2x YM2149 from Atari ST on Atari 800XL/65XE/800XE/130XE/XEGS
Looks really cool! I hope they use a through-hole 3.5 mm TRS socket in the final design, though! I think the surface mount ones are prone to breaking...
It will be in cartridge shell. So probably jack will be OK. But it looks very fragile thats true!