Roland Compu Music CMU-800R

[DrBunsen]

[img width=300 height=200]http://www.synthdiy.com/files/2001/cmu800.jpg

The Roland CMU-800R is an analog synthesis add-on system for early 8-bit computers such as the Apple II or Commodore 64.  The analog hardware provides four bass/melody voices which are said to be similar to Roland's SH-101 or TB-303 circuits, and a drum set similar to the TR-606, although with very limited/no editability as-is.  In addition there are 8 CV/gate outs, a clock in and out (which I assume is 16th note triggered) and four volume faders.

Sequencing and some voice editing is provided by software running on the host computer.  A computer-specific add-on card connects to the CMU via a ribbon cable.  Neither the card nor the software is available and no-one seems to have them.  I've looked  ::)

The plan is to bypass the onboard CPU and replace its signals with a MIDIbox Core and custom/adapted firmware, possibly based on the MBCV, SID and/or FM.  This seems simpler than trying to reverse engineer the protocols to write to the machine via the ribbon cable, and should allow much more extensive modification into the future using MIOS.  For example, MIOS control of mods and bends to allow more tonal variation, LFOs, ADSRs, groovebox SEQ  ;D

I've attached the schematic below.  When I've fully dismantled the unit, I'll add scans of the two PCBs - a lower PCB hosts the CPU and I/O, and an upper one the analog voices and front panel hardware.

[DrBunsen]

Here's the complete system on youtube:

[maniac]

Hi,

no need to reverse enginering - You can find simple solution on this site:  <http://homepage2.nifty.com/rjb/cmu800.htm>

Best Regards,

Przemek

[Ashiman]

http://homepage2.nifty.com/rjb/cmu800demo.mp3

brilliant ^^

[nILS]

That reminds me of an old ROLAND sound canvas I once had =)

[Jaicen]

Dude, did you get this off ebay last week?? I was going to bid on it, but I was at work :(

Still, glad it went to somebody that appreciates them.

Are you planning to mod the analogue circuits to get more control?? That MIDI retrofit looks pretty tasty, even though I can't read the text!

[stryd_one]

Yeh he did, there was a line of midiboxers behind him it seems :D

[Ashiman]

i was starring on a pair of these once for 4 day, only to discover it was listed at matrixsynth, fuck that blog i tought  :P

[DrBunsen]

Hi, no need to reverse enginering - You can find simple solution on this site:  <http://homepage2.nifty.com/rjb/cmu800.htm>

Thanks maniac, but all I can see on that page is ????????????????????????????????.  I see you're Polish - is it a Polish page?

The little text I can make out says it's a PIC based project anyway.  I'd rather MIDIbox it so I can

mod the analogue circuits to get more control

;D

Dude, did you get this off ebay last week??

You mean this one?.  Yeah.

[bill]

I had one like this in my hands, (a friend gived it to me) but i never found any info on this (like where to get softwares to control it etc)

so i trashed it  :'(

Stupid me, i could'nt imagine it sounded that good !

[DrBunsen]

TO DO list:

• Dismantle and scan PCBs
  
• Print out them and schematics
  
• Document CPU pin function
  
• MIDIO128
  
• Have fun
  
• Examine analog circuits for mods
  
• ....
  

[Jaicen]

TO DO list:

1.  Write TO DO list.

LoL!

Actually that's not the one I was looking at, that was in the UK. Pretty much the same though.

I'd be interested to see what you can do with that thing.

[maniac]

Thanks maniac, but all I can see on that page is ????????????????????????????????.  I see you're Polish - is it a Polish page?

No, this page is in japanese... You may translate it to english using http://translate.google.com/translate_t?langpair=ja|en.

BTW. I'm also trying to get one of this beauties on ebay… :)

[DrBunsen]

Sorry, the computer I was using yesterday clearly didn't have the Asian fonts installed.  All I could see was ?? ?? ? ?? ?? ?? ? ?? ? ? ?.  And I cut and pasted it  ::)  Of course, I can see now that it's not Polish

Don't hold your breath for updates on this.  There's a couple of million other things I have to do before I get stuck in to it.

It occurs to me that the first thing to try and achieve is probably to get the CV/gates working.

Meanwhile, I'll machine translate that website and see what I can dig out.

[DrBunsen]

Two.  Wires.

My bad.  THIS pic seems to show how it connects to the motherboard:

Presumably the pins at the rear go into holes in the CMU's PCB.

And the assembly code is there, which is nice, even if it is annotated in Japanese  ??? Should be able to work out from that which pins to bang and when.

[TheAncientOne]

http://homepage2.nifty.com/rjb/cmu800demo.mp3

brilliant ^^

yeah! kind of like silent move meets video game.

[inteliko]

I got one NIB about a year ago, w/ the software, just need an Apple IIe to copy it and I'll hook yall up, and yes I prefer to Midify it. Matrixsynth posted that jap link a while back also, I wouldnt even have the slightest clue on how to start, I'm just barely understanding on building the MB-Seq. I think I contacted Radio Junk box correctly but he probably just got an email that said ? ?

[inteliko]

Update, I just checked Rjb's blog and he has posted an update to this, I can barely understand the google jap to eng translation though. ASays there is some kind of re-shuffling problem

http://www.google.com/translate?u=http%3A%2F%2Fwww.rjblog.net%2F&langpair=ja%7Cen&hl=en&ie=UTF8

[inteliko]

Found this link off Rjb's site also, 303/909 clones

http://64.233.179.104/translate_c?hl=en&langpair=ja%7Cen&u=http://analogclone.com/

[Ashiman]

that 909 is superbad .. i can barely understand why no pcb distribution  :P

[Ashiman]

??????????????????? Internal squeezing and stuffing is quite a mad woman.

The PCB is so messy. The PCB is so messy. LOL

[inteliko]

??????????????????? Internal squeezing and stuffing is quite a mad woman.

The PCB is so messy. The PCB is so messy. LOL

I guess mad woman means bitch??

[Ashiman]

ask him that we want to mess with the pcb and correct the errors. Also we want to swap the eprom and upload samples  (someone did that for the Jomox gear) and play back via basic 14 bit r2r dac. We also want voltage control : DD

[inteliko]

Even with the midi mod it sends cv-gate out and has 8 ch of it, if possible to upload samples why not, but they wouldn't be too editable i bet. Contacting this guy is hard, there is  a contact link on one of his pages that is all Japanese, not easy searching for it through Google translate. I used that contact page about a week ago with no reply but mysteroiusly on google translate his blog does show some updates, anyone speak/ write good japanese??

[Ashiman]

Look for SounDuke on chattage. BTW i tought of da 909 , maybe with some SOIC uC covert operation ;)