Korg Pa4X User Manual page 719

b, f: Saturation [%]
With higher settings of this value, the waveform will change at high gain
levels, tending to cause distortion. Lower settings of this value will produce
linear response.
Out
c: Tube1 Bias
This expresses the effect that changes in vacuum tube bias have on the dis-
tortion of the waveform. Higher settings of this value will produce distