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Discussion Starter · #1 ·
I'm thinking of buying a used 4-1 Extron RGBS switcher to automatically switch YPbPr signals. The only problem is, the Extron uses the S channel for autoswitching purposes, and its S inputs will NOT pass a video signal. According to the manual, which I downloaded from Extron's website, in order to autoswitch YPbPr sources, you need to use a T connector to split the Y channel and feed one of the splits through the S input. I realize that anytime you split a signal some degradation will occur, but I'm wondering if splitting the Y channel like that will result in a perceptible difference in picture quality. The cable connecting the switcher to the display will most likely be about 3-4 feet.


I'd buy the 2-1 Inline switcher, but I need to switch 3 sources.
 

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Shouldn't really be a problem. Make sure the video (Y input) is last in line, If you keep the extra cable less than a couple of feet long, it won't affect the picture.



Bob Smith
 

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Discussion Starter · #4 ·
I was just wondering... Since I'll only be using the S inputs on the switcher for autoswitching, is there any reason I can't just feed any signal into them (say a composite video signal or even an audio signal) as long as they turn on and off in unison with the corresponding YPbPr signal?
 

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I don't really know the internal circuit of the detector circuit, I'm assuming just a level detector with a relay driver.


Composite video would work just fine. Not sure about audio. If the output is latched, that is, if once it detects a signal the relay stays activated until another input comes alive, it might work, but even then I doubt it. Audio signals have tremendous range, and may be quite a bit below the 1 Volt peak to peak signal video provides, so I doubt it would be reliable.


You might have to wait for a commercial to have enough audio level to make it switch!


Bob Smith
 

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Discussion Starter · #6 ·
Thanks again, Bob. As far as the audio signal goes, I was thinking more of something like white noise or a test tone, although I'm not sure how I'd implement that! I guess I was mainly just trying to confirm that any consistent signal that's turned on and off at the same time as the video source would work for autosync purposes...
 

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It would be nice if video switchers had a sixth 75 Ohm input, so you could switch the digital audio that is usually associated with HD sources.


Bob Smith
 
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