Saturday, 26 October 2013

Today's P600fw alpha (october 26)

I took a bit of time to merge changes I made in overcycler back in P600fw, and also added a few missing features.

Here are all the changes I made:

  • Overall speedup: refresh rate at full load is now twice faster.
  • Various fixes, especially in the assigner.
  • MIDI in pitch bend & modulation wheel messages support.
  • MIDI out is now sending note on/off, pitch bend and modulation wheel messages.
  • Footswitch support, can be used to latch new chords in unison mode, and to hold the current arpeggio while arpeggiating.
  • External clock support for the arpeggiator, clock source can be changed using "From tape" + 8 (either MIDI clock, or pulse clock sent into "Cassette in". You can then choose the actual arp clock ratio using the "Arpeggiator speed" parameter, from 1/3 to 1/384).

Also, here's a description of the new user interface commands:

  • In manual mode, or by pressing "To tape" in preset mode, you get access to 20 extended parameters (2 per keypad number), the "Speed" potentiometer edits the last chosen one.

Keypad # Parameter name Choices
First press
0 Arpeggiator speed -
1 LFO shape pulse-triangle,random-sine,noise-saw
2 Vibrato speed -
3 Vibrato amount -
4 Modulation delay -
5 Amplifier envelope shape fast-exp,fast-lin,slow-exp,slow-lin
6 Bender target off,vco,vcf,vca
7 Glide -
8 Unison detune -
9 Amplifier velocity amount -
Second press

0 Arpeggiator speed -
1 LFO osc a/b target ab,a,b
2 LFO speed range low,high
3 Modulation wheel range min,low,high,full
4 Modulation wheel target lfo,vibrato
5 Filter envelope shape fast-exp,fast-lin,slow-exp,slow-lin
6 Bender range 3rd,5th,Octave
7 Assigner priority mode last,low,high
8 Osc pitch mode free,semitone,octave
9 Filter velocity amount -

  • Anytime, by maintaining "From tape" and pressing a keypad number, you get access to misc functions.

Keypad # Function name Choices
1 MIDI receive channel omni,1-16
2 MIDI send channel 1-16
3 Calibrate bender -
4 Select voice 1-6
5 Kill selected voice on,off
6 Dump presets -
7 Set basic saw patch -
8 Set clock source internal,MIDI,tape

Download links at:

A new stable release should be out soon, so please report any problem you could find. Using github issues ( for this would be cool.

EDIT: Built a new version that seems to fix "ghost" tones people had in post-beta1 versions.


  1. Hello, my name is Francesco and I got into your blog while I was looking for some information about midi implementation of the Prophet 600 that I own.
    I saw you made a great job designing a new firmware for this synth. I'm not an electronics expert at all and I'm wondering if is there a procedure to load the firmware straight inside the resident cpu?

    Thank you!


  2. Hi, I also feel, it wakes up my interest for my old P600 very much .. as if it will come closer to the P5 .. or even better. But one question I still have is: Will the chord-memory function still work?
    I will be happy about an answer and will renovate my old one, if that fact will be secured ..
    Carsten Ehlert from

    1. Yes, there is chord memory, it works the same as with the Z80