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Author Topic: Connecting EUMIG to Amplifier
Michael De Angelis
Phenomenal Film Handler

Posts: 1261
From: USA
Registered: Jul 2003


 - posted September 01, 2003 02:28 AM      Profile for Michael De Angelis   Email Michael De Angelis   Send New Private Message       Edit/Delete Post 
Dear Friends,

I have a film friend that formally collected 8mm. Today he strictly collects 16mm. During that time he solved the "hum" that emanates during playback.

He emulated the "hum sound" by playing a series of similar octave sounds on his trumpet, recording it for playback for another friend that specialized in electronics.

His friend isolated the tones into electronic filters using a notch switch, ultimately
connecting the unit and selecting the filter that matched his machine and knocking out the hum during playback. Nevertheless, it worked.

I do not know if the switch was a type of potentiometer linked to circuitry.

Unfortunately, he disposed of the unit over 20 years ago.

Maybe there is musician and an electronics buff, that can configure this type of unit again.

I know that I would pay for a schematic of this type of unit.

Best,

Michael

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Isn't it great that we can all communicate about this great
hobby that we love!

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003


 - posted September 02, 2003 10:58 PM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
I think the ultimate way around this could be a feed forward circuit. Basically what this does is what the hum correction circuit is trying to do. It would take a sample of the line voltage and run it through an op amp circuit set up to subtract the sample out of the audio output signal. This would be fed into the input of the power amplifier. Since the amount of line frequency signal subtracted out would be fixed, it would not effect low frequency signals that are supposed to be there.

Any good analog designers out there? I might have been able to do it at one time but for the past 4 years I've been scribbling proposals!

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All I ask is a wide screen and a projector to light her by...

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Henry Perangelo
Film Handler

Posts: 33
From: Durham, NC
Registered: Jun 2003


 - posted September 03, 2003 11:04 AM      Profile for Henry Perangelo   Email Henry Perangelo   Send New Private Message       Edit/Delete Post 
I vote for using an equalizer to filter out the "hiss". I know some of you purists may protest, but it very simple, safe, and does the job without much signal loss and without much fuss!

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Tim Christian
Expert Film Handler

Posts: 219
From: Norfolk, UK
Registered: Jun 2003


 - posted September 23, 2003 11:34 AM      Profile for Tim Christian   Author's Homepage     Send New Private Message       Edit/Delete Post 
This is my solution to the connection problem:
connector box

Amplifiers with graphic equalizers can be set up to the required equalization or noise filter properties.

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Tim

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