Tri-phonic mode (3 note poly).

More Jacks! Some rocker switches replaces with jack socket for more patchability.

The Interval Generator and Patternator pots replaced with precision type.

440Hz tuner tone.

Interval Generator clock input - allows automatic transposition in a variety of ways.

Bar1 / Note0 trigger outputs - versatile alternative ways to trigger the Patternator and Interval Generator

Arpeggiator replaced with mini step sequencer.

Many internal performance tweaks.