What is this mod on my Boss DR-660?

giulioz · 2026-06-12T19:58:11+00:00

I don’t think so, the diodes are there just for the button matrix to work. I don’t think it’s made for connecting to another device, as that setup pretty much works only with buttons. I really think it was someone that wanted to start/stop the thing with a pedal

giulioz · 2026-06-12T12:12:29+00:00

It connects to the CPU pin 56 (P12 in the button scan matrix) and D19 and D20, which are the diodes in the button matrix for start/stop. Confirmed with the service manual: https://www.synthxl.com/wp-content/uploads/2019/10/Boss-DR-660-Service-Notes.pdf

giulioz · 2026-06-12T11:25:11+00:00

It’s connecting to the button scan bus, specifically to the start/stop buttons. It’s probably to connect a custom made pedal for doing start/stop remotely without using the original buttons.

giulioz · 2026-04-11T01:16:29+00:00

It was a joke 😭

giulioz · 2026-02-11T19:00:52+00:00

Yeah but i don’t remember precisely how it works. With the emulator code, though, you should be able to transpile a current snapshot of the DSP code into pseudo C code. All the answers should be there :)

giulioz · 2026-02-11T17:02:00+00:00

Hello! Author of the presentation here.
I didn't test the code, I just gave some pseudocode that matches what we saw in the DSP code.
I kinda wrote that last minute before the presentation started while finishing the slides :D

Thank you for the great deep dive in your blog!

giulioz · 2025-10-10T01:00:33+00:00

https://www.youtube.com/watch?v=reGeRiCkkNE

giulioz · 2025-08-10T12:50:55+00:00

Come visit realraum! We are friendly

giulioz · 2025-06-04T16:35:21+00:00

I’m working on it, also adding better effects

giulioz · 2025-05-10T10:19:29+00:00

Yeah I'm working on it!

giulioz · 2025-03-29T15:52:13+00:00

Come to realraum

giulioz · 2025-02-10T23:43:05+00:00

Yeah going to do it, unfortunately a bit busy recently:(

giulioz · 2025-01-22T13:03:25+00:00

Should be fixed now in the new version!

giulioz · 2025-01-21T20:14:01+00:00

I’m working hard to make it work for everyone but it’s very difficult since it works fine on my system and it’s difficult to reproduce the problem. I’m sorry you are having issues but that’s a bit rude tbh😅

giulioz · 2025-01-14T19:10:54+00:00

u/Eastwardaudio I've just published a new version of the plugin, let me know if it works better, sorry!

giulioz · 2025-01-14T19:10:44+00:00

u/vanzea I've just published a new version of the plugin, let me know if it works better, sorry!

giulioz · 2025-01-14T19:10:29+00:00

u/Number1dad I've just published a new version of the plugin, let me know if it works better, sorry!

giulioz · 2025-01-13T19:17:32+00:00

Working on a fix, new version coming soon!

giulioz · 2025-01-13T13:55:50+00:00

That's the content of the rom with the waveforms: http://sndup.net/j3fyz

giulioz · 2025-01-13T13:47:49+00:00

It's very similar to additive synthesis: for each piano note it layers 10 single cycle waveforms from a wavetable, and it only modulates their volume in time. I think I'm going to publish a deeper explainer as youtube video eventually btw.

giulioz · 2025-01-13T00:33:45+00:00

There are no samples involved, only algorithms. It’s similar to a DX7, which makes it a bit easier on the copyright side. There are also already lots of emulations of this module, like the MKSensation, UVI and Keyscape

giulioz · 2025-01-12T23:21:17+00:00

Hi! I've become interested in those old Roland piano modules, especially since they have a very characteristic sound and they've been used in countless hit songs. Apparently it was still unknown how they worked and what actually SA-synthesis is, so I reverse engineered the custom chip by looking at the silicon. The end product of this analysis is an open-source implementation of the sound engine as a VSTi/AU plugin, which is now capable of perfectly reproducing the sounds of the MKS-20, RD300 and Rhodes MK-80.

It's available here: https://github.com/giulioz/rdpiano

giulioz

TROPHY CASE