Casper Bastl AIKIDO User manual

DYNAMIC
VCA MIXER
AIKIDO

Aikido is a performative quad VCA mixer with flexible submix
routing and two styles of integrated envelope followers. Clever
normalization allows ready-to-go sidechain compression,
expansion, and rapid routing experimentation.
Clickless mute switches and level faders make for immediate
performability, while dedicated attenuverters on each channel
make it a powerful and flexible quad VCA. The main mix output is
accompanied by individual VCA outputs with patch-programmable
cascading mix routing. The Side Chain envelope follower offers
3 different response curves, while the Spectral Follower can be
set to focus on treble, mid or bass frequencies.
In a modular system, Aikido can become your central mixing hub
or a powerful utility. Thanks to the envelope followers, it allows
signals to interact and mix in new ways. Because the VCAs are DC
coupled, Aikido can be used for flexible modulation routing as well.
As a martial art, Aikido teaches you how to harness the power of
your opponent and use it to your advantage. With the help of the
Aikido module, your modular system can become an arena where
anything is possible and small signals get to wrestle over big ones.
The Side Chain envelope follower input is normalized to input
of Channel A, but can be overridden by plugging in any external
signal. Its output is normalized to the CV paths, so you can start
compressing instantly. Patch a kick drum to Channel A and use the
attenuverters to compress (CCW) or expand (CW) other signals.
The switch lets you select the envelope follower response time.
The Spectral Follower listens to the Channel D output (which can
also be your mix output, thanks to the cascade mixing), and you
can select with a switch whether it focuses on high, mid, or low
frequencies. Patch it anywhere to make a spectral compression!
Several Aikido units can be daisy chained to create larger
cascading mixers.
DYNAMIC
VCA MIXER
AIKIDO

4 VCA channels - each has:
clickless mute with light indication
level fader with 6dB boost
CV input with attenuverter
input (DC coupled)
output (DC coupled) cascaded mixing
Mix output (AC coupled)
Side chain envelope follower
input (normalized to A input)
output (normalized to CV inputs)
switch to select response time
Spectral envelope follower
input taken from Channel D output
patchable output
switch to focus the follower to low, mid, or high frequencies
Backside jumpers
select whether direct VCA outputs are pre/post Mute
cascaded mixing input and output (joins 2 Aikidos to
8 channel mixer)
main mix input and output (for chaining the normalized
MIX outputs), compatible with BUDDY
11 hp
PTC fuse and diode protected 10pin power connector
24 mm deep
Current consumption: +12V <120 mA, -12V <120 mA
FEATURES
TECHNICAL
DETAILS

MANUAL
Here is a block diagram of one channel:
And here is a diagram for the whole module:
CHANNEL IN
LEVEL
VCA
MUTE
ATTENUVERTER
CV IN
CHANNEL OUT
PREVIOUS CHANNEL
(IF NOT CONNECTED)
MIX OUT
ALL OTHER
CHANNELS
+
+
PRE/POST
+
+
+-
FAST
MID
SLOW
SIDE
CHAIN
TREB
MID
BASS
SPECTRAL
A IN
LEVEL
VCA
MUTE
ATTENUVERTER
A CV IN
A OUT
ENV OUT
IN
B IN
B OUT
C IN
C OUT D OUT
D IN
D OUT
CASCADED
MIX_IN
IN
PRE/POST
A IN
+
+
+-
B CV IN C CV IN D CV IN
LEVEL
VCA
MUTE
ATTENUVERTER
(IF NOT CONNECTED)
PRE/POST
+
+
+-
(IF NOT CONNECTED) (IF NOT CONNECTED)
(IF NOT CONNECTED)
(IF NOT CONNECTED)
LEVEL
VCA
MUTE
ATTENUVERTER
PRE/POST
+
+
+-
LEVEL
VCA
MUTE
ATTENUVERTER
MIX OUT
SPECTRAL ENV
++
+
++
PRE/POST
+
+
+-
CASCADED
MIX_OUT
OUT

8 7 9
2
1
5
4
6
3
9
1
The VCA signal inputs are DC coupled and accept both audio and
modulation.
2
The direct VCA signal outputs are DC coupled and they mix in
a cascading manner. The output from Channel D will have all the
channels mixed together. Plugging a cable to another output will
break the cascading mixing chain. If you plug all channels A, B, C,
and D, they become independent outputs. Plugging a cable only
to Channel C OUT will have A, B, and C mixed.

