If you are interested in using your MiSTer with composite or S-Video output, there are several new options on the market right now. Mike Simone (MikeS) has been developing special versions of each core which can output S-Video natively. Then using a relatively simple adapter, this can be converted into composite. Mike recently finished his design for the dongle and several MiSTer resellers have produced their own versions
Antonio Viliena: https://www.antoniovillena.es/store/product/mikes1-vga-composite-adapter/
While the MiSTer outputs HDMI natively and with an IO board you can output RGB or Component, it is technically much harder than it first seems to get the “lower” quality standards like composite and S-Video.
To use the custom cores from MikeS, you had to build your own adapter or use a few cables in a chain. With wider availability of these inexpensive dongles, you can easily plug this into your MiSTer and get S-Video or composite output straight away. You can use these dongles connected to the IO board or directly to the HDMI output using A DirectVideo HDMI to VGA adapter.
S-Video is easy and can be done with a few cables
The custom core output S-Video natively, which is the Y and C signals directly out of the IO Board (or HDMI to VGA dongle when using DirectVideo. If you only wanted to use S-Video, then all you would need is a cable with a VGA Dsub on one end (to plug into the MiSTer) and a S-Video combing plug on the end. Check out the two video below for more info on this method. Still if you want S-Video and don’t want to f**k around, you can just buy one of the dongles above.
Composite is where you need to pay attention
These cables have extra components called a “luma trap”. These are used for the conversion to composite and the luma trap needs to be refined for either a NTSC or PAL signal. Some sellers have a switch on them (Antonio), while some sellers have optimized for NTSC (MisterAddons). To be clear, the MisterAddons dongle will still work great with S-Video PAL and pretty good for composite PAL, however these circuits were optimized for composite NTSC.
Here are two videos (one from myself and one from the much more handsome Lu) which explain the background to the MikeS cores. Both of these videos were made before the general availability of these dongles. When a reference is made to “making your own adapter” you can now just buy one of the dongles listed above.