Moog MF105 User Manual
Understanding and Using
Your moogerfooger®
MF-105 MuRF™
TABLE OF CONTENTS
Getting Started............................................3
Frequencies and Filters...............................5
The MuRF’s Filters.....................................7
Envelope Generators.................................10
Sequencers and Pattern Generation..........11
The MuRF’s Animation............................11
The MuRF’s Tap/Step Input.....................13
Audio Level Controls and Mixing............14
Using Both Outputs Together..................14
Expression Pedals and Voltage Control....15
Some Typical Setups.................................16
Technical Information...............................17
Limited Warranty......................................19
MF-105 Specications.............................20
Appendix A - the MuRF’s Patterns...........22
Welcome to the world of moogerfooger® Analog Effects
Modules! Your model MF-105 MuRF is a rugged, professionalquality instrument, designed to be equally at home on stage or in
the studio. Its great sound and jaw-dropping effects come from
the state-of-the-art analog circuitry, designed and built under Bob
Moog’s personal direction.
Your MuRF is a direct descendent of the original Moog™
modular synthesizers and professional rack effects. It contains two
basic functions: an 8-band array of resonant bandpass lters, and
a pre-programmed “Animation” module that generates sequences
of envelopes that modulate the levels of the 8 lters. Several of
the performance parameters are voltage-controllable, which means
that you can use expression pedals, MIDI-to-CV converter, or any
other source of control voltages, such as other moogerfoogers, to
‘play’ your MuRF.
While you can use it on the oor as a conventional effects box,
your MuRF is much more versatile and its sound quality is higher
than the single xed-function “stomp boxes” that you’re probably
accustomed to. The MuRF is an astoundingly versatile effects
device, you will nd it provides an incredible variety of effects.
You will nd that your MuRF is a deep musical resource and will
become your creative companion as you explore its possibilities.
The following pages will rst tell you how to hook up your
MuRF and set the panel controls for the ‘basic’ setup. Next, we’ll
explain how the functions of your MuRF work. After that we’ll
go through the panel features and give you suggestions on how
to use your MuRF in specic applications. At the end of this
booklet you’ll nd technical specications, service and warranty
information, information about Moog Music and diagrams of the
MuRF’s Animation patterns.
GETTING STARTED
Here are some simple instructions on how to quickly plug in and
try out your MF-105.
1. Unpack your MF-105. Place it on a table while you become
familiar with its features.
2. Check that the power adaptor has a nominal rating of +9 volts,
providing at least 300 mA (milliamperes) of current and is also
rated at your country’s standard power voltage (120 volts A.C. for
the United States and Canada; 100 volts A.C. for Japan; and 220
volts A.C. for most other countries). Plug the power adaptor’s cord
into the MF-105’s ‘+9V’ jack. Then plug the power adaptor itself
into a power voltage receptacle. Note the MuRF uses a different
power supply than other moogerfoogers, which is only rated at
200mA. Using a 200mA moogerfooger power supply may result
in hum, distortion, and other less than desirable audio artifacts.
Make sure to use the proper power supply.
3. Note that the BYPASS light is on. It will light up either red or
green. Red indicates that the MF-105’s effect is off-line (bypassed),
while green indicates that
the effect is on. Pressing the
‘stomp switch’ will toggle the
BYPASS light between red
and green. For now, leave the
BYPASS light on red.
Refer to Figure 1 for steps 4.
and 5.
Figure 1 - Basic Connections to MuRF
4. Connect an instrument cable from the LEFT/MONO jack to a
line-level input on your amp or mixer. Turn the volume control on
your amp down but not off.
5. Connect an instrument cable from your signal source to the
AUDIO IN jack. You can feed virtually any instrument-level or
line-level signal through your MF-105. Examples are guitar, bass,
keyboard, theremin, drum machine, or Effects Send output on your
mixer. Play your instrument (or turn on the signal source). Adjust
the volume control on your monitor amp so that the sound level is
comfortable.
