Koma elektronik SVF 201 User Manual

SVF 201

Front Panel Connections & Controls

ANALOG STATE VARIABLE
FILTER
_

USER MANUAL

Dear KOMA user,

Thanks for purchasing one of our Eurorack modules: the
SVF-201 Analogue Vactrol State Variable Filter! We are very
happy you decided to add a nice shade of white (with a back­lit knob) to your Eurorack Modular system!

We tried to make this module just as versatile as our other
products and are confident we succeeded in that! Before
you get started, please let us introduce ourselves to you…

We are KOMA Elektronik, we come from Berlin, a town filled
with musicians, producers, artists and remixers. Music is
everywhere. We make music ourselves as well, sometimes
successful, sometimes less successful, but we have a good
time doing so. And that for us is what it’s all about: the
fun of creating sounds nobody else made before; the fun of
crossing all borders and let your imagination go, the fun of
exploring musical boundaries and not looking back!

Our filter resembles that vision: compact, yet powerful, the
SVF-201 is a state variable filter for the Eurorack modular
synthesizer system. Its circuit is built up with optical parts
(vactrols) delivering excellent studio audio quality and an
unique warm analogue sound.

The module uses parallel mounted PCBs so it can be used
in skiffs as well as in big cases, the total depth is less
than 4 cm. The SVF-201 comprises 4 audio outputs that
can be used independent of each other at the same time,
a High Pass, Band Pass, Low Pass and the unique first ever
CV’able Mix Out, which allows you to sweep continuously
through the other three outputs by means of a knob and
control voltage. Now wire up that filter and get funky!

mere

Cutoff 1

Sets the cutoff frequency for the filter, simultaneously
for all three filter characteristics. The full CCW position

CW position to the highest frequency.

(CV Input) Cutoff 2

CV input for cutoff modulation. This input reacts to bi­polar CVs, internally only a 5V peak-to-peak signal is
processed, so every CV signal exceeding a voltage of
5Vpp will have to be attenuated to use the full range
of the CV input.

Input Attenuator / Gain 3

Defines the amplitude of the signal that will travel into
the filter. At the counter-clockwise (CCW) position
there will be no signal going into the module at all, at
around 9 o’ clock the signal will be at unity gain and at
full clockwise (CW) position the signal will be boosted
by about +6dB

(Audio Input) AUDIO IN 4

Audio input to the filter. There’s plenty of gain here,
so take care when setting the input level if you do
not want to distort your signal. Overdriving the input
can get you amazingly rich and experimental sounds
though, so try it out once and see if you like it!

(Audio Outputs) AUDIO Out 5

These are the three outputs for the corresponding
filter characteristics. All three outputs are available
at the same time without
around. When changing the cutoff frequency or the
resonance of the filter you change these features for
all of the outputs simultaneously.

the need to switch anything

6 RESONANCE

Sets the Q of the filter, better known as resonance. The
resonance of a filter determines the gain increase of the

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signal at the cutoff frequency. Set it low (CCW) to leave
the signal gain at cutoff frequency at zero and turn it
CW to hear plenty of resonance at the given cutoff fre­quency.
Be aware of the fact that the filter will start self-oscil­lating when you are at or near maximum resonance!

7

Resonance (CV Input)

CV input for resonance (Q) modulation. It has the same
specifications as the Cutoff CV input.

8 Select (CV Input)

CV input to select which output will be present on the Mix
Out audio output. This CV input accepts 0 – 5V (unipolar).
If there is no CV signal sent into the input in the Select
jack, the attenuator acts as a normalled CV source from
0 – 5V for manual sweeps through the filter types.

9

Mix Out (Audio Output)

The Mix Out is a special output of the SVF-201 which
contains all three of the above outputs (LP, BP and
HP). You can sweep continuously through these three
outputs with a control voltage signal from 0 – 5V. This
output has more internal gain than the three different
single outputs, so signals taken
have more overdrive / distortion than their respective
partners. The signal levels themselves are identical
though.

from this output will

All the best from Berlin,

The KOMA Elektronik Team

Wouter Jaspers Christian Zollner

Robert Kunz Hayden Moskowitz

Getting Started

1. Unpack your new gadget

The package comes with the SVF-201 filter module, a 16-pole
ribbon cable with connectors, a small bag with four screws
and washers for front panel mounting and this manual.

