Fed up with the noisy and low quality sound output via the standard AV out, I decided to install a digital audio breakout board into my Super Famicom. It wasn’t a particuarly tricky install – cut out a suitable hole for the port at the back of the console and wire up 7 wires – but the solder points were quite small, and would be a challenge for first timers.
The board takes the pure audio signal directly from the SPC sound chip of the console and outputs it via lossless optical audio. Works flawlessly on my setup, and the difference in quality is outstanding. Some examples I recorded can be found here: https://soundcloud.com/richisclearlyawesome/sets/recorded-from-my-snes-with-the-digital-optical-out-audio-mod
Pretty confident that my RGB modded Super Famicom Jr with this mod is now the best SNES you can possibly get.