Modulator section.
The MIX knob crossfades from the direct (unmodulated) signal to the signal from the
ring modulator output. You hear only the direct signal when the knob is
counterclockwise, and only the ring-modulated signal when the knob is clockwise. You
crossfade smoothly from one signal to the other as you turn the knob.
The FREQUENCY knob and the LO-HI switch determine the frequency of the carrier
oscillator. The FREQUENCY knob has two calibration ranges: 0.6 Hz to 80 Hz, and 30 Hz
to 4 kHz. The LO-HI switch setting determines which range is on.
Audio Input Level
The DRIVE control and the LEVEL light are part of the audio input level circuitry.
The DRIVE control adjusts the input gain. With this control you can set the right input
gain for virtually any instrument or line-level signal source. Turn this control
counterclockwise for strong input signals, and clockwise for weaker sound sources. The
DRIVE control is always active, even when the MF-102 is in BYPASS mode.
The LEVEL light tells how strong the input signal is after being adjusted by the DRIVE
control. As the signal level increases, the light goes from off, to green, to yellow, and
finally to red. Very weak signals do not light up this light at all. When the light is green,
the signal is below the level that results in audible distortion. When the light is yellow,
some low order distortion may be audible, giving the sound a subtle warm analog
quality. When the signal is strong enough to drive the light into the red, the distortion at
the output becomes stronger and more distinctly audible. Watch this light when you set
the DRIVE control for the desired effect.
Figure 9 - Block diagram of the MF-102, showing panel controls, switches, and jacks. (Pedal/control jacks are not
shown, but perform the same functions as the control knobs.)
EXPRESSION PEDALS AND VOLTAGE CONTROL
You now know what each of the rotary control knobs does to the sound of the MF-
102. With the exception of DRIVE, each knob has an expression pedal/control input
which duplicates its effect. This enables you to plug in up to four expression pedals to
play the MF-102 with your feet as well as with your hands. The moogerfooger EP-1
Expression Pedal is designed for this purpose. Or you can use expression pedals with
