Supergun question -> CGA to VGA Converters

[Adderall]

Cross post from XX at NG...

I always see the GBS 8300:

http://www.ebay.com/itm/CGA-EGA-YUV-TO- ... 3cae43d640

But what exactly is the 8220?

http://joca-tech.de/Arcadeforge/product ... bsi6jrdu53

I even saw a 9800/8200:

http://www.ebay.com/itm/NEW-Arcade-game ... 2a2e31ab20

Is it just the encoder chip?

[matrigs]

if you look closely, one of them has two vga outputs, and the other one has one.

afaik there are no other differences between them.

[Adderall]

are these OK to use for a supergun, or is there a better choice out there somewhere?

[orbus]

What type of video output options does your Supergun have? There are undoubtedly better options, but most of them are likely to be more expensive. The GBS is popular because it accepts RGB and it's cheap.

[Adderall]

What type of video output options does your Supergun have? There are undoubtedly better options, but most of them are likely to be more expensive. The GBS is popular because it accepts RGB and it's cheap.

It has Component Video (JROK), straight RGB out (for PVM) and hopefully decent VGA for my work monitor in the office when I have some spare time.

[Fudoh]

With component you got really better alternatives. Any old Faroudja or Silicon Image linedoubler will perform way better than a GBS8xxx unit.

[orbus]

If the Supergun already outputs VGA, why do you want the GBS?

[Adderall]

With component you got really better alternatives. Any old Faroudja or Silicon Image linedoubler will perform way better than a GBS8xxx unit.

anything small in stature as to fit in the enclosure?

[Adderall]

I could just use my xrgb2+ as well... but was looking for something "all-in-one"

but, I was hoping to not sacrifice quality

[Fudoh]

If you strip an iScanPro from it's enclosure, the PCB is roughly 20x12cm.

[Fudoh]

Maybe you might want to use your XRGB for now and wait for Crafty-Mech's CGA 2 VGA converter board. Sounds promising.

[Adderall]

Maybe you might want to use your XRGB for now and wait for Crafty-Mech's CGA 2 VGA converter board. Sounds promising.

good idea.

thanks for the input Fudoh! We're lucky to have you here

[orbus]

Maybe you might want to use your XRGB for now and wait for Crafty-Mech's CGA 2 VGA converter board. Sounds promising.

Search the hardware forum for Retropix - that's Crafty's board. Keep in mind it's going to accept 240p only though.

I'm still a bit confused because I thought you said your Supergun already outputs VGA. Did you mean you want it to output VGA, and that's what you're looking at options for?

[Adderall]

Did you mean you want it to output VGA, and that's what you're looking at options for?

yeah.. it's not built yet. sourcing the parts for it and was confused about the different VGA converters.

[orbus]

Ah, got it. I just bought a couple IScan Pros off ebay (thanks Fudoh!) for use with PS2. They haven't shown up yet, but I'll let you know how that goes when they do.

[Adderall]

Ah, got it. I just bought a couple IScan Pros off ebay (thanks Fudoh!) for use with PS2. They haven't shown up yet, but I'll let you know how that goes when they do.

Thanks! if the crafty-mech option is too far away, I'll probably go with the iscanPro.... very interested to see how yours turns out.

[orbus]

For reference, I ended up getting two. One was 50 bucks shipped, and the other was 55. One unit is missing its power supply, so I ended up sourcing this one. Probably a bit overkill, but I felt better going with a reputable supplier than a random power brick off ebay.

[Crafty+Mech]

Ah, got it. I just bought a couple IScan Pros off ebay (thanks Fudoh!) for use with PS2. They haven't shown up yet, but I'll let you know how that goes when they do.

Thanks! if the crafty-mech option is too far away, I'll probably go with the iscanPro.... very interested to see how yours turns out.

I'm steadily working to get the RetroPix to a prototype phase so I can send out some test units for evaluation.

This past week I had to drop everything to finish the design for the mini SLG 2 (I'm approaching 250 units sold, and am just about out of boards. Instead of just reordering a new batch I wanted to take the opportunity to redesign the unit to be universal instead of split into an Arcade or PC version).

Speaking of the GBS-8200, The board's spotty performance and incompatibility (still can't get the GBS to work with a Raiden II pcb) was the inspiration for the RetroPix. The GBS does work well for the Neo-Geo MVS, it seems to be hit or miss. That reminds me, I read somewhere else there are two firmware versions floating around for the GBS, anyone know if that is true? I have the single VGA output version.

[Fudoh]

But to stay fair, it will still be tough to get a Seibu board running on your RetroPix linedoubler, since most 31khz displays just don't support refresh rates under - let's say - 58Hz.

