What is the best way to connect VGA to 15KHz monitor?

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    • What is the best way to connect VGA to 15KHz monitor?

      Hi,

      I've seen a couple posts about 31KHz to 15KHz connections and, as I have my own doubts about it, so I'm opening a new thread

      What a want is to connect my emulation computer from VGA to PVM monitor, and also, for connecting original PCB's too, like Naomi...

      Right now, I'm using an UMSA interface from ArcadeForge

      Lately, I'm becoming a real fan of Extron products, so I'm wondering If there is some Extron interface I can use to connect my VGA devices to the PVM in the best possible quality

      hanks in advance
    • you mean without conversion / scaling right?

      Any Extron Crosspoint switcher should be able to do it.... they support pretty much everything as input or output.. like RGBHV (VGA), RGBS, RGsB, Composite, S-Video.. whatever.

      You just need to take care that the input matches with the output (or add scalers in the chain)
      LOAD "*",8,1
    • your sentence can be a little bit misleading.. you can't output 15khz from a 31khz input without downscaling.

      What you can do is to output RGBs (for example SCART) from a RGBHV source (= VGA), but the souce frequency needs to be always supported by the output device.
      LOAD "*",8,1
    • Nodoyuna wrote:

      Yes, I'm looking for a solution without downscaling, just a device to Connect 31KHz to 15KHz monitor
      I'll try the Extron 203rxi
      If your monitor can display 31khz, but only has a classic 5pin connector (R,G,B,sync,ground) you could use a Extron 580i to composite the H and V syncs safely.
      I guess some of these style chassis do exist in the wild?
      I would suspect the image would be dark without some amplification on the RGB lines due to 5pin connector expecting JAMMA levels of power?

      The thing you seem to be failing to understand is IF that monitor is truly a 15khz monitor it won't display a 31khz input.
      That's why we have dual syncs (15/24khz) and tri-syncs (15/24/31khz)... But not me cuz CRTs are dead man *snicker* anyway... ;)

      CGA=15 EGA=24 VGA=31 you can think of it like this.
      Each format is different, and needs to be supported by the monitor if no scaling/conversion is used.

      deibit wrote:

      the souce frequency needs to be always supported by the output device.
      Hey you said it using less words, no fair. :D
      Darksoft/Apocalypse: CPS2, CPS3, F3, MVS, S16
      RGB: RECO v2
      invzim: Jammafier v1.6b
      XianXi: JNX Raiden, SC Taito Classic, SC Sega System 16/24, Namco System 11/12 KHA
      Frank_fjs: JAMMA Extender (Special HAS Edition)

      The post was edited 1 time, last by jassin000 ().

    • Hi

      What I have is a PC with the CRT Emudriver installed on the VGA output

      If I use a VGA to SCART cable to Connect this output to the 15KHz monitor, the image does have interference lines

      Then, I tried the UMSA device, and that's how I use It now, but the output image IS mostly blurry, so I think there should be a better method to get the BEST output

      So, is there such a device?

      Thanks
    • What is your PVM model? As long as you have CRT emulator out putting to 15khz you will be fine with the Extron that I mentioned..

      On my PVM 20L5 --> RGB output connected to BNC cable RGB and black sinc --> going to Extron --> VGA cable going to PC running GroovyMame CRT emulator at 15khz.. most of what I play is 15khz.
      The Future Is Now
    • That one is 15khz only.. on crt emulator you will need to set up to 15khz.. I am not sure if that monitor had no problems combining the sync so you might want to try a Cable with a BNC to one end and a VGA on the other end. If that does not work then the Extron..the Naomi you will have to set it to 15khz and connect to the Extron.. anything 31khz like Xbox 360 you will need a downscaler to conver 31khz (Xbox 360) to 15khz so your monitor will see that.

      Edit - that monitor has the RGB pins (25 or 31) and no BNC RGB.. you might need a special cable and maybe retro console accessories can make one for you with one end for that special pin and the other end for BNC so it can go into the Extron.. you might need to switch between your RGB consoles and the Extron or get a gscart switch with VGA output that can go into the Extron but that will cost you like $200
      The Future Is Now

      The post was edited 1 time, last by SNK-NEO-GEO ().

    • if you are using a PC you can soon also consider using a VGA 31khz monitor to use 240p without any added device.

      Some of them are cheap and almost same quality as high end PVM or BVM.

      I always thought a 31khz couldn't do 240p, but I was wrong, it depends also on the refresh rate.

      If you play emulation, you can double the refresh rate from 240p60 to 240p120 a 31khz monitor can show 240p with proper scanlines.

      The trick to make 240p enter the range of 31khz is to use an emulator that can handle double frame, or black frame insertion. It does 120 frames / s instead of 60 frames /s either by sending twice the same frame or adding a blank frame. The second solution creates a dark tint because half of what you see in a second is a black frame.

      Retroarch will soon integrate 31khz 240p option, as Ben Templeman is working on that solution.

      I guess the same can work with Groovymame but I haven't experienced this yet.

      youtube.com/watch?v=TGmLRuHFvRM
      Any Multi MVS bug ? Before asking delete BUFF FILE on the SD card and Reset NVRAM procedure : Power on without cart, Press Start multiple times until it asks to press ABC + Start, Do it, Power off > Done
    • archimage wrote:

      The trick to make 240p enter the range of 31khz is to use an emulator that can handle double frame, or black frame insertion
      Yup double striking beams with black frames inserted will do the trick.
      I still wouldn't really say its 240p tho, because naturally 120 fps isn't spec.

      It's always personally strange to me when people strive so hard for proper refresh/sync/output on a emulation setup...
      But I guess to each his own? :huh:
      Darksoft/Apocalypse: CPS2, CPS3, F3, MVS, S16
      RGB: RECO v2
      invzim: Jammafier v1.6b
      XianXi: JNX Raiden, SC Taito Classic, SC Sega System 16/24, Namco System 11/12 KHA
      Frank_fjs: JAMMA Extender (Special HAS Edition)
    • It's 240p120 instead of 240p60, yes it's out of spec, but as long as the emulator can handle this it shouldn't be a real problem. It's like the super resolutions, you can't notice you are on 2560x240 because the emulator multiplies the width by an integer number.

      it's the same effort to maintain correct refresh but double frames for each second, as long as it's integer it shouldn't harm, emulation can handle this because it can send 2 shorter frames from 2 instances of the same game at the same time to fit instead one normal frame, the eye couldn't say the difference, you always see a game that has 30fps content. Real hardware is another problem because it has to create the frame then duplicate it so 1 frame of lag at the minimum...

      I won't be surprised that some day emulation could offert less lag than the real thing.

      I am on the real hardware route if you ask me, I prefer one monitor for each thing, I enjoy more the real experience because it's authentic, and it's probably related to childhood memories, but I always find interesting when emulation don't just mimic but offer new ways to do things.

      Pushing our cheap 31khz monitors to 240p120 is one of the things I find very good when you see the increasing price of trisync solution when it comes to emulation.
      Any Multi MVS bug ? Before asking delete BUFF FILE on the SD card and Reset NVRAM procedure : Power on without cart, Press Start multiple times until it asks to press ABC + Start, Do it, Power off > Done