Boosting my Boutiques

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!
Post Reply
Common Wiggler
Posts: 118
Joined: Sat Jun 29, 2019 7:26 pm
Location: Sydney

Boosting my Boutiques

Post by kallikak »

When I was in school learning to use a System 100, I viewed the Jupiter-8 and Juno-106 as kind of unreachable, wondersynths! Very occasionally I got to see one, but never really got to use one. So when I got back into synthesis and learned about the JP-08 and a JU-06 I jumped at the chance to fulfil a bit of a childhood dream. :-)

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)
over a selectable range of 1 to 4 octaves.

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.
Other options include:
  • 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.
Finally, the limited polyphony did begin to bother me, so I added a second pair of MIDI connections, and if “Chain” mode is selected, I use sysex to keep the control settings for two Boutiques in sync (I sold my JP-08 and bought a JU-06a which is close enough to the JU-06 to chain effectively) and pass the notes out in round-robin fashion (thus avoiding the chaining bug in the native Roland chaining implementation).

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 :hihi: )

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.

Post Reply

Return to “Music Tech DIY”