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 Post subject: Video AMP help
PostPosted: Oct Sun 04, 2020 11:28 am 
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Joined: Sep Sun 27, 2020 9:28 am
Posts: 3
Is there a small fully DC coupled video amp that can take a standard NTSC composite video signal and either increase its output (variable gain would be preferred) or convert the video to a differential signal? stereo mix for windows 10

I'm looking for a complete unit not a circuit or kit.

Last edited by heywantgold on Oct Mon 05, 2020 9:34 pm, edited 1 time in total.

 Post subject: Re: Video AMP help
PostPosted: Oct Mon 05, 2020 2:17 am 
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Joined: Aug Thu 12, 2010 6:25 pm
Posts: 417
Location: Durham, NC
It might be possible to find something, though it does depend a bit on what you're trying to do, and with what.

A "standard NTSC composite video signal" is 1 volt from sync tip to peak white when terminated in a 75 ohm load. If your source supplies that "honestly" (with a 75 ohm output impedance), and your load is a high impedance (more than about 1K ohms), then you've got a 2 volt p-p signal available without doing anything. (Video quality might suffer a bit in that scenario.) Not all video devices, particularly consumer types, will do that, but almost all broadcast quality units will. Many broadcast quality sources and Distribution Amplifiers (DAs) were DC coupled as well, but not all. I'd guess that essentially no consumer grade and many "professional" grade video sources (or loads) were DC coupled.

I have seen converters that would convert composite video to differential format to drive twisted-pair (CAT-5?), but these are pretty recent things and I suspect the signal level is below 1Vp-p. No idea if they're DC coupled either.

What are you trying to achieve, and what sort of equipment are you working with?

Mark Nelson
A collector of TV signal boosters and UHF converters -- God help me!

 Post subject: Re: Video AMP help
PostPosted: Oct Mon 12, 2020 1:30 pm 

Joined: Nov Wed 30, 2016 7:35 pm
Posts: 8478
Location: Sunbury, Ohio 43074
A video amp for a stereo mix for a computer? I'm not quite sure what you're asking for. A video amp, a single ended to balanced converter, or a stereo amplifier ???

If you are just looking for a DC coupled VIDEO amplifier yes, there were some available back in the day. The trick would be finding one today. I really don't recall if they provided a balanced output, but you could always add a passive balun on the output. As noted, we need to know a lot more about your intended use...

A bit more clarity on the question please. :)

Preserving the hist. of electronics, one boat anchor at a time! :)

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