New Midi Assigner MK2.

The new MK2 model is now a single board allowing for sale as a kit. Plus it includes a second Midi In port and a built in Midi Merger. Current model now has both  two Midi Ins as well as two Midi Outs. Now available as a kit or assembled and tested (new metal box for complete unit will be available soon).

The new kits include everything to build a working unit except the case - the PCB, all electronic parts, LCD, power supply and bolts to attach the LCD. See Kit manual for full information. This kit has two 8 pin SOIC surface mount parts. Soldering instructions in the kit manual.

These Midi Hardware devices are designed to work with older synths to provide midi.patches that create 16 channels of splits and layers across multiple synths.

Designed to plug in after my sequencer, they provide several functions - it lets me play multiple synths at a time while practicing and writing, by letting me use the same input channel multiple times routed to different output channels, or I can define multiple channels, each with the program changes I want to use for a song and not have to set them up over and over again in my sequencer, or any combination of these. A patch defines, for each of 16 input channels - input channel, output channel, key range, bank select and program change. Input and output channels can be used more than once. The Midi Patcher model holds 16 banks of 128 patches. These can be selected by Bank High 0-15 and program change 0-127 from your sequencer on the units settable command channel. So I only add one command into the sequencer and the Patcher switches all of my synths

Since Oberheim synths of the Xpander, Matrix 12, Matrix 6, Matrix 6R  and Matrix 1000 series have both Single patches and Split/Multi patches or banks that can only be selected by sysex, I have added that as well - special ‘Bank’ commands for Oberheim Single, Oberheim Multi and Oberheim 1000. With those selected, you then just select the normal program change.

Although the unit can be fully edited from controls and the LCD screen on the unit, a computer based editor is also provided to make editing patch banks faster and easier. It edits one bank at a time and allows you to send patches and banks back and forth as well as keep backups of any number of banks on your computer. It uses custom sysex to talk to the units, so only a midi connection is needed for any communication with the Patcher. And updates are also sent to the Patcher via sysex, either from the editor or any sysex app, such as C6, that can specify a delay between sysex commands (to give the on board program flash time to write).

It also includes an arpeggiator for your older synths that do not have one. The arpeggiator has its own rate control, or can be driven from external Midi Clock. The arpeggiator has, as well as a Hold mode so it will keep playing after you let go of the keys and a Follow mode. Switch it from Hold to Follow while it is running and any key you press (within the part of the keyboard defined for the arpeggiator) and it will just transpose the entire arpeggio. So one finger key change. The arpeggiator currently supports 32 notes across up to four octaves. The arpeggiator also defines key range so you can use part of the keyboard to run the arpeggiator while the rest of the keyboard can be going to one or more other synths.

After building the first unit for my home setup, I realized that I should add a multi synth voice assigner, to allow me to play two synths as if they were one. For example this lets me play an Oberheim Matrix 6 and 6R as a single 12 voice synth. And it allows me to play the Roland Boutique JP8 and JU6 in pairs as 8 voice synths. The Assigner model is now standard and adds a second synth output on each of the 16 input channels, as well as a selectable second midi out connector that you can route any output to. I use it to connect the second synths of a pair, else I start to run out of channels. The Voice Assign mode works in Dual, Overflow and  Alternate modes  for the number of voices you specify, up to 8 per synth. Separate Bank and Program changes are stored for each of the two output synths on the channel. The Voice Assigner model has extra memory as well as the extra Midi Out port and can hold 14 banks of 128 patches.

This unit supports midi powered midi boxes by Midi Solutions. I have my Assigner unit just plugged between my Roland MC 50 sequencer output and my set of Midi Thru boxes. The Assigner MK2 does require, and comes with, ac power.

Units are housed in our sturdy, hand made .032 aluminum boxes. (Available again soon). These are built by hand to order, so depending on parts on hand, may take up to two weeks to build. Finished in stock items are normally listed on Ebay.

US shipping is included - all 50 states, Puerto Rico, Guam and the US Virgin Islands.

Payment accepted is Paypal.

To get a delivery estimate, shipping outside the US, or for any other questions email  -

Midi Patcher Assigner Kit


Midi Patcher  Assigner Assembled and Tested



Midi Assigner MK2

Midi Patcher (Retired)

Midi Assigner (Old Model)


Assigner Top9
Assigner Back9

Editor Interface


Assigner MK2 Hardware

Onscreen Editor


Windows :

Midi Assigner

Mac :

Latest Firmware sysex file :

Midi Assigner MK2 1.04

Mac Midi Assigner

MidiAssignerMK2 Complete Board 9

Midi Assigner MK2 Assembled and Tested- new cased model coming soon

Midi Patcher  Assigner Complete

(coming Soon)

Kit Manual