Tag Archives: MKS-70

Oberheim Matrix-6R

A couple of weeks ago I scored an Oberheim Matrix-6R on eBay. I’ve had a Matrix 1000 before, but we never became friends. It sounded too much techno and too little vintage. Therefore it might sound strange for me to go and buy a Matrix-6, since their guts are nearly the same. The thing that convinced me was the video review by my favorite Japanese guy, Katsunori UJIIE. He really brings out the nice brass and strings this machine is capable of!

Since I live in Europe and bought it from the US (the rack version is quite hard to find in Sweden, I’ve been looking out for one for a while), I turned to a guy I know to convert it from 110 V to 230 V.  I read on his blog that the built in PSU can be switched by doing something on the inside. I didn’t ask him exactly what, but for someone that’s good with electronics, doing the mod should be piece of cake. I suspect it’s something simple like repositioning a wire and changing the fuse.

When I got it back I plugged it in and was amazed by it’s sound! Fantastic brass presets, perfect for a brass guy like me. Compared to how I remembered the Matrix 1000, this sounded like something completely different. Maybe it’s the combination of more vintage sounding presets and the fact that the DCOs on the Matrix-6 aren’t controlled by the same clock.

Compared to the Roland MKS-70 that took two rack units, and really deserved them, the Matrix-6R definitely deserves its three rack units! I still have a JX-10 that has exactly the same guts as the MKS-70, but honestly, I think I like the Oberheim sound better! The JX-10/MKS-70 with their 24 DCOs are technically more advanced, but they are flirting too much with the digital trend of that time. I also find the Oberheim snappier and the filter more characteristic. To sum it up:

Roland JX-10 / MKS-70
• 24 DCOs
• Roland chorus

• Filter
• Slow envelopes
• Digital sounding presets
• Broken midi/sysex implementation

Oberheim Matrix-6
• Filter
• Envelopes
• Vintage sounding presets

• 12 DCOs
• 3 rack units (compared to MKS-70 2 or Matrix-1000 1)
• Slow CPU, lots of sysex chokes it


Roland MKS-70 arrived

I know it’s a bit insane, but I got a very good deal and bought an MKS-70. The MKS-70 is the rack version of JX-10. The JX-10 contains two JX-8P. So at the moment, I have a total of five JX-8P engines!

It seems to be fully working, has a few scratches on top and the front panel looks very nice. However, when booting it and pressing the VALUE button the screen read “Ver 1.03 FINAL JX”, which is not the last version of the firmware.  Regarding “FINAL JX”, it’s kind of strange because it was not the last JX synth produced (JX-1 was the last one, though it’s not analog)  and it was not the last firmware version either. Just like on the JX-10, the firmware was very buggy on the MKS-70, but they got it all sorted out with version 1.08. I’ll have to open the MKS-70 and check what kind of  EPROM it uses.

Modifiying a Roland M-16C to M-64C and transferring the factory sounds

A couple of months ago I scored three M-16C on German eBay. My intention was to do the famous M-16C to M-64C conversion, since an M-64C costs more than the three M-16C together. Plus it’s good soldering practice.

When I got the JX-10, it had no factory sounds – the internal memory was all messed up. To solve this two things are required:

  1. A Roland M-64C cartridge. The JX-10 can only take full dumps, and those can only be done to a cartridge. Once on the cartridge however, they can be copied to the internal memory.
  2. The firmware upgrade from Colin Fraser. Here’s a post how I replaced mine.

Installing the new firmware is the easiest part. The harder part is to modify an M-16C. So if you choose the easier and more expensive path, just buy an M-64C.


I’ve found two guides the original one and another one based on the original one. The original guide has a nice description, but very low-res photos. The other one has good pictures but a not much text.

The first thing to do is to desolder the old memory chip from the M-16C and for me this was the hardest part. It took about an hour and I used a solder sucker.

Another thing was to actually understand where to solder each lead. Some are easy to see, some are not. One that shouldn’t be missed is the one that you have to solder beneath the chip before soldering the chip.  Here’s a photo from one of the guides, it’s the red lead. It’s connected to the second pin in this photo, very hard to spot, but if you look carefully it’s visible between the blue ones.

You also have to bend a few pins upwards, this is quite clear in the text in the original guide,  in the other guide you can see it in this photo.

The final thing to do is to modify the casing, one of the guides recommends a Dremel, for me a filet knife did the job.


There are some instructions scattered all over the internet,  sosummarized it here:

  1. Download banks and CpJX
  2. Insert an M-64C cartridge
  3. Set the Protect Switch on the JX-10  to OFF
  4. Set the Protect Switch on the M-64C cartridge to OFF
  5. MIDI Channel should be set to 1. [MIDI PARAMETER 12]
  7. Connect both MIDI IN and MIDI OUT
  8. Launch CpJX and configure the right MIDI ports
  9. Load a sysex file and choose Transmit
  10. Go to the JX-10 and push the MIDI button then push the WRITE button. The display responds with: “WRITE MIDI”
  11. Rotate the Alpha-Dial until the display responds with: “MIDI BULK LOAD”
  12. Push the ENTER button
  13. The JX-10 now should handshake with CpJX and the transfer should start. Takes about a minute, and both the JX-10 and CpJX should alert you when the transfer is done.


Upgrading the Roland JX-10 firmware

Some time ago I purchased the JX-10 Sysex Enhanced ROM from Colin Fraser which makes the JX-10 respond to sysex the same way the MKS-70 (the rack version of JX-10) does. It’s only £15 including postage to Europe, so no need to hesitate. Remember to buy it directly from Colin, not from other sellers on eBay. Colin has put a lot of work into this!

Note that you have to have an M64-C cartridge to be able to load the original patches with sysex, the firmware upgrade won’t change that. When the patches are on the memory cartridge they can be copied to the internal memory.

The new EPROM arrived in a static bag attached to an important note informing that inserting the  EPROM the wrong way will damage it. It also had a non-clickable link to the installation instructions.

I did exactly as in the instructions, but with the following three exceptions:

  1. I checked the versions before and after by pressing H while turning on. This was most for fun.
  2. I unscrewed the two screws underneath before the ones on the sides (note: in Colin’s instructions the screws underneath are described as “two larger bolts” – on my JX-10 they were screws).
  3. I did actually not have to loose the flat cable. It was long enough to give the space needed for the ROM swap.