6. Now set the MF-105 panel
controls as follows (See Figure
2):
PATTERN 2
ENVELOPE 2
RATE 6
MIX 10
BANK A/B A
Filter Sliders 1-8 All the
way up.
Figure 2 - Basic Settings
Press the stomp switch. The BYPASS light will now turn green.
Playing your instrument, set the DRIVE control so that the DRIVE
indicator lights up yellow most of the time. You will also hear the
ltered signal. Adjust the OUTPUT control so the MuRF’s effected
signal is about the same loudness as the bypassed signal.
7) Continue to play your instrument, playing sustained sounds
like ringing chords. Your instrument’s signal is going through the
MuRF’s lters. Listen to how it affects the quality of your
instrument’s tone. You will hear the level of each of the 8 lters
being turned up and down automatically in sequence by the
Animation at a tempo determined by the RATE control. Note that
changing the ENVELOPE control affects the shape that turns the
lters up and down. The PATTERN rotary switch selects different
patterns that dictate the sequence that turns the Filters up and down
automatically. The MIX control is used to blend the direct sound of
your instrument with the effected sound.
8. In the next sections we’ll explain exactly how the MuRF’s
Filters work and what the Animation does. For now, get a feel for
the controls by experimenting with different settings.
FREQUENCIES and FILTERS
Let’s start with some denitions. Please read this section
carefully, as it will help you to understand the basic ideas behind
the MF-105 MuRF’s lters.
Sound is a vibration of the air. The speed of vibration is called
the frequency. It is measured in Hertz (Hz). One Hz is one
vibration per second. We hear vibrations from 20 Hz to 20,000 Hz.
Musical sounds generally have many frequency components.
They’re called harmonics, or overtones, or partials. They are
what give a sound its characteristic tone color, or timbre. A graph
showing the strength of each of a sound’s harmonics is called
a spectrum. A typical spectrum of a musical sound is shown in
Figure 3.
A lter is a signalmodifying device that colors
a sound by emphasizing
some parts of the audio
Figure 3 - Typical spectrum of a musical sound.
spectrum and attenuating
(cutting down) other parts. In general, a lter has a ‘quality’ of
its own which is superimposed on the tone color of the original
sound. Some types of lters (like the bass and treble controls on
your sound system) have subtle, gentle effects on a sound’s timbre.
Other types of lters have stronger and more dramatic effects, and
are frequently used as vital elements in the music-making process.
Strong lters include phasers, angers, and wah-type resonant
lters.
A graph showing what a lter does is called the lter’s frequency
response. The horizontal axis is frequency. The vertical axis is the
lter’s gain. A gain of “1” (unity) means that, at that frequency, the
output of the lter is just as strong as the input. A gain of less than
unity means that the lter’s output is attenuated at that frequency,
while a gain of greater than unity means that the output is actually
greater than the input.
Figure 4 - Frequency responses of typical lters.
Figure 4 shows examples of the frequency response
characteristics of two common types of lters: (a) a lowpass lter,
which passes frequencies without attenuation up to a so-called
‘cutoff frequency’, and attenuates the frequencies above cutoff; (b)
a resonant lter, which emphasizes frequencies around the lter’s
‘center frequency’.
Both of these lter types are widely used in contemporary music
performance. Each of them has its own distinct sound, a large part
of which is directly related to the shape of its frequency response
graph. The rst type is embodied in the moogerfooger MF-101
lowpass lter, and the second type is embodied in the MuRF..
There are eight separate resonant lters in your MF-105.
