Nonstandard frequency support (EGA, VGA, amiga 'doublePAL', etc) - AVS Forum
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post #1 of 6 Old 07-30-2013, 02:11 AM - Thread Starter
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I'm curious if anyone can offer some suggestions or information about how well CRT projectors support various multiscan type frequencies of the 80's to 90's era...

I'm a big fan of retro computers and arcade game emulation, and many of the display standards of that era do not map up or look real good on 'modern' LCD type displays, or locked to a 60hz refresh... i'm interested in running at least between 50-76hz (and not necessarily only 50, 60, 75... there are some oddballs like 56 and 58) as well as the varying resolutions which were around in the 16-32 bit computer era on a big screen. I was wondering how hard it would be to find a compatible CRT projector that's truly multisync like this (just a range of variable supported frequencies, instead of a few hard fixed standard locks like say only NTSC and VGA).

Extremely high resolutions aren't very important, even 720p ability is not essential, though ideally some SVGA frequencies would be possible like 1024x768, possibly even higher, i'm not quite sure what all has been out there in the past.


Oh, and although i'm not seeking home theater resolutions, I am seeking more like home theater quality if possible - deep blacks, good contrast and the rest. Not just a data class projector only useful for boardroom text. I'm seeking a retro-ready projector to be alongside an LCD HD projector aimed at the same screen, for better reproduction of challenging content.

Extreme light output is not needed - because of the pixel burn problems of CRT's unless someone had a magic fix for high light output without the danger of that. I'm just accepting i'll have to project a smaller image for a given light output.


Where would you suggest I start my research and are there others doing similar things?
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post #2 of 6 Old 07-30-2013, 06:15 AM
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Unlike digitals, CRTs are not limited to set resolutions. you need a data grade CRT though, as video only units will only project 480i, and computer resolutions are past that. The only limitation that data grade CRTs have is the max resolution you can feed it, but I don't think any of your sources will do higher than 720p, so you're fine that way with almost all data grade CRT projectors.

Also, some CRTs will only accept negatiive sync, and none of the later data grade CRTs will accept a TTL level input, so you need to make sure what you feed the set is at a video level (1Vp-p down to 0.7v p-p), and you will be fine.
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post #3 of 6 Old 07-30-2013, 09:04 AM
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post what city your in and we'll help you scour craigslist. Basically, any 8 inch EM focusing set will give you what you want and more with pretty darn good light output up to 92" wide screen. Electrohome marquee,sony G70 or 90,NEC PG or XG series (runco 980 and higher),all of these would be a good choice. Tube condition is critical though,don't buy burned tubes .(some light shading is OK).

http://www.curtpalme.com/Projector_Rankings.shtm

If CL is a bust, check with Curt Plame for a warrantied machine or on Videogon.com . Videogon will at least have people who re hobbyists and know something about their machines as opposed to rolling the dice on flea bay.

http://cgi.videogon.com/cgi-bin/fs.pl?projcrta
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post #4 of 6 Old 07-30-2013, 01:17 PM - Thread Starter
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Quote:
Originally Posted by Curt Palme View Post

Unlike digitals, CRTs are not limited to set resolutions. you need a data grade CRT though, as video only units will only project 480i, and computer resolutions are past that. The only limitation that data grade CRTs have is the max resolution you can feed it, but I don't think any of your sources will do higher than 720p, so you're fine that way with almost all data grade CRT projectors.

Also, some CRTs will only accept negatiive sync, and none of the later data grade CRTs will accept a TTL level input, so you need to make sure what you feed the set is at a video level (1Vp-p down to 0.7v p-p), and you will be fine.

Oh wow, first Bill Fitzmaurice, and now Curt Palme responds, this is so cool, AVSforum really is the place. biggrin.gif I know of both you guys from your websites and you under the book mark 'THE guy for CRT proj info' that i'd found so far even tho I haven't read enough of your site yet just marked for later.

