The MS6 is a six-voice fully programmable multitimbral analogue synthesizer in a 1U rack box. It utilizes the Curtis CEM3396 sound chips, just as the the Oberheim Matrix-6/6R or Matrix-1000. It can be regarded as a "poor man's Matrix", in that it has the same basic sound quality, but lacks several of the Matrix synthesizers' key features, like Matrix modulation. On the plus side, the MS-6 is fully programmable from the front panel (unlike the Matrix-1000) and six-voice multitimbral (the Matrix-1000 is monotimbral, and the 6/6R bitimbral).
The MS6 was built by a British company called Cheetah, who started out making low-cost home computer accessories, and moved on to making musical products. Most well known are perhaps the master keyboards. Also well known unfortunately the low production quality, which also affected the MS6.
In a few words: the MS6 is basically the only multimbral compact affordable analog rack synth I know. More specifically:
What's not so nice is:
Being interested in analog synthesizers, but still a programmer at heart I decided to do a slight rewrite of the operating system. I won't go in to all the gory details here; suffice to say that the program code is quite easy to read; probably not written by an ace programmer, but at least it gets the job done. It also is quite easy to modify.
Finally, I came up with the following changes:
The extra patch locations were acheived by packing the patch data in the internal RAM. The sysex dump format is basically the same however. In order to maintain compatibility with the stock MS6, the dump of the first 96 patches is the way it always was, with the final 32 patches being sent as a separate dump immediately after the first 96.
The final result is available as a file ready for programming into an EPROM, to replace the factory ROM in the MS6. Email me if you want a copy of the file!
Well, I haven't planned on putting anything up here yet, but I did add a rotary volume control, which is a godsend. (You can see the new volume pot at the bottom right of the picture above.) Also, the machine I have suffers from improper grounding; basically, the PCB is not connected to the case at all. An extra wire cured this.
If you find an MS6 you may well find it needs a few hardware mods...just to get it working! As I mentioned before, quality in Cheetah products is somewhat of a dubious issue; mine has always performed flawlessly but it appears to have been rebuilt at the factory. From what I can tell, the front panel board and main board were supposed to be connected by a couple of flat cables which plugged into connectors on the respective boards. On my machine, the wires have been soldered into place, which takes care of any dodgy connectors.
Apart from that there are a number of mods I could think of...
Yeah, there are a few that would be nice. Although the MS6 supports sysex dumps, individual parameters cannot be edited via sysex, which is a pity. Also, it would be nice to be able to edit individual parts of a multitimbral patch without having to exit into monotimbral mode. I don't think I'll ever get around to doing anything of this however.
Got any schematics for the MS6? Because I sure don't! From time to time people have asked me if I have any schematics for the MS6, and I've taken every oppertunity to ask other .net people. Unfortunately, the schematics seem nowhere to be found. It could be they were never released, or that Cheetah folded before a decent service manual could be produced. If you dohave a copy of the schematics, I'd like to know about it!
However, the service manual for the Oberheim Matrix-6/6R can be of a certain value as it uses the same sound chips. Most of the circuitry around the CEM3396's are based on the CEM3396 application notes anyway. At any rate, when it comes to the CEM3396 circuitry, including the output stage and noise generator, and largely the timer chips for the DCO timing, a great deal of help can be had from the Oberheim schematics. The rest of the circuitry is most likely a run-of-the-mill 8-bit microcomputer (but using a 6303 microcontroller instead of the 6809 CPU used in the Oberheim), but without any proper schematics, any quirks in the circuit are hard to guess...
Well, there aren't to many of these. An excellent one is Kristofer Maads MS6 resource center, including a text version of the manual, a patch editor, disassembly of the ROM code and more! Kristofer is also planning to do some serious ROM hacking adding some interesting new features!
Back to my analog home page.