The Korg microKEY is a USB/MIDI controller that features 37 velocity-sensing mini keys with a range of four octaves in either direction, up or down, using octave shift buttons. I was interested in this keyboard because I wanted a small portable setup that I could easily take with me to create music and collaborate with friends or just chill out at the coffee table to work out song ideas. The keyboard can be configured to respond to one of eight distinct velocity curves, giving it the feel and response of a much larger keyboard. After getting the microKey home I realized that there was no jack for a sustain pedal. For most piano and keyboard playing a sustain pedal is critical for performance and recording.
Read on to find out how to add a sustain pedal.
The “KORG KONTROL Editor” software allows for customization of the modulation wheel so that it can send midi control change messages. Assigning the hold1 (CC#64) message to the modulation wheel is what enables you to add a sustain pedal. Launch the control software and put 64 in the CC Number box for the Mod Wheel setting. To save the setting to the keyboard, click on ‘Communication” and select “Write Scene Data”.
The next step is to open up the keyboard, void your warranty, and make this product more excellent. Start by turning the keyboard upside down and removing the 8 screws in the recessed holes. The top panel should open easily.
The modulation wheel potentiometer is located on the right side of the open case.
The next thing I did was to measure the resistance values of the mod wheel potentiometer when it is in the down position and when it is in the up position where it triggers the hold1 midi control change message. In the next picture the resistance measured in the down position (A) is 4.67 K Ohms and in the up position (B) is 2.116 K Ohms. To trigger the hold1 midi message we need a way to switch the resistance value to 2.12 K Ohms and that is achieved by leaving the mod wheel in the down position and bridging the bottom two potentiometer pins with a 3.9 K Ohm resistor as shown in (C).
To add the sustain pedal all that is needed is a 1/4-inch mono jack, a 3.9K Ohm resistor (color code – orange,white, red, gold), two pieces of wire and some heat shrink tubing.
Solder the 3.9K resistor directly to one of the terminals on the 1/4-inch jack and then solder a wire to the other end of the resistor. Solder another wire to the other terminal on the jack. cover both of the terminals with heat shrink tubings and then shrink them into place. Note that I used a stereo jack because it’s all I had.
Drill a 1/4-inch hole in the bottom side of the microKey case next to the USB port. Note that there is just enough room for the jack so make sure that you measure the exact spot to drill the hole. Put the jack through the hole and fasten in place with the nut. position the wires so that they stay clear of the square holes in the circuit board. Solder the other ends of the wires to the mod wheel potentiometer terminals with the yellow and green wires attached.
Place the top cover back on and replace the 8 screws. Plug your sustain pedal into the 1/4-inch jack and now you can really enjoy playing the keyboard.
By Karl Williams