Moog MF102 User Manual

Understanding and using your

moogerfooger®

MF-102 Ring Modulator

Welcome to the world of moogerfooger® Analog Effects Modules! Your Model MF­102 Ring Modulator is a rugged, professional-quality instrument, designed to be equally
at home on stage or in the studio. Its great sound and classic effects come from the
state-of-the-art all-analog circuitry, designed and built under Bob Moog's personal
direction.

Your MF-102 is a direct descendent of the original modular Moog™ synthesizers. It
contains three complete modular functions,- a Ring Modulator, a voltage-controlled
Carrier Oscillator, and a voltage-controlled dual-waveform Low Frequency Oscillator
(LFO). All performance parameters are voltage-controllable, which means that you can
use expression pedals, MIDI-to-CV converter, or any other source of control voltages to
'play' your MF-102.

While you can use it on the floor as a conventional effects box, your MF-102 is much
more versatile and its sound quality is higher than the single fixed function "stomp
boxes" that you're probably accustomed to. You will find that your MF-102 is a deep
musical resource. It will give you an amazing variety of new sounds and will become
your creative companion as you explore its functions.

The following pages will first tell you how to hook up your MF-102 and set the panel
controls for the 'basic' setup. Next, we'll explain how the modular functions in your MF­102 work. After that we'll go through the panel features and give you suggestions on
how to use your MF-102 in specific applications. At the end of this booklet you'll find
technical specifications, service and warranty information, and information about
Moog Music.

GETTING STARTED

Here are some simple instructions on how you can quickly plug in and try out your MF-

102.

1. Unpack your MF-102. You can place it on a table or on the floor. We suggest that
you place it on a table while you become familiar with its features.

2. Check that the power adaptor is designed to supply +9 volts and is rated at your
country's standard power voltage (120 volts A.C. for the United States and Canada; 100
volts for Japan; and 220 volts A.C. for most other countries). Plug the power adaptor's
cord into the MF-102's '+9V' jack. Then plug the power adaptor itself into a power
voltage receptacle.

Figure 1. Basic connections: Instrument to AUDIO IN, monitor amp to AUDIO OUT, and power adaptor to +9V.

3. Note that the BYPASS light is on. It will light up either red or green. Red indicates that
the MF-102's ring modulator is off-line (bypassed), while green indicates that the ring
modulator is on-line. 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.

4. Connect an instrument cable from the MF-102 AUDIO OUT jack to a line-level input
of your amp or mixer. Turn the volume control on your amp down but not off.

5. You can feed virtually any instrument-level or line-level signal through your MF-102.
Examples are guitar, bass, keyboard, theremin, drum machine, or Effects Send output
on your mixer. Connect an instrument cable from your signal source to the MF-102
AUDIO IN jack. Play your instrument (or turn on the signal source). Turn the DRIVE control
clockwise until the LEVEL indicator lights up yellow most of the time.

6. The BYPASS light should still be red. Continuing to play your instrument, adjust the
volume control of your monitor amp until the loudness is comfortable. Your instrument
should sound clean and undistorted.

7. Now set the MF-102 panel controls as follows (See Figure 2):

AMOUNT 2
RATE 6.4
MIX 10
FREQUENCY 250
Left Switch "Sine Wave"
Right Switch HI

Figure 2 - Basic settings for becoming familiar with your MF-102.

Press the stomp switch. The BYPASS light will now turn green. Play your instrument. Your
instrument's signal is now going through the ring modulator. Listen to how the MF-102
affects the quality of your instrument's tone. You will hear a distinct vibrato. Note that the
AMOUNT knob affects the strength of the vibrato and the RATE knob affects the vibrato's
speed.

8. In the next section we'll explain exactly how a ring modulator works, what the carrier
oscillator and LFO do, and how the controls work. For now, get a feel for the controls by
experimenting with different settings.

HOW A RING MODULATOR WORKS

Let's start with some definitions. Please read this section carefully, as it will help you to
understand the basic ideas underlying ring modulation.

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 the sound its characteristic tone
color, or timbre. We can represent a musical sound either as a waveform or as a
spectrum. The waveform is a time graph of the actual shape of the vibration, while the
spectrum shows how strong each of the sound's harmonics is. See Figure 3.

Figure 3 - A musical sound can be represented as a waveform (top graph) or as a spectrum (bottom graph).

The waveform of a single harmonic is called a sine wave. The spectrum of a sine
wave is just a single line. Figure 4 shows the waveform and spectrum of a 500 Hz sine
wave, while Figure 5 shows the waveform and spectrum of a 100 Hz sine wave. If you
listen to a 500 Hz sine wave, you hear a pitch nearly an octave above middle C, with a
mellow, muted quality, like a flute or a whistle. A 100 Hz sine wave also sounds mellow
and muted, but its pitch is more than an octave below middle C.

Figure 4 - Waveform and spectrum of a 500 Hz. sine wave. Figure 5 - Waveform and spectrum of a 100 Hz sine

wave.