3
The offset LEVEL fader opens and closes the VCA. It opens
to unity gain (0dB) at about midpoint and amplifies up to +6dB
when all the way up. The boost is very useful for compression
and feedback. The VCA CV and the offset LEVEL fader combine
to control the channel volume.
4
The clickless MUTE switch mutes (light off) or unmutes (light on)
the corresponding channel. Press and release the switch slowly
to create fade-in and fade-out effects.
The MUTE switch always determines whether the channel is
present in the MIX output. Using the jumper on the back, you can
select whether the direct VCA outputs are affected by the MUTE
switch or not. Set the jumper in the PRE position to have them
NOT affected, or in the POST position to have them affected by
the MUTE switch.
5
The CV input affects the gain between a VCA’s input and output.
CV inputs are linear. The CV signal goes through the attenuverter
and is mixed with the LEVEL fader. The SIDE CHAIN envelope
follower is normalized to the Channel A CV input. The CV input
from Channel A is normalized to Channel B, from Channel B to
Channel C, and from Channel C to Channel D. Therefore, if no
cables are plugged into the CV inputs, all the channels will be
listening to the SIDE CHAIN envelope follower. Plug cables into
the inputs to control the VCAs independently.
6
The attenuverters adjust how much of the signal at the CV input
is applied to the VCA. Set them to the center (there is a notch)
to have no effect. Turn them to the right to gradually increase
how much the CV input affects the level. Turn them to the left to
gradually increase how much the inverted version of the CV input
affects the level. When used with envelope followers, turning to
the left creates a compression effect, while turning to the right
creates an expansion effect.

7
The MIX output has all channels mixed together. It is AC coupled,
which makes it suitable for audio signals, and it removes any
excess DC offset. The state of the MUTE switches is always
reflected in the MIX output.
8
The SIDE CHAIN envelope follower monitors the input level and
reflects the signal volume as a CV value. The Channel A input
is normalized to SIDE CHAIN IN. To use SIDE CHAIN IN
with any other signal, plug a cable into it. The SIDE CHAIN ENV
output is normalized to Channel A CV input, which is normalized
further to channels B, C, and D. This makes the setup ready for
compression.
The SIDE CHAIN switch allows a choice from 3 response
curves, which is useful for 3 different compressor settings. The
FAST setting has a fast attack and a fast release and is suitable
for tight compression. MID is an all-round common setting that
will just work: still a pretty fast attack, but a slower release. The
SLOW setting is useful for more exaggerated side-chain effects
and has a much longer release and attack.
Tip: Send triggers to SIDE CHAIN IN and use the SIDE
CHAIN switch to get different envelopes. Use these envelopes
for compression or use them independently.
INPUT
SIGNAL
ENVELOPE FOLLOWER RESPONSE
SLOW
slower attack
slow release
FAST
fast attack
fast release
MID
fast attack
slower release

9
The SPECTRAL envelope follower has a similar time response
to the MID setting of the SIDE CHAIN follower, but its main
asset is that you can select the frequency band it responds to
with the SPECTRAL switch. The SPECTRAL envelope follower
listens to the Channel D output (cascaded mix output) and has
a dedicated output you can patch anywhere. In the BASS setting,
the SPECTRAL follower responds primarily to frequencies
below 100 Hz; in the TREB setting, it responds to frequencies
above 650 Hz; and in the MID setting, it responds to frequencies
between 100 Hz and 650 Hz.
20Hz 20kHz
100Hz 350Hz 650Hz
FREQUENCY
BASS TREBMID
SPECTRAL ENVELOPE FOLLOWER FOCUS

A
C!
C
B
B
A
PRE/POST jumper
Use this jumper to configure whether the direct output of a channel
is pre or post MUTE switch. If in the PRE position, the channel
output will NOT be affected by the MUTE switch. If in the POST
position, the channel output will be affected by the MUTE switch.
B
MIX IN / MIX OUT
CHAIN HEADERS
Use jumper wires to chain multiple Aikido modules together.
The MIX_OUT headers are doubled so you can connect them
to the left and right chain inputs of BUDDY or to any other two
destinations. If the MIX_OUT jumper pin from the first Aikido
is connected to the MIX_IN pin of the second Aikido, the MIX
output from the second Aikido will have the sum of both modules
unless the MIX output on the first Aikido is plugged in. In that
case, the MIX OUTs on each module will be independent.

C
CASCADED CHAIN
HEADERS
Use jumper wires to chain multiple Aikido modules together. If the
CASCADED OUT jumper pin from the first Aikido is connected to
the CASCADED IN pin of the second Aikido, the channel A output
and following outputs on the second Aikido will have the sum of
both modules unless the channel D OUT on the first Aikido is
connected. In that case, the cascaded mixing of the outputs of
the second Aikido will be independent.
Before connecting the ribbon cable to this module, disconnect
your system from power! Double check polarity of the ribbon cable
and that it is not shifted in any direction. The red cable should
match the -12V rail, both on the module and on the bus board.
! PLEASE MAKE SURE OF THE FOLLOWING
you have a standard pinout eurorack bus board
you have +12V and -12V rails on that bus board
the power rails are not overloaded by current
Although there are protection circuits in this device, we do not take
any responsibility for damage caused by the wrong power supply
connection. After you connected everything, double-checked it
and closed your system, so no power lines can be touched by
hand, turn on your system and test the module.
!POWER!