Kawai R100 QuadROM (x4) Board

It’s important to have a bunch of unfinished projects on the go 😉 so here is one more on my list. If you recall, I sell a PCB for the Kawaii R100 that has three EPROMs on it. This gives the R100 user access to all 3 Kawai factory sound ROMs. And the ROMs in question are pretty large (40 pins). Each sound ROM contains a full set of 24 instruments.  I call this the standard 3x board and you can see it on a previous post here: http://musictechnologiesgroup.com/blog/wp-content/uploads/2013/08/P1030676.jpg

And now, the new 4x:

Kawai R100 QuadROM board

4x sound ROM memory expansion

I recently started playing with even bigger EPROMs (42 pins). This means I can put all 3 factory sound ROMs in one chip and still have a bank left over for more custom sounds.  This board I’m calling the “QuadROM” 4x board. See above. It can hold 4 sets of 24 instruments in the one chip. Less soldering for me.

P1040416 P1040417 Of course in both cases the user can make their own EPROMs using my R100 Builder software, but for the 4x it means you need a pretty decent programmer since the cheapie programmers may not do the 42 pin EPROM; at least not without an adapter.

Also, because there are now 4 banks, it means a simple 3-position toggle switch won’t do. I have to invest in a quality 4-position rotary switch that is still small enough to fit in the R100.  Anyway fun stuff on a Saturday. I will work on it more as time allows and see what comes of it.

Posted in Kawai R100 | Tagged , , , , | 5 Comments

Yamaha DX7 ROM Cartridge BINs

DX7 ROM 3 Cartridge EPROM

Yamaha DX7 Cartridge guts

I needed to get the BIN data from some DX7 cartridges, but I don’t have them all. I only have ROM3. So I desoldered the EPROM in the ROM 3 and compared that to the .SYX files found easily on the web. So then I threw together a quick application where I could take DX7 bulk voice dumps and create an EPROM from that.

Note that the Bank B data actually appears in the ROM space before the Bank A data. That’s just because of the decoding on the Bank A/B switch.

MTG DX7 Builder

Make a ROM cartridge from Sys Ex data

As I mentioned in the SuperMAX Redux post I also have the BIN data for the E! presets (256 of them are stored in half of the 27512) as well as the SuperMAX ones (64 of them in half of one of the 27128’s). So it would be possible to replace the data in those EPROMs if one wanted different presets in either of those expansion boards.  Anyway that was my weekend.

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Yamaha DX7 SuperMAX Redux

Something else I’m working on…

SuperMAX plus LCD screen

SuperMAX+ LCD welcome greeting

The new circuit boards just arrived and the testing so far is good. The boards are a slight improvement over the original: I’ve increased the size to allow for a screw to hold the board down and I’ve added a battery holder (not installed) for folks that might want to make a better setup for the CR2032 RAM backup battery.

Yamaha DX7 SuperMAX+ PCB

Posted in Yamaha DX7 | 13 Comments

Vintage Synth CPU Updates, Upgrades and Expansions

There are so many CPU upgrades now for our beloved synths of old, that I thought it would be nice to have a catalog of them all in one place. If someone else has done this already, please let me know. Here are a few I can think of. Add new ones below and I will incorporate them into the master list here.

  1. Korg DW8000: Turbo-DW … http://www.musitronics.org/products/dw8000_ex_e.html
  2. Korg Mono/Poly: Midipoly … http://midipolis.blogspot.com/p/midipoly-manual1.html
  3. Korg Poly 6: Kiwisix … http://kiwitechnics.com/kiwisix.htm
  4. Korg Poly 800: HAWK-800 … http://patrioticduo.tripod.com/hawk800/index.html
  5. Rhodes Chroma: The Chroma CPU Plus (CC+) … http://www.rhodeschroma.com/?id=cpuplus
  6. Roland Juno 6: Tubbutec Juno-66 … http://tubbutec.de/juno-66/
  7. Roland Juno 60: Tubbutec Juno-66 … http://tubbutec.de/juno-66/
  8. Roland Juno 60: Minerva… http://midipolis.blogspot.com/p/minerva-manual.html
  9. Roland Juno 106: Kiwi-106 … http://kiwitechnics.com/kiwi-106.htm
  10. Roland Jupiter 4: Io … http://midipolis.blogspot.com/p/manuals.html
  11. Roland Jupiter 6: Europa … http://www.synthcom.com/Europa/productEuropa.html
  12. Roland JX3P: Inque Organix MIDI Expansion Kit … (used market only)
  13. Roland JX3P: Kiwi-3P … http://kiwitechnics.com/jx3pupgrade.htm
  14. Roland JX10: Vecoven Super JX … http://www.vecoven.com/superjx/superjx.html
  15. SCI P600: Teensy P600fw … http://gligli.github.io/p600fw/
  16. SCI Pro One: MTG TurboCPU … http://musictechnologiesgroup.com
  17. SCI Pro One: Per Linné UC-1 … (used market only)
  18. Yamaha DX7: Special Edition EPROM … (eBay and other places)
  19. Yamaha DX7: GreyMatter E! … (used market only)
  20. Yamaha DX7: SuperMAX … http://www.musictechnologiesgroup.com/lcd_upgrades.htm#supermax
  21. Yamaha DX7 4x EXP … http://www.musictechnologiesgroup.com/lcd_upgrades.htm#dx7_4x_exp

And if I get the dashes wrong in the synth name, let me know.

