No shader. That’s just native res on one of my CRTs.
I didn’t mention in the previous post that actual arcade monitors are a pain in the ass to keep up, too. The TV route is probably easier/cheaper, but either way you do it, you need to be careful that you only feed them 15 khz signals because the 31 khz signals that normally come out of a PC can damage some TVs and arcade monitors. Even if you have it start pumping out 15 khz signals as soon as the OS loads, the BIOS signal is going to be 31 khz. This is another convenience of going with a CRT PC monitor.
I have a J-PAC in my cabinet that blocks out 31 khz signals and converts JAMMA inputs to keyboard events. The other option is to use an old video card that has a TV output but, in my experience, you can never actually push out native res through them, it’ll always be your normal PC res (typically at least 800x600) crunched down in hardware to 480i. It still looks good but it’s a little blurry and the interlacing means you pretty much never see the gaps between the scanlines.