for my 2 midi accordions Elkavox 83 & Concerto digital accordion :-

2no technics smac 1200 accomps module (each one set up for a different midi accordion )

1no Fantom XR sound module (with 4 expansion boards)

1no Technics KN7000 (with all the expansion boards )

along the way I have owned the yammie Tyros T2 and the Gem XP expander ...neither I'm sorry to say suited me !!(just my opinion )

regards ...Giovanni