The Evolvers, and presumably the P08 too (though that's a guess), do not necessarily need the keys holding continuously to play a sequence. I just checked the manual for the P08, and it is, indeed, a "gated sequencer" : "That is, a note must be played, either from the keyboard or via MIDI, in order...

Hey All, I've used a bunch of analog synths but have yet to come across one with an arpeggiator that I like as much as, yes, the microkorg. WTF? I love the trigger setting where you can play a chord and the arpeggiator will comp it with the step-sequenced pattern. And then with key-sync off you can ...