Posted in Pro One CPU, Uncategorized, Yamaha DX7 | 4 Comments

TurboCPU v1.40 (beta) is available

A new version of the TurboCPU+MIDI firmware has been uploaded to the website, along with a new version of the Windows application TurboCPU.exe.

Added: “MIDI Note Priority” which supports 4 modes: Lowest Note, Highest Note, Last Note and my original mode (called One Note). There is a 10 note stack for Lowest, Highest and Last (the default is Last). The Last, High and Low Note priorities read the RETRIG switch live to determine whether a new envelope is triggered on subsequent MIDI keys down or not.



Posted in Pro One CPU | 1 Comment

MIDI Patch Change Editor v3.31

Ok folks, I have uploaded v3.31 of the PC editor for the MIDI Patch Changer. There are several bugfixes regarding Preset Navigation and the MIDI Events Editor. As well, by popular demand, a “Cancel” button has been added to the Midi Events Editor so that you can abandon your changes. Sorry that took so long. The web page and manual need updating a little, but the latest stuff is online at:

Posted in MIDI Patch Changer | 2 Comments

MIDI Patch Changer: Set Patch Range Hack

Here is a relatively easy hack to let you change how the MPC keypad display MIDI Program Change numbers: as 1-to-128 or 0-to-127. This setting is made available as kind of a “hidden” feature. Hidden in the sense that you have to send a System Exclusive (Sys Ex) command to the keypad to turn it on and off.

Send any MIDI data

MIDI Program Changer/Controller

First of all, here is the manual description for the feature:

Set Patch Range

You can set the range for the Patch Change values to be 1-128 or 0-127.  Underneath, the firmware always transmits the hex values according to the MIDI Spec. (0x00 to 0x7F hex which is 0 to 127 decimal), but most MIDI gear uses 1 to 128 for patches.

NOTE: The editor/librarian only supports program change numbers 1 to 128.

You can send either one of these Sys Ex commands at any time. You don’t need to put the keypad in any special mode. To send a command you will need a utility program such as MIDIOX or SendsSX, or perhaps you can a way of sending Sys Ex from a Sequencer PC application.  Here are the commands:

  • F0 7D 22 22 09 00 00 F7
  • F0 7D 22 22 09 00 01 F7

The first is for range 0 to 127 and the second is for range 1 to 128.


Posted in MIDI Patch Changer | 1 Comment

A Plethora of DX7 Backlit LCDs

I had a chance to grab a bunch of LCD’s for the original Yamaha DX7 and picked up a variety of colors.  They are all really nice and look much better than my photography suggests.

LCD_BlackOnBlue LCD_BlackOnGreen LCD_BlackOnWhite LCD_GreenOnBlack LCD_GreenOnGreen LCD_WhiteOnBlue

Posted in Yamaha DX7 | 2 Comments

TurboCPU DAC/CV Option – New Parts Source?

I made an interesting discovery on the web today. There are a lot of companies making “Breakout Boards” and “SMT to DIP Adapters” but I’ve never found an assembled one for the MCP4728 DAC used in the TurboCPU’s CV/DAC option … until today!

From here:  http://www.proto-advantage.com

I just ordered one assembled breakout board (DAC chip and pins installed) as well as just a blank board with machine pins. I will test them both out. If it all works out then this is a good place to order these parts from because making the CV Option is a major bottleneck for me.

Here are the parts I ordered:


MCP4728 Breakout Board, chip included, assembled.


Part Number: PA0027-MCP4728, MCP4728 Breakout Board

MCP4728 DAC breakout board, unassembled, DAC not included.

MCP4728 DAC breakout board, unassembled, DAC not included.


Part Number: PA0027, unassembled with machine pins, ROUND.

A few things to note about this right up front. Since the beginning of 2014 I have added a second area on the TurboCPU’s MIDI board to put the DAC chip on. The original area is the tiny MSOP-10 footprint, the new area is a 10-pin DIP footprint.

MIDI board showing both DAC locations (in red)

This has allowed me to order MSOP-10 to DIP adapter boards… which makes assembly a bit easier.  To date I’ve been using adapters from




but this new discovery from Proto-Advantage is very exciting! Now, because I’ve also been installing a 10-pin DIP socket I think the round machine pins are the better way to go as I’ve never really liked the idea of jamming square wire-wrap pins into a DIP socket.

The other alternative is for me to leave off the DIP socket and just allow you to solder the Proto-Advantage fully assembled breakout board right on the PCB. Once I get these and test them out I’ll decide which route to go.

Posted in Pro One CPU | 2 Comments

Time for Kidney Transplant

Hey kids,

I’m getting a new kidney.  Wish me luck!  Soldering and programming to resume as soon as I’m able, but I imagine that’s at least a few months away.


Posted in Kidney Transplant | 3 Comments