REPLY TO THE ACCORDIONIST:
I am using the KP-200S with a petosa Millenium and a Ketron X4 module. Both the Millenium and the X4 sound great through the amp even at lower volumes. I play mainly for senior citizens in small venues and don't need volume, but do want a crystal clear sound and a good sounding bottom end (with out being loud.)

I use all 8 inputs on the KP-200S: 4 for the X4, 2 for the Millenium module and 2 for a VoicePrism. I use sterio expansion on the X4 channel to simulate the spread of sound you hear from a combo playing. I don't use any expansion on the Millenium/VoicePrism channel because it makes some of the Millenium accordion voices sound like they are synthesized rather than being acoustic. And some of the VoicePrism presets sound strange when sterio expansion is applied. Since both an acoustic accordion and a singer or small vocal group is more of a point source of sound rather than spread out like a combo, not applying sterio expansion is a closer approximation to reality.

Currently when I play with the X4, I don't use the Millenium sounds. I need more time to experiment with layering right hand X4 and Millenium sounds. I am still exploring the sounds on the Millenium and deciding which sounds are best for each song in my book when I play the Millenium only. Going from 11 switches on my Excelsion AC to 12 banks with 12 switches each on the Millenium means there is a lot to decide.

Good Luck!

RJM