Owner's manual

Theory of Operation | 7
The shapes of the distortion curves are also different from standard
distortions. Normally, as the input signal voltage rises, the output voltage
also rises, but begins to level off and finally pins (or clips) at a maximum
value. With a foldback curve, for large enough values of the input, the out-
put will begin to decrease. With more extreme amounts of foldback, after
decreasing for a while, the output can begin to increase again. Maximum
foldback has many regions where the output alternates between increas-
ing and decreasing. This kind of distortion curve adds a lot of high fre-
quency content to the output. It also can provide a lot of control over the
sound based on the level of the input signal. With heavy foldback, chords
containing only octaves and fifths tend to sound best. Other intervals can
cause some strange, although not necessarily undesirable sounds.
Using a special shape of the distortion curve, strong second harmon-
ics can be created, sounding like a note an octave higher. Rolling off the
guitar tone control will help maximize the octave impression. Complex
chords don’t typically work well for octave settings. The result is very sen-
sitive to the input signal level (as long as the SUSTAIN and DRIVE controls
are not set too high) and can give a sort of auto-wah effect. Try dialing
down the guitar volume for some interesting effects.
A conventional distortion effect tends to turn the guitar signal into square
waves. Playing harder only makes the transition from negative clip-
ping to positive clipping a little bit steeper. With our foldback and octave
algorithms, a slightly higher input can have a radical effect on the shape
of the output signal.