Operation Manual

6.87 Toggle 146
6.87 Toggle
The Toggle module is a clock divider. This module has two inputs and one output. The first input is
the clock signal to be divided. The second input is used to reset the circuit. The output is the input
signal with a frequency divided by two. To perform this operation properly, this module should
only be used with clock signals in the first input.
6.88 Tone wheel
The Tone wheel module is used to build combo organs. It is
mainly based on a Hammond tone wheel but also allows to generate
different tone colors ranging from flute-like sounds (Hammond) to
reed-like sounds. This module has two inputs, a gate and a pitch
signal (1 Volt/octave), and one output, the signal produced by the
tone wheel.
Tuning
The nine buttons on the front panel are used to determine the note
played by the tone wheel. The different note possibilities follow har-
monic relationships and are labeled in feet (as a reference to pipe lengths in organs). When the
8
´
button is pressed, the tone wheel will play the note corresponding to the signal received on the
pitch input of the tone wheel (usually connected to the pitch output of a Keyboard module, con-
vention is 1 Volt/octave). When the 16
´
button is pressed the output is one octave below. The other
buttons, 5 1/3, 4, 2 2/3, 2, 1 3/5, 1 1/3, output a note a fifth, an octave, a twelfth, 2 octaves, 2 octaves
and a major third, 2 octaves and a fifth and 3 octaves above the pitch input respectively. The pitch
of the output can be fine tuned by plus or minus 3 semitones using the fine knob.
Switch effect
In addition to the sound of the tone wheel itself, the timbre of original hardware electric organs
also contains very typical noise components. This noise is due to two separate effects. First, when
a key is depressed on an organ, mechanical imperfections result in a slight random triggering delay
between tone wheels which has the effect of blurring the attack. The second component is a contact
noise. The Tone Wheel module reproduces this characteristic behavior of organs. When the switch
selector is in the left position there is no noise and the random delay is minimal. In the right
position, the amount of noise and random delay are maximum