MSX Tribute DIY sequencer


Hello there !

I’m working on a diy synth/sequencer for a while now, but i felt that it had to be quite advanced before i can start speaking about it, maybe because i’m a bit shy, maybe because i lack confidence, i don’t know.

I felt that because Olivier work inspired me a lot i had to open a topic here to speak about it.

So here’s the concept :
The “MSX tribute” is a step sequencer based on real hardware chiptune OPLL that was the first fm chip used in MSX cartridge, was the sound chip in the last Sega Master System available in Japan, and appeared also in some Yamaha synth from the porta serie back in the late 80s/90s.
The chip features 9 instrument voices or 6 voices + a drum kit (Hihat, Cymbal, Tom, Snare, Kick).
It has some hardware limitations, such as rom stored instruments and drum sounds, and a 2 operators FM synthesis is available but shared between voices.

Here’s the synth prototype at the moment :

and some sound demos are available here (sorry for the bad quality, i’ll record things in a better way soon):
drive demos
Link to video

And here are the features :

  • 11 tracks (6 voices, 5 drum kit)

  • 64 steps/track

  • steps parameters :

Gate Length

  • tracks parameters :

Volume ()
Octave shift (
Note Shift ()
Instrument (
Time Scale (from 1/1 to 1/32)
Reset Step (track length)
Gate Length shift (*)

  • full access to fm parameters of the chip, 24 in total.

At the moment, i added 3 LFOs, and i’m still working on a solid modulation matrix.
All the FM parameters and the one with an (*) are assignable mod targets.
Every parameter can be stored on an SD card at the moment, and patterns can be changed in live.
Clock can be internal (from 60 to 240BPM, with a resolution of 96ppqn) or sync by midi in.

I’m still working on some developpment at the moment, but i feel that i’m close to something i start to be proud about…
Could someone here tell me about what he thinks about this ?

Thanks in advance


sounds really fuzzed out and cool!

is the idea you’d do all programming on the device, or does it accept midi to be controlled by something else as well?


Do you mean midi CC for parameters control ?

If it’s your point, that’s in my todo list :slight_smile:


looks amazing and the demos sound great. Looking forward to your progress!


Thanks :slight_smile:

I’ve just added a video on Youtube of me playing it for 15minutes. Not the best quality of video and sound, i should make a better one soon.
Still a good proof of concept !
Link to video


Wow it seems pretty far along! Looking great so far.


Thanks a lot!
I try to go on the development, but as I told, I waited for something advanced enough to start speaking about it.


Some news !

First, i openned a soundcloud where i’ve uploaded some new sounds.
Here it is : SoundCloud

I’ve received new PCBs for the soundcard, which improved a lot the sound quality, i think, and i changed how i recorded things.
I’ve added a second chip to mirror sound, or add some other features.
And eventually, i’ve taken time to lasercut a beginning of a case :

Cheers :smiley: