Hi-res 31Khz across DC revisions

[CD AGES]

Has anyone out there done any research on video quality (specifically the native 31khz) comparisons across all 3 of the system's hardware revisions (0,1,2)?

Asking since thru some random trail and error, I've discovered that Rev 0's may have poor video quality in VGA mode compared to its Rev 1 counterparts. The former appears to experience quite a bit screen artifacts (/Noise?) on screen. Tried a total of 3 Rev 0 models (2 JPN and 1 US) and 2 Rev 1 models (both US) and the results have been on point so far.

Anyone care to elaborate further or have any additional information on this?

[mstar]

Hm, i only have one VA0 PAL Dreamcast and a VGA Box, but sadly no others to compare against

FWIW, i didn't spot anything out of the ordinary regarding picture quality - but as i said, i've no possibility to compare it to a VA1/2.

Do you maybe have screenshots for comparison and/or to show what to look for?

[CD AGES]

Hm, i only have one VA0 PAL Dreamcast and a VGA Box, but sadly no others to compare against

FWIW, i didn't spot anything out of the ordinary regarding picture quality - but as i said, i've no possibility to compare it to a VA1/2.

Do you maybe have screenshots for comparison and/or to show what to look for?

What model or Brand is your VGA box?

I can try. Keep in mind, the screen that I use for these tests is a 27' ASUS LED monitor (same ones used at major fighting game tournaments).

This all originally came about after having purchased a Kaico brand HDMI Adapter. I haven't been too happy with the latest model of the Pound HDMI Adapter I previously own (the colors don't look right and the overall image looks tad blurry). I kept hearing the Kaico HDMI provided better results and to my surprise, it does. It almost looks on par with the system's native VGA output quality (mind you I've tested other brands of the same product and they are terrible).

When I use the Kaico on all my VAO systems, it produced some faint yet fairly visible vertical lines across the entire screen. But not when I'm using it on some of my VO1 systems. At first I though maybe it was the cable itself (and it could very well be). So I decided to test one of my older generic VGA cables and it produces similar results tho not as profound. Since I do own an Official SEGA VGA box I decided to test that as well, but produces an excellent picture quality across all hardware models.
So... perhaps it's not so much the hardware itself, but how these 3rd party video cables are being designed?

[mstar]

It's a retro.bit branded one, however iirc those are available from various brands - it's one of those in a translucent PMMA shell

[CD AGES]

That's one of the few VGA cables I do not own. Tho they are still readily available and quite common, I hear they aren't always the best in terms of build and video quality, tho I have seen some that work just fine. I'm sure it simply depends on the manufacturer.

[SEGA RPG FAN]

Playing on a PC CRT monitor I haven't noticed any difference between my VA0 and VA1 picture quality wise. I'm VERY sensitive to video noise and artifacts. It's possible the signal timing on the VA0 is just slightly different, causing sampling artifacts on the adapter. That wouldn't show on an analog display.

[Alex_DC]

I do wonder if some of these artefacts are power supply noise, particularly if the caps on the power supply are not at 100% with age, or if Pico-style PSU replacements are being used.

[CD AGES]

Playing on a PC CRT monitor I haven't noticed any difference between my VA0 and VA1 picture quality wise. I'm VERY sensitive to video noise and artifacts. It's possible the signal timing on the VA0 is just slightly different, causing sampling artifacts on the adapter. That wouldn't show on an analog display.

Interesting. Yeah I imagine that it wouldn't. I do have an analog CRT monitor to check at least some of these 3rd party VGA cables I own since the monitor doesn't support HDMI. I appreciate the feedback.

I do wonder if some of these artefacts are power supply noise, particularly if the caps on the power supply are not at 100% with age, or if Pico-style PSU replacements are being used.

Hmm, I hadn't even thought about that. Its certainly a possibility. I certainly don't have any DC with a Pico-style PSU replacement. Tho I'd like to someday for reasons like these and then some.
Thanks for the reply.

[mistamontiel]

Not much if any ta add jus I do realize my rev0 takes an extra second to beam the RGB-ala-VGA picture compared to my 1

EDIT: Curious note, is SCART/JP21 able to push 480 progressive scan? Native..?

[megavolt85]

EDIT: Curious note, is SCART/JP21 able to push 480 progressive scan? Native..?

no, only interlace (15 kHz)