The Kawai K5 I used to have was also 8096 based.
Intel 8097 in the Roland W30, and I think also the S50.
The later S550 is the unit I was fixing mentioned in another comment, that one was a 8095
Fixing a 30-year-old Roland synthesizer bug
11–20 of 37 posts
Re: Fixing a 30-year-old Roland synthesizer bug
#12Awesome work! I love the care and attention that people put into understanding these devices. I'm currently in the middle of a vintage synthesiser hacking project as well. Last year I made a fully annotated disassembly of the Yamaha DX7 firmware, and did some other technical analysis of the synth. Since then, I've been waiting for a chance to put this knowledge to good use. I found a DX9 on a local trading site, and…
> Last year I made a fully annotated disassembly of the Yamaha DX7 firmware
You beast!
Re: Fixing a 30-year-old Roland synthesizer bug
#13This is cool, so TL;DR: The 3rd gen run of a Roland early digital synth product had an unresolved timing issue causing pitch playback problems. Recently, investigation revealed they hadn’t accounted for an Intel MCU part sub. The spec indicated the sub part was running too fast. They downclocked it via crystal swap which destroyed the unit’s MIDI timing. So they located the control ROM instructions to modify to fix t…
Ah, relief. Big Roland fan but don’t have this particular piece of gear & had trouble following TFA
Re: Fixing a 30-year-old Roland synthesizer bug
#14Awesome work! I love the care and attention that people put into understanding these devices. I'm currently in the middle of a vintage synthesiser hacking project as well. Last year I made a fully annotated disassembly of the Yamaha DX7 firmware, and did some other technical analysis of the synth. Since then, I've been waiting for a chance to put this knowledge to good use. I found a DX9 on a local trading site, and…
I wonder if DX100 firmware could be hacked like that as well, it being another of the 4-op beasts too
Re: Fixing a 30-year-old Roland synthesizer bug
#15This is cool, so TL;DR: The 3rd gen run of a Roland early digital synth product had an unresolved timing issue causing pitch playback problems. Recently, investigation revealed they hadn’t accounted for an Intel MCU part sub. The spec indicated the sub part was running too fast. They downclocked it via crystal swap which destroyed the unit’s MIDI timing. So they located the control ROM instructions to modify to fix t…
Yes, I love that the entire fix is a 5 byte change.
Re: Fixing a 30-year-old Roland synthesizer bug
#16Awesome work! I love the care and attention that people put into understanding these devices. I'm currently in the middle of a vintage synthesiser hacking project as well. Last year I made a fully annotated disassembly of the Yamaha DX7 firmware, and did some other technical analysis of the synth. Since then, I've been waiting for a chance to put this knowledge to good use. I found a DX9 on a local trading site, and…
Are you familiar with Dexed[0]? It’s a free, open source DX7 emulator for most major DAWs. They’ve done similar work in figuring out how the device works internally.
Re: Fixing a 30-year-old Roland synthesizer bug
#17No post body was provided.
Re: Fixing a 30-year-old Roland synthesizer bug
#18This is cool, so TL;DR: The 3rd gen run of a Roland early digital synth product had an unresolved timing issue causing pitch playback problems. Recently, investigation revealed they hadn’t accounted for an Intel MCU part sub. The spec indicated the sub part was running too fast. They downclocked it via crystal swap which destroyed the unit’s MIDI timing. So they located the control ROM instructions to modify to fix t…
It wasn't pitch playback problems it was vibrato rate.
Re: Fixing a 30-year-old Roland synthesizer bug
#19Awesome work! I love the care and attention that people put into understanding these devices. I'm currently in the middle of a vintage synthesiser hacking project as well. Last year I made a fully annotated disassembly of the Yamaha DX7 firmware, and did some other technical analysis of the synth. Since then, I've been waiting for a chance to put this knowledge to good use. I found a DX9 on a local trading site, and…
> Last year I made a fully annotated disassembly of the Yamaha DX7 firmware You beast!
Found it: https://github.com/ajxs/yamaha_dx7_rom_disassembly
It’s extremely documented. More than I was expecting.
Re: Fixing a 30-year-old Roland synthesizer bug
#20This is cool, so TL;DR: The 3rd gen run of a Roland early digital synth product had an unresolved timing issue causing pitch playback problems. Recently, investigation revealed they hadn’t accounted for an Intel MCU part sub. The spec indicated the sub part was running too fast. They downclocked it via crystal swap which destroyed the unit’s MIDI timing. So they located the control ROM instructions to modify to fix t…
It wasn't pitch playback problems it was vibrato rate.
I get what you mean, it was a temporal issue, but it’s a PCM synth. That’s sample playback, and vibrato in that context is a modulation of pitch of sample playback over time. It’s a pitch playback problem that was caused by too fast a clock causing too fast a pitch playback modulation. (The LFO being used to produce the vibrato effect being misclocked due to too-fast MCU, causing a pitch playback problem. The pitch playback modulation was at the wrong rate.)