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im wondering if there are any Digital input mods one can get for a crt projector. I see the bulb guys are using DVI and im assuming that something like DVI or SDI could help the picture- this would mean HTPCs could deliver picture with no D/A conversion at all.
 

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I like your idea but there is a couple of things you said I don't quite follow. Perhaps you can clarify for me? How would I ever get digital out of my HTPC when my Radeon video card only has a VGA output? I've heard of expensive capture cards with digital in but who makes a reasonably priced video card with digital out? How do I get digital video out of my computer.


Then lets say we do get the digital video stream to the projector, there would have to be some sort of major processing with maybe even an intel chip to get the data into the 5 analog RGB format. So it seems to me like there would always have to be a digital to analog conversion for a CRT device.
 

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1. Radeon 7500 (street about $100-120) provides simultaneous analog out and digital (DVI) out. It's an excellent card and rated tops for HT use. There are others out there (including the Radeon 8500, which appears to be getting new drivers to fix it's gamma curve issues) that do the same.


2. With any analog display technology, you'll have to do the digital-to-analog conversion at some point in the chain...the thinking is that doing it at the end of the chain (vs. the "middle") will reduce ghosting, ringing, noise, etc. that are introduced over long analog cabling runs. The Chris Stephens mod for the Vidikron Vision 1X does just this, albeit using HD-SDI vs. DVI--one cable carrying a digital signal to the projector and then doing the digital-to-analog conversion on the projector input card.
 

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It seems like Chris Stevens mod is an input card which has DVI input and would work with a Marquee 9500. True? Any idea how much it would cost and where I would get information?


While theoretically it sounds great, considering that the CRT is an analogue device, has any one found the DVI input to be visibly and substantially superior?
 

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I'm not an expert, but I'm pretty sure Chris's 9500 mod is an HD-SDI input card for the 9500, used to mate his processor of choice (the Teranex, which only outputs HD-SDI) to his CRT of choice (the 9500). I don't know if he sells the card alone or as part of his overall 9500 system (AKA the "Reference 100").


He uses an optional DVI input card for his "Reference 300" setup. DVI has some extreme length limitations and requires repeaters/amps to get it over 15' without serious image impact...HD-SDI, developed for the broadcast world, doesn't have such limitations in a typical HT setup.


Here's his website for more info:

http://www.referenceimaging.com/Products/index.htm


I think Alan here has used a similar technique for his Teranex demo room: he runs HD-SDI from the Teranex to the back of his CRT projector and uses an AJA HD-SDI -> RGBHV convertor with a VERY short RGBHV run (6"?). He has stated in past threads that he saw a pretty dramatic decrease in noise, ringing, ghosting, etc., methinks.
 

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Indeed I use HD-SDI. As the current DVI has limitations. I have played with the idea of a DVI input card but with all the change going on in the D-Theater/D-VHS world I don't want to commit DVI DAC hardware until this all gets worked out.


However I am keeping carefull track of whats up :)


I also have other problems going into the future with DVI as I want to support more serious formats like 4k at 24 ( 4096x2048 at 48I ) and DVI cannot support these formats where as the new SMPTE standard for dual link HD-SDI will.


D-Cinema will drive standards for high end projector interfaces and this interface won't be DVI.


However there will be a huge market for DVI in economical HT's.


As I have been focusing in the last 6 months on super high performance HT I have not gotten back to DVI yet. I Will however as I want to offer a killer CRT at a killer price.


As we wrap up the reviews for the high end CRT we will then offer a price catagory killer for a CRT system to the HT Mags.
 

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Chris:


Speaking of 9" CRT's and D-Theater-D-VHS, what would you consider the best interface to be?


LJG
 

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TAW's version of the 9500LC has a proprietary DVI input, compatible only with their DVD transports DVI output. So it must certainly exist in a non-encrypted form...
 
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