The MuRF’s FILTERS
The MuRF’s eight resonant lters have a xed center frequency,
shown on the legend underneath the lters’ sliders. Their
frequencies are: 200 Hz, 300 Hz, 450 Hz, 675 Hz, 1 KHz, 1.5 KHz,
2.2 KHz, and 3.4 KHz.
Each lter has a slider that adjusts the gain of that lter. In this
respect, the MuRF resembles a graphic equalizer. When a lter’s
slider is all the way down, the gain for that lter is zero, and the
lter’s output is zero. When the slider is all the way up, the lter’s
output is maximum. However – the resemblance to a graphic EQ
ends there. The MuRF’s lters have characteristics that set them far
apart from a graphic equalizer. First, they are resonant lters. They
boost the signal at the center frequencies of the lters. Second,
they are tuned so they don’t overlap. A graphic equalizer will
theoretically not color the signal at all when all the sliders are set to
the same level. The MuRF’s resonant lters on the other hand color
the signal a great deal, adding warm analog resonances at pleasing
intervals through out the frequency spectrum. We’ll now show
how the MuRF’s lters affect your MF-105 frequency response.
We will always start with this ‘basic’ panel setup, which is:
Figure 5 - Basic Settings for checking out the
lters.
1) Set each of the lters’
sliders to all the way up.
2) Switch the PATTERN to
Bank A, Pattern 1. Pattern 1
turns off the Animation so you
can hear the effect of just the
lters.
3) Make sure the effect is on,
and MIX is at 10.
4) Connect just the “left/mono”
output to your amplication.
You may want to experiment with the panel controls and switches
as we discuss each of the parameters.
5) Now, play a bright, sustained sound, preferably of low pitch
into the MuRF - keep in mind that lter effects work by removing
frequencies, so you must have a bright sound to hear the effect!
Figure 6 shows the MF-105’s basic frequency response, the
response that you hear when the panel controls are set up as in the
basic setup. Note that there are 8 resonances – they impart warmth
and color to the sound. For a moment press the bypass switch and
turn the effect off. Note the change in character of the sound. Now
switch the effect back on.
Figure 6 – Frequency Response of MuRF in Basic Setup
6) Now turn all the sliders down except the lowest one. Figure 7
shows the frequency response of just the lowest lter. Experiment
by turning each slider up one at a time, while the rest of the sliders
are all the way down. Pay careful attention to the sound of each
lter. When you have learned the sound of each individual lter,
try various combinations, such as the bottom two and top two.
Note that even without
Animation, the MuRF is
a VERY POWERFUL
lter bank with many
possibilities to sculpt your
tone!
Figure 7 – Frequency response of 200 Hz Filter
7) The Filters’ resonant frequencies can be shifted up and down
by a small amount to create an effect similar to phasing. Figure
8 shows a graph that portrays the results of shifting a resonant
lter’s center frequency. In the MuRF this can be done two ways,
depending on the position of the BANK slider switch. The switch,
located below the PATTERN selector switch is labeled BANK A
or B/LFO. When the slider is in the “A” position, the lters’ center
frequencies can be shifted by an expression pedal (such as the
Moog EP-1) or CV plugged into the LFO/SWEEP Jack.
To hear how
this works, return
to the basic setup
described in Figure
5. Plug a Moog
Figure 8 - Resonant Frequency shift
EP-1 into the LFO/
SWEEP control
input. Then, as you play into the MuRF, rock the EP-1 back and
forth. You will hear the lters’ frequencies shift with the motion of
the pedal.
When the BANK slide switch is in the B/LFO position, an LFO
(Low Frequency Oscillator) shifts the frequencies of the lters as
a group up and down automatically. The LFO is a sine wave. The
rate is determined by the pattern, or an expression pedal (EP-1 or
equivalent) or CV connected to the LFO/SWEEP jack.
To hear the effect of the LFO on the MuRF’s lters, return to
the basic setup outlined in gure 5, then move the BANK slider
switch to “B/LFO”. Now as you play through the MuRF, you’ll
hear the lters swept up and down automatically. To change the
speed of the LFO, plug a Moog EP-1 expression pedal into the
LFO/SWEEP Control Input. The EP-1 can now slow down or
speed up the LFO.
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