To share a bit more info to help focus things:

I'm aware of the not limited to set resolutions bit, it's why i'm such a big fan of CRT's in general. The system i'm planning for the future is going to have a 36-40 inch direct view CRT (for daytime windows open watching, and things like video game light guns which just wont work otherwise) and then a pair of drop down screens in front of it (one for 2d, and one higher gain for 3d), which i'm planning to have both a CRT projector for as well as a DLP HD type projector. (eventually a 2160p one when they come out, which with pixel doubling and tripling will match pixel perfect any HD signal I feed it currently)

The job of the CRT projector will be for giving a nice big image to "any retro source I can think of" from SuperGun connected arcade boards (which can have oddities, like japanese shooters have things like 56hz, others push 53hz) to 16 bit computer era stuff, including some oddities like the Sharp X68000 which has a 1024x1024 square pixel mode on 31khz and eventually up to 2048x1536 on SVGA computer modes, with plenty of brightness would be ideal but I don't have to get there immediately, figuring out an upgrade path to go up in steps is allowable. I don't have a handy list but there's nonstandard modes (not mapped to SVGA) like Macintosh's 852x480 at 75hz, atari ST's 640x400 at 70hz (i think), amiga has a 1440x582 overscanned PAL-mode at 50hz plus some odd modes in general http://www.amigahistory.co.uk/resolute.html - it's mostly important that the projector not lock into only CGA/EGA/VGA standard frequency. Approx budget i'm hoping to find something in maybe $300-500 for a projector range, more possible but would need a really compelling reason. Less is fine if something does everything I want for now, with plans to upgrade to top of the line later. (like a Cine 9) I don't have to hit every top res right away because although the higher resses are supported they are uncommon for games so even a 7 inch costing $150-200 maybe, just doing everything up to 40-50khz may be fine to start if there's a good deal. Next step for 62khz which I think is what the output of flicker fixers for AGA Amiga's at top res (rarely used in games so lower importance) ends up being. Just projecting from a CRT at all looks so much better for older content.

As an odd question, can a CRT projector be run on it's sideways/producing a vertically oriented "3:4" portrait image? : P I'm guessing no but just curious...

Whats the highest refresh rates a CRT projector can run, even if at lower resolutions, are they like CRT directviews that can run 100-120hz (for LCD shutter 3d)?

Quote:
Originally Posted by draganm View Post

post what city your in and we'll help you scour craigslist. Basically, any 8 inch EM focusing set will give you what you want and more with pretty darn good light output up to 92" wide screen. Electrohome marquee,sony G70 or 90,NEC PG or XG series (runco 980 and higher),all of these would be a good choice. Tube condition is critical though,don't buy burned tubes .(some light shading is OK).

http://www.curtpalme.com/Projector_Rankings.shtm

If CL is a bust, check with Curt Plame for a warrantied machine or on Videogon.com

Thanks for the suggestion. What is special about 'EM focusing'? Do you think I be able to get a 'theater standard' (i'm told) 16 footlamberts at 92 inches without adding screen gain, or should the black level of CRT's let me get away with a bit of screen gain while still having an absolute blacker than black? Is Curt's list pretty much definitive or are there other projector makes of modern era out there?

I'm all over Minnesota and the eastern dakotas with regular driving, but i'm willing to travel out of area to pick up a machine if needed which also lets me personally inspect something. If cost for freight compares to gas on my economy car i'd rather drive. Willing to drive to chicago or des moines or rapid city or bismark for instance. I just don't want to drive 1000 miles and have it sold out from under me normally so wont craigslist too far away. Heck willing to drive out of the way to potentially much of the US during 2-3x a year usually in summertime road trips I take. And actually at the moment I wasn't looking to purchase immediately, I was hoping to educate myself a little more on understanding what is what and how to judge. Plus I might want to get three. smile.gif

It's entirely plausible that if I go a little 'crazier' with my ideal setup I might be wanting three matching CRT projectors instead of one for a retro-triplehead gaming setup, and I want to know more about what potential additional issues might be caused by doing so, if any. I'm not seeking to spend thousands on edge matching software (i'm not that hardcore or wealthy, just passionate) but I may want to pick a projector that shows up more commonly/reliably on the market since the one to start would very likely become three, and if I ever had to replace one of the three to match models i'd want it to be not as hard. (whereas a single projector person could just change models if the original crapped out, i'd likely still have two still working ones) I've also no clue whether there's any projectors more suited to multiprojector situations (geometry adjustment near corners maybe?) but i'm curious whats out there.
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post #5 of 6 Old 07-31-2013, 01:06 AM
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Wow a lot of questions in your last post, I'll try to answer some questions.

