And I really liked them.
I didn’t really mind the limited polyphony and the small controls because they still felt like the real thing in so many ways. Nevertheless, I thought it might be good to fill in some of the gaps, and thus was born “The Boostique” - a Boutique booster. :-)
The Boostique adds an Arpeggiator based on the Jupiter-8 one (though now much enhanced), keyboard split capability (where the lower part will arpeggiate while the upper part is played directly - optionally output to a different MIDI channel), and provides controls for the built-in delay, chorus and portamento. Because it was easy to add, it also supports recording and looping playback of MIDI note events, and CV/Gate out so I can use it with my Werkstatt and Neutron. (When the arpeggiator is off it just sends the MIDI straight through, so it also works as a MIDI to CV converter.)
I settled on 5 types of Arpeggio:
- Up
- Down
- Up & Down,
- Random (completely random choice of note from the available notes over all octaves)
- Shuffle (play a consistent random rearrangement of the arpeggio)
I also added the following alternatives that can be applied to any active arpeggio mode:
- Repeat every note
- Repeat every 2nd note
- Replay every 2nd note after every 3rd note (making a broken chord pattern)
- Play each note over all its octaves before progressing to the next note
- Ratchet the first or last note in the group (i.e. play it twice at double speed)
- Walk - repeat or reverse the current step with a small probability
- Play the notes together as chords, but at half speed.
- an optional timebase of 2,3 or 4 notes (if set, the number of looped notes is truncated to ensure it is a multiple of the selected timebase),
- an option to arpeggiate the played notes in held order or note order
- a swing option,
- and a latch function to remember played notes.
The only thing left to add is sync over MIDI. Haven’t done that yet because I haven’t needed it yet, but I’ll just copy over the code I wrote for The Euclidean. (There’s clearly some shared heritage for these devices

Here’s a better illustration of the arpeggio capabilities.
It's quite fun to use. My favourite is the Shuffle mode with the Walk variation - it can really generate some interesting melodic patterns.
Ken