Synth-diy-test

No this is not how Roland's SH-09 synth was meant to sound...

My SH-09 had various bits missing when I was given it. There's more info 
here:

http://synth-diy.org/pipermail/synth-diy/2025-September/175724.html

I just made a little PCB to replace the unobtainable sub-oscillator 
divider chips that were originally missing. And thanks to Don's analysis 
of the DN819 datasheet, the new dividers now clock off the "fixed" edge 
of the VCO pulse waveform. The sub now sounds rock steady like it does 
on a Juno or a SH-101.

My PCB just has the same circuitry that an SH-101 has for the sub. But 
35 years ago, when I originally attempted to fix it, I didnt have access 
to the Internet for service notes or even know that the SH-101 existed 
and worked similar inside.

To be honest when I got the SH-09 working as a young lad I was blown 
away... It was the first "keyboard" I heard that made sounds like the 
music I was listening to in my youth.  Been hooked ever since!

-Richie,


On 2026-02-04 23:24, Adam (synthDIY) wrote:
> 
> Richie is this how all SH-09s behave, or was there a fault?
> I can't recall mine warbling but because it's a sub, maybe I didn't 
> notice...
> A
>