User Manual
AMP BIASING FEATURE
The biasing feature emulates Class-A tube and transistor amplifier tuning. Biasing is a symmetry adjust-
ment that sets the quiescent operating point of a tube or transistor in order to achieve a linear response with
least distortion. By increasing the bias (DC offset) a tube/transistor can be pushed into asymmetrical saturation.
While Vortices already provides enough gain to produce saturation/compression on its own, the output
is symmetrical as long as the input signal is also completely symmetrical about 0V. For instance, +/-5V is sym-
metrical while +6V/-4V is asymmetrical.
The tonality of symmetrical saturation/compression exhibits a dominance of 3rd order (ODD) harmonics.
However, if one half of a waveform saturates more than the opposite half, in an asymmetrical manner, this
produces an increased level of 2nd order (EVEN) harmonics.
Vortices can produce asymmetrical saturation/compression when the input source is biased (offset) with
a positive or negative DC voltage. This is accomplished by using an external CV processor or mixer with a volt-
age offset adjustment or externally summing an audio source with an envelope or LFO (for a time varying
effect), before patching into one of Vortices’ inputs.
If you do not have a free external mixer with or without an offset adjustment, an alternative tonal struc-
ture can be achieved by patching an envelope or LFO into an unused channel of the same mix bus on Vortices.
In this case, the signal is clipped by the internal hard limiter and produces crunchier asymmetrical distortion
effects.
In all amp biasing cases, the total output symmetry remains unaffected and therefore every channel can
be biased without pushing the summed mixer outputs beyond the maximum headroom of ~23Vpp.
AUDIO
OPTIONAL CV
OUTPUT TO VORTICES
(AMP BIASING) OFFSET
OPTIONAL CV
ALTERNATIVE
DISTORTION
INTO AN UNUSED INPUT
5
5