2. Connections

First off; be sure that the bus board of your system is un­powered. Take the connector cable and insert it into the bus
board of your modular system. Be very careful when doing so
because it is easy to shift the connector and place it incor­rectly.
The red marked side needs to be connected on the lower side
of a Doepfer bus board and on the marked side of the module
(-12V rail). If attached correctly the keyed header will have
the right orientation for keyed power systems (e.g. uZeus).
See the rear panel picture for more clarity.

3. Power up

Rear Panel Controls

Warning!

Please do

not touch or change

the four trimmers on the

top as they are already

set to best filter behaviour

and it is complicated

to reset them after you

turned them (also just a

little bit), so please just

safe yourself the hassle

and stay away from these

trimmers!

Gate

CV

+5V

+12V

GND
GND
GND

-12V

Red

stripe

here!

-12V

1 +5V rail choice

If you have a +5V power supply on your bus board rails
and you want to use it with the KOMA Elektronik SVF-201
then you can change the second jumper setting from
‘Onboard’ to ‘Bus’. Don’t worry, the two +5V rails can
never be connected together, regardless of how you
place the jumper.

2 ISP programming header for Mix Out

If you have access to an ISP programmer and you are
familiar with programming micro controllers you can use
the 6-pin ISP header for connecting your programmer to
the module. You will find the pre-loaded code as well as
some alternatives on our homepage at www.koma-ele­ktronik.com

3 LED CORONA

If you don’t like the white light around the Cutoff knob
simply take out the jumper above ‘LED Corona’ (and try
not to loose it!).

4 POWER CONNECTION

Always make sure you align the red stripe on the power
connector to the red stripe marker on the module. To be
extra safe, make sure that the cable you are using is
correctly wired, which means that one connector faces
up and the other down when you hold the cable in front
of you with the flat side up.

Power up your system and check if all supply rails are up and
running (+/-12V and possibly +5V), often there are indication
LEDs on the bus board showing if the rails are working prop­erly. When the power is connected properly, a white light – a
nice nimbus - underneath the big Cutoff knob should light
up.

Features

The use of the FT201 is pretty straight forward. There is the
CUTOFF knob with which you set the cutoff frequency for the
filter, simultaneously for all three filter characteristics. Fully
counter-clockwise sets the cutoff frequency to the lowest
and fully clockwise to the highest frequency.

The RESONANCE knob sets the Q of the
as resonance. The resonance of a filter determines the gain
increase of the signal at the cutoff frequency. Set it to low
(CCW) to leave the signal gain at cutoff frequency at zero
and high (CW) to hear plenty of resonance at the given cut­off frequency. Be aware of the fact that the filter might start
self-oscillating when you are at or near maximum resonance.

filter, better known

Filter Modes

LOWPASS (LP OUT) BANDPASS (BP OUT) HIGH PASS (HP OUT)

MIX OUT

(LP/BP/HP MIXED OUT)

Amplitude

The MIX OUT is a unique output that combines all filter types.
You can sweep through from lo pass to band pass to hi pass
with the SELECT potentiometer. The SELECT potentiometer is
also able to be controlled via CV.

Imprint

KOMA Elektronik GmbH
is a subsidiary company of KOMA Elektronik B.V.

Managing Director:
Christian Zollner & Wouter Jaspers
Registered Office: Berlin, Germany

Court of Registration:
Amtgericht Berlin-Charlottenburg
Registernummer : HRB 145453
VAT ID: DE285522050

KOMA Elektronik GmbH

Mahlower Strasse 24
12049 Berlin-Neukölln
Germany

01

02

03

05

04

Basic Settings

DISTORTED
LOWS

——

When the input gain is all the way up,
the signal is distorted along with high
resonance, creating a gritty sound.

Adjust the CUTOFF to tune the
resonance to your incoming notes.

3 CHANNEL
MIXER

——

Take each output channel into its own
channel on a mixer to blend between
each filter type manually.

Use all three signals at once with
various levels to find new timbres
and textures.

OSCILLATOR

——

Patch the HI PASS Audio Output back
into the AUDIO Input to create an
oscillator.

Adjust the CUTOFF by hand or via CV
to change the pitch.

SUB BASS
RESONANCE

——

When using the HI PASS output at a very
low cutoff and high resonance, sub
bass frequencies are added around the
Q frequency.

Adjust the CUTOFF to tune
the resonance to your song.

FILTER TYPE
SWEEP

——

Patch an LFO into the SELECT CV input to
sweep through the different filter types
creating completely new sounds!

