AN-4 K1600 MIDI Converter Tips
Some Usage Tips for the K1600 MIDI Converter Module
The K1600 MIDI Converter from Kilpatrick Audio is a small, rather
timid looking Eurorack module that packs a lot of punch. To keep
things slim, only two switches are used to program and configure the
unit, yet its two analog, two gate, four trigger and two clock outputs
can do all sorts of interesting and useful things.
There is a lot of functionally packed into this 12HP Eurorack module
that can offer fun and flexible control of your modular synthesizer from a MIDI
keyboard, computer or other MIDI-capable device. Programmed with only one switch,
the user can select an output or pair of outputs to assign, send a MIDI message and
instantly start using the K1600 with other MIDI gear.
And testing is easy too. Not sure if a connected device is making any sound? Just put
the SETUP / SELECT switch in SETUP mode and the output will pulse (for GATE and TRIGGERs)
or go to a fixed voltage (CVs) for tuning oscillators. With so many functions and possible
ways of using the K1600, we've prepared this App Note to give you some ideas. Of course the
K1600 manual contains all the nitty gritty details if you want specifics.
The Power of Learn Mode
Learn mode is the key to allowing flexible setup without a screen or
buttons. Just select the outputs you care about, and send some sort of
MIDI message and the output learns both the MIDI channel and the type
of message being assigned.
Press a note during learning to make an output respond to a note
message. This works differently for each type of output:
- CV / GATE - The CV output generates a tuning voltage and
the gate output goes on and off when notes are pressed and
released. When in Single or Split-keyboard modes (see below) notes are
automatically assigned based on a Last Note Priority ordering. This
allows monophonic playing that feels quite natural.
- Triggers - Trigger outputs can each be assigned to a note
and used to send short pulses (about 10ms) to drum voices, clock
inputs on other modules and so on. This offers a quick way to connect
a MIDI drum machine or computer to analog drum modules or other
Continuous controller (CC) messages can be easily assigned to both CV /
GATE and TRIGGER outputs. By simply turning a knob or pressing a
footswitch, outputs are assigned to respond to CCs.
- CV / GATE The CV output will send a voltage proportional to
the CC value, and the GATE output will turn on and off depending
whether the same CC is above or below 50%.
- Triggers - A trigger output turns on and off based on whether
the assigned CC level is above or below 50%. This makes it easy to use CCs
to control various modes in your modular setup by enabling and
disabling other modules, using voltage controlled switches, and so on.
Typical K1600 Output Assignment
Pitch Bender as a Controller
Pitch bender messages work quite similar to Continuous Controller
messages, except that their response can be inverted. If you bend up
when learning the output, the response will be normal: gates and
triggers turn on and CV outputs go up when the bender is raised. If
you bend down when learning the output, the response will be
inverted. Gates and triggers will go on and CV outputs will go up when
the bender is lowered. You can assign multiple outputs with different
polarities to make very useful pitch bender-controlled outputs.
Also, gate and trigger outputs are off when the bender is in the
centre position. This means that by assigning a gate or trigger output
to the bender, you can make momentary output pulses by simply moving
the pitch bender in different directions.
Pitch Bender in Note Mode
Of course, when a CV / GATE pair is in note mode, the pitch bender causes
the pitch of the note to change in the normal
way. No separate output is required for the bender, and it has high
resolution so you can make very tiny adjustments.
The bender range can be adjusted from 1 to 12 semitones, which allows
all sorts of interesting effects when playing solos. Just send a
Program Change command from your keyboard to change the bend amount for a CV output.
Split the Keyboard
It's usually annoying to set up split keyboard modes with most synths.
K1600 makes it easy. Just enter Split-keyboard learn mode (CV / GATE
pairs flashing alternately) and then tap a note to select the split point.
The keyboard will be divided and notes will be sent out the CV1 / GATE1 or
CV2 / GATE2 outputs accordingly.
The best part is that each half of the keyboard has complete
monophonic Last Note Priority memory just like in Single mode which work
It's all about Polyphony
One of the most exciting features of the K1600 is the ability to play
with polyphony! Both CV / GATE output pairs can be used together to control
two voices polyphonically. Just enter Polyphonic learn mode (both CV / GATE
pairs flashing in unison) and hit middle-C. Now you can play with up
to two voices with notes being assigned as required. Duo-phonic playing
is easy to set up and fun to use.
Add more K1600s for up to 16 Voices!
But why stop at two voices? The K1600 allows up to 8 modules (16
voices) to be used together. Just send the same MIDI to all modules
(or loop through the included THRU jacks) to make true multi-voice
polyphony possible. Assign each module in sequence by hitting the
white notes starting at middle-C to tell each module which pair of
voices it should be. (C = 1-2, D = 3-4, E = 5-6, etc.) The modules
each assign notes to their outputs when necessary.
To easily tune oscillators when in polyphonic mode, just turn on the SETUP
switches to force CVs to the same voltage. Tune the oscillators to unison.
The gates will pulse allowing you to set envelope generators to the same
response so that notes will sound similar no matter which voice gets assigned
at a particular time.
When connecting MIDI drum machines, or computer sequencers to modular
gear, it's often nice to be able to have analog step sequencers or
other clock-based devices following along with MIDI equipment. The
CLOCK and RESET outputs on the K1600 makes this possible by providing
a very low-latency interface between MIDI and analog clock signals.
The CLOCK output normally sends one pulse per MIDI clock. (there are
24 clock pulses per beat) But that's sometimes not very convenient so
the K1600 can divide the clock from 1 to 48 times to allow devices to
run at other subdivisions of the MIDI clock. Simply send a Program
Change command to any channel to adjust the divisor.
The RESET output pulses when the MIDI stop message is received, allowing
sequencers to be reset automatically.
Direct Control Mode - MIDI to Analog Control
Low-level Control Perfect for MAX/MSP
When designing the K1600, Andrew reserved MIDI channel 16 for debugging
purposes, which he uses when testing K1600 modules. But since so many
modular users are also cool hackers, he published how this works so that
anyone can make use of it. By using Direct Control Mode, each output on
the K1600 can be controlled through pre-defined CC messages on channel 16.
They offer latched or precisely timed output pulses, as well as full
12-bit high resolution control of the CV outputs.
With Direct Control Mode, the K1600 becomes a truly universal MIDI to voltage converter
that can be used for all kinds of things, some of them not even musical! Ever wanted
to convert MIDI to some digital or analog outputs to control a project, turn on some
lights or use for generating accurate voltages for a circuit of your own design?
Andrew does just that with his K1600s! In fact, it's the only production module
he uses in his test rack because it's so useful.
Write a program or make a custom MAX/MSP or Pd patch and start blinking outputs
and making voltages directly from your computer! The best part is that you don't
even need to assign any outputs, because the debug mode always works the same way,
and it can even be used when other stuff is happening.
Typical Direct Control Usage
Hopefully you've learned a few things about the K1600 and some of the advanced features
and interesting possibilities offered by this small, yet powerful module. Send us your
stories or ideas! We love to hear what people are doing with our products!
Questions? Comments? Please email Andrew Kilpatrick at: firstname.lastname@example.org