With the uniPulse installed you are able to trigger each of the Korg KR-55’s instruments individually via midi. Here we will show you how to add individual outputs that are scaled to line level.
As we look into the schematic of the KR-55 we can see that the volume of each instrument is controlled with a potentiometer. These potentiometes are important because here we can pickup each instrument individually. We do that by installing a voltage divider parallel to the potentiometer. The voltage divider will help us to scale the signal’s amplitude to line level (Peak to Peak ~ 1V) and at the same time the output impedance is reduced.
.Because the instruments have different output amplitudes each one needs an individual voltage divider for scaling:
- Bass Drum
R1=100k R2=10k - Snare Drum
R1=75k R2=16k - Cymbal
here the voltage divider is not needed (R1=0 R2=inf) - Hi-Hat
R1=47k R2=47k - Tom Tom, Conga
R1=82k R2=10k - Rim Shot, Cowbell, Claves
R1=75k R2=16k
Note that for the best result for the cymbal output you have to turn the cymbal potentiometer to the lowes possible volume. Otherwise other instruments are mixed into the output. All other outputs are fine and dont have this “bug”.
We soldered the voltage dividers directly to the potentiometers and placed the 3.5mm jacks at the side of the KR-55’s chassis.