- Can CRT's be run sideways

They certainly can, some brands even factory-made some vertical unites



Do pay attention that turning a normal horizontal CRT sideways means that you lose some adjustements since they are fixed to the horizontal orientation. Best would be to turn all the tubes 90 degrees.

- Max refreshrate

Depends on the projector, i have run my 808 at 720p 120hz just to experiment, however you might experience some ghosting on the green tube (P43 phospher fixes this but has other disadvantages)

- Why EM focussing

You can read about the difference between EM and ES focussing on curt's website http://www.curtpalme.com/CRTPrimer_12.shtm

Main advantages:

Nearly no loss of focus as the tubes age
Better focus possible

A remark i have

I tried several resolutions on my 808 + a 90" 16:9 screen. The scanlines on 480P were quite big, even on 720P quite visible. Make sure you consider this smile.gif
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post #6 of 6 Old 07-31-2013, 08:54 PM - Thread Starter
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Yeah, silly me I realized several of my questions were answered by Curt's CRT Primer, I just hadn't been back there to read yet. I bookmarked it, took notes at the time, lost the notes, and forgot what I learned last time. :^)

If they can be run vertical, even if sometimes involving rotating the tubes (is this difficult?) that's good... the possibility of having separate projectors for horizontal vs vertical orientation is there, for that matter because of 'portrait' format arcade games, and portrait format multihead PC gaming using these as monitors. (where the screens get so wide with 3-5 projectors it starts to make more sense to have taller than wide segments)

I'm told I may have substantial cooling noise issues if running multiple projectors in one location, I was considering running dedicated extra AC ducts to the center of the room under the floor to pipe into the fan inputs of whatever projectors I use, and probably dedicated outlets for wherever the heat-out vent is if I can capture it (the plan to do this may alter which projector I use, some may have a distinct heat 'exhaust' and others may let it out any which way, i'm not sure), which I was hoping would make it quieter to boot or let me run a stock or modified/replaced internal fan at much lower speed... are CRT projectors any hotter per lumen than DLP's let alone older light inefficient LCD's? Alternative multi-projector quiet cooling solutions are welcome...

P43 phosphor information may then be very important to me as I was hoping for a 3d capable experience using shutter glasses.. what are the advantages and disadvantages of the P43 tube and which projectors is it used on? Approximately what refresh rate does it become an issue that i'm forced to pick one way or another, 80hz? 100hz? I haven't yet decided how important 3d is to me, I just want to know my options.


Scanlines are okay, even desirable for some configurations (many retro gamers actually prefer them, i'm fine either way/emulators often interpolate or upscale if wanted), the use of the CRT projector will not necessarily be for all content in my case, and my original spec planned to have a separate DLP projector for if I was running an emulator or line tripling on a lower res source. The CRT may be set up for a smaller displayed size than the DLP in that case. (or at least less width, like CIH but only for 4:3 CRT and 2.35:1 DLP setups with the DLP being when 4k projectors become affordable so if I crop to 16:9 on the display I still have plenty of resolution) The multiprojector triple head option would have two side screens to pull down which mask the center screen at about 4:3 anyways (or 3:4 if I go the portrait route). I'm basically planning what I call a multitopography projection setup, where the sizes and positions/angles of the screens is not only one fixed format, and more than one projector is used and what seems redundant (in having more than one projector aimed at the same screen) setups optimized for different uses. The side screens might matte the main one at 3:4, or 4:3, or 16:9 and might be at a 30 degree angle, or a 45 degree angle depending on source format (different fields of view in different PC games), or a "0" degree side by side if all the side screens are left up. (the whole wall painted with a paint suitable for being a screen or given an oversize screen on the wall behind) Therefore the side screens will have to be mounted on tracks that let me change the position and angle, unless they are inexpensive enough (i've seen some improvised screens that work surprisingly well just out of white vinylish fabric) to just have drop down screens in different positions. The side projectors will have to move too if more than one screen angle is projected upon. Because i'm hoping to experiment around with robotics and motorization projects while in college, the whole setup may even be motorized so that one push on a touch screen sets the display topography for the source, moving screens, moving projectors, sets the masking, turns on the right projectors, and routes the preferred triplehead video signals..

And if you think that's nuts wait til you see my planned speaker array or set of AV sources which feeds into it. : P (http://pseudomacro.wordpress.com/2012/04/29/petes-collection/ is approaching the ballpark)
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