duelly (Member # 3612) on 03-27-2016, 08:47 PM:

Thank you all!

I connected analog led output from the kelmar ps while maintaining the preamp power output from the CE. Left on for 2 hours and ran a reel and no hum issues. So i'm getting replacement CE power supplies then.