CRT_Emudriver csync output clarification

[hector_doepos]

Hey!

I'm planning on building a PC/PVM setup, and I'm just trying to get my head around the way the connection between the PC and the PVM would work.

It is my understanding that with newer crt_emudriver version, you can go directly from the VGA output of a crt_emudriver compatible card, and straight into a CRT via a VGA-> BNC (4 or 5) adapter. However, I can't seem to find much information on this.

This quote from guide to connecting windows PC to monitor is where I got this idea from initially:
https://www.aussiearcade.com/forum/arcade/m-a-m-e-emulation-projects-and-discussion/89704-a-guide-to-connecting-your-windows-pc-to-an-sd-crt-tv-pvm-or-arcade-monitor

IMPORTANT EDIT: Calamity has added full support for composite sync since the Beta 13 version of crt_emudriver! This means your PC can output C-sync directly and you already have RGBS! There will be no need to combine H- and V-sync for yourself. Make sure to read the notes in post #2 of the crt_emudriver download thread before attempting, tough. This means you can ebay a VGA to 4 or 5 BNC cable and just use the connector for horizontal sync to connect to a PVM directly. This probably also means you can use a VGA-to-SCART cable, even if a listing says it's not for PC. However, from beta 12 he has also disabled the flicker filter - see section i) of this guide. I'm hoping to get some information on the level at which sync outputs. Most SCART tv's want a -0.3Vp-p (point three volts peak-to-peak) composite sync signal, but graphics cards delivering H and V-sync do so at 5Vp-p. A PVM or arcade monitor will probably be fine with this, but a SCART TV may not. It's definitely worth a try, however. Make sure to read the notes in post #2 of the crt_emudriver download thread before attempting, though. Note that a BVM or multiformat PVM might not be happy with the C-sync from your GPU, and you might need to try other options below. You can also try the BVM fix in the troubleshooting section, n).

I'd be happy to charge forward with this knowlege, but I seem to see people struggling to get this to work on the forum. I also notice people still recommending the use of products such as the vga to scart  ultimate adapter (http://arcadeforge.net/UMSA/UMSA-Ultimate-SCART-Adapter::57.html) and Extron RGB interfaces.  I am unsure why this is necessary if crt_emudriver can export csync directly from the cards? Or Is it only a subset of compatible crt_emudriver cards that can output Csync directly from radeon/compatible cards? Or is it something to do with that .3+- voltage issue mentioned in the quote?

Sorry feeling a little over my head but would be great to clarify this before purchasing anything. Thanks a lot

EDIT: Sorry i found the post referred to in the quote which clarified this.

http://geedorah.com/eiusdemmodi/forum/viewtopic.php?pid=1009#p1009

[buttersoft]

So... you're all sorted for now?

[hector_doepos]

So... you're all sorted for now?

Hey! Haha. I appreciate you checking in.

So This was the relevant quote in the thread by Calamity I found:

- In order to enable composite sync right from boot, you have to check the corresponding option in ATOM-15 and flash your video card with the modified BIOS. Composite sync will be applied to all available outputs, so that's something you may need to consider depending on your setup.

- Regarding Windows, first of all, an important warning: enabling composite sync may be a tricky business. Even if you know what you're doing chances are you get into a messed video state at some point in the process. Once you get everything right it should work fine forever, you just need to get there. I recommend to always work with two monitors during the process and only enable composite sync on the secondary monitor (the one you're not working with) so in case anything goes wrong you don't get an unusable display. If anything goes wrong and you can't find your way around a messed display, you can boot in safe mode and uninstall the driver.

From this my conclusion is...  That enabling csync direct out of the PC is difficult, and not guaranteed. It doesn't work for everyone and perhaps mixed results depending on what CRT your using. I've also heard that multiformat crts  (I'm using a 14L5) also seem like they might be fussy about the voltage of the csync signal.

I don't fully understand the instructions, but I figure once I get crt_emudriver setup on my arcade machine I'm going to give it a shot. I have also ordered the VGA/SCART adapter so have both bases covered.

Wish me luck!!

Thanks!