[Crafty+Mech]

But to stay fair, it will still be tough to get a Seibu board running on your RetroPix linedoubler, since most 31khz displays just don't support refresh rates under - let's say - 58Hz.

Ah, did not realize the Seibu boards were not running @ 59-60hz! I did have luck with a Raiden board and the GBS, but definitely not Raiden II. I wonder if I should provide the option to force 60hz, even though the scrolling won't be perfect, it would get boards like Raiden II working on a VGA display.

[Fudoh]

It pretty much destroys the scrolling, so it's not what you want. Certainly an option would be a possibility, but I imagine that it's hard to implement a xx.xx to 59.94Hz conversion, without being to stuck to a few certain input refresh rates, isn't it ?

[Crafty+Mech]

It pretty much destroys the scrolling, so it's not what you want. Certainly an option would be a possibility, but I imagine that it's hard to implement a xx.xx to 59.94Hz conversion, without being to stuck to a few certain input refresh rates, isn't it ?

It would definitely only work with refresh rates that were pretty close to 59.94hz already, so probably not that useful. Which is a shame because I would really like to get my Raiden II board to work on a VGA monitor!

[orbus]

Regarding the GBS - there seem to even be several board revisions available on ebay. One seller was claiming that all of the such-and-such revision boards were counterfeit copies of the "original" Gabes board. No idea if that's true, or a ploy to drive up his own sales.

That was definitely one thing that turned me off the GBS solution though. You drop 50 bucks on ebay, and you really have no idea what you're going to get.

[Fudoh]

But you would need a frame buffer to do that. How else would you be able to repeat a full frame in order to apply the framerate conversion ?

[Crafty+Mech]

But you would need a frame buffer to do that. How else would you be able to repeat a full frame in order to apply the framerate conversion ?

No framerate conversion, just fudging the vsync and altering the input buffer timing. Crunching the rough numbers, the input limit would be about 59.5hz given the line buffer size I'm using (two lines of src input). So probably not really that useful if boards like Raiden II for instance are running at below 58. And I'm definitely not interested in frame buffering, so that is off the table.

[Fudoh]

right. And I think a 100% perfect input timing = output timing is your biggest plus (aside from sheer picture quality). Many of available linedoublers output to 59.94Hz no matter what the input is and that causes more problems than it helps. VGA inputs usually handle 59.xx to 60.xx just fine.

[Crafty+Mech]

right. And I think a 100% perfect input timing = output timing is your biggest plus (aside from sheer picture quality). Many of available linedoublers output to 59.94Hz no matter what the input is and that causes more problems than it helps. VGA inputs usually handle 59.xx to 60.xx just fine.

That is a good point, I am aiming for broad compatibility, but not if it compromises the picture quality. Any other 15k progressive sources off the top of your head that are also problematic because of sub-60 vertical refresh rates?

[Fudoh]

Not really. MVS (59.15Hz) in general pretty much maxes out the displays compatibility. On *most* displays it works, but there can be hickups caused by internal framerate conversions already. Anything closer to NTSC specs usually works fine.

I think the only other thing you have to watch out for are the limits of the actual 480p SMTPE timing (or VGA VESA). What you *need* on the output is a 480 line signal (plus front/back porch, sync pulse width and so on) with variable vertical refresh rate (locked to the input refresh rate). 15khz CGA comes in many flavors. I think it starts with 192 visible lines (Sega System E), a lot of stuff with 224 lines (CPS1/2/3), 240 lines (Cave SH-3), but up to 256 lines (Irem M82).

If you take a System E board and double it's active lines you get 384 lines, but you need a 480p timing, so the output needs to be padded on top and bottom, same is true for 224 lines. I don't know how the 15khz timings of those boards look like, but I think the padding is created automatically because it's present on the 15khz signals already - otherwise those sources wouldn't work on existing linedoublers (but they do). All linedoublers and scalers (except a single one) cuts the M82's 256 lines down to 240p and outputs a 480p signal. The Micomsoft Displ is the only one to output 512p54, but I personally think that this causes more problems than it brings benefits.

[orbus]

So my iScan Pro turned up today. Have not had time to test extensively, but so far I'd say it's... okay. Picture is a bit soft, but that's to be expected with upscaled 480p. I popped Third Strike in the PS2 and played with it a bit. Looks good, but there's very obvious comb artifacts present on a number of animations. I also noticed a slight input delay, which is unfortunate but to be expected. Adding an SLG would probably improve things noticeably on the picture front.

[Fudoh]

obivously it's 240p material with which a processor like the iScan Pro triumphs over a GBS (because 240p recognition is what the GBS's missing). Testing it with an extremely bad conversion like SF3 (a 384x224 title running emulated on a 720x480i output) is beside the point.