It can result in some formant-like
sounds. Crank the Input and distort it
even more if you like!

AUDIO out

SVF 201

——

ANALOG STATE VARIABLE
FILTER

AUDIO IN

OUT to mixer

AUDIO IN

AUDIO out

Hint*

Try patching in a full frequency signal such as a drum pattern or loop and take the
output from the MIX OUT. Adjust SELECT by hand or with a CV signal to create your own

crossover network for further processing the specific frequency range.

Meanwhile, use the LP OUT for an unaffected signal.

LFO IN

AUDIO outAUDIO IN

AUDIO IN

AUDIO out

BD 101

——

ANALOG GATE

/DELAY

The concept of control voltage (CV) is not hard to understand: instead of turning
a knob on your pedal, you simply connect a voltage – the control voltage – to the
corresponding CV input that does the job for you. All of the CV inputs theoretically
accept control voltages from -100V to +100V though a range from -5V/-12V/-15V to
+5V/+12V/+15V is more common and usable.

BIPOLAR CV SIGNALS

OUT TO MIXER

Tips & Tricks

USING THE INPUT

The Input Attenuator / Gain control defines the amplitude of the signal that will travel
into the filter. At a counter-clockwise (CCW) position there will be no signal going into
the module at all, at around 9 o’ clock the signal will be at unity gain and at full clock­wise (CW) position the signal will be boosted by about +6dB.

USING THE MIX OUT

The Mix Out is a special output of the SVF-201 which contains all three of the outputs
(LP, BP and HP). You can sweep continuously through these three outputs with a con­trol voltage signal from 0 – 5V. The diagram on the front side of this manual (under
FILTER MODES, far right) shows the corresponding loudness curves of the filter char­acteristics in correlation with the CV input. Low pass appears at 0.25V to 2.25V, pure
bandpass between 2.25V and 2.75V and from 2.75V to 4.75 you’ll get high pass as an
output signal. All outputs crossfade into each other.

WarrantyCV Theory

KOMA Elektronik warrants its products to be free of defects in materials / workman­ship and conforming to specifications at the time of shipment for a period of two
years from the date of purchase. During the warranty period, any defective products
will be repaired or replaced at KOMA Elektronik’s option, on a return-to-factory basis.
This warranty only covers defects that KOMA Elektronik determines are no fault of
the user.

RETURNING YOUR PRODUCT?

You must obtain prior approval in the form of an RMA (Return Material Authorization)
number from KOMA Elektronik before returning any product. Email support@koma-el­ektronik.com to request the RMA number. All products must be packed carefully and
shipped with all the originally sent content. Sorry, the warranty will not be honored
if the product is not properly packed. Once you have received the RMA number and
carefully packed your product, ship the product to KOMA Elektronik and include your
return shipping address.

The incoming bipolar CV signal is shifted around the voltage that you select with the
corresponding knob. Example: if you insert a -5V to a +5V sine wave while adjusting
the bias:

BIPOLAR CV SIGNALS

A similar thing happens to unipolar CV signals: their point of origin (0V) is shifted by
the amount set with the corresponding knob. In other words: you add the voltage of
your knob to the voltage of your incoming unipolar CV signal.

UNIPOLAR CV SIGNALS

HOW TO CLEAN YOUR SVF 201

Clean the front panel with a cloth and rubbing alcohol.

Technical specs

CASING

2mm Aluminum front panel, powder
coated white with silkscreen printing.

DIMENSIONS

3U Eurorack module
12HP wide
40mm deep

CONNECTORS

4 Audio outputs: low pass, band pass,
high pass, mix.
3 CV inputs: cutoff, resonance, mix.

POWER REQUIREMENTS

80 mA @ +12V.
11 mA @ -12V.

WHAT WILL WE DO?

Once received, we will examine the product for any obvious signs of user abuse or
damage as a result of transport. If the product has been abused, damaged in transit
or is out of warranty, we will contact you with an estimate of the repair cost.

Warranty work will be performed and KOMA Elektronik will ship and insure your prod­uct to your address free of charge.

HOW TO INITIATE YOUR WARRANTY?

Please initiate your warranty online by sending an email to :
[e-mail].

If you do not have web access, fill out your personal information on a letter
and mail to:

KOMA Elektronik GmbH

Mahlower Straße 24,
12049 Berlin-Neukölln
Germany

SHIPPING WEIGHT

250 gram / 0.55 lbs.

Graphics by: www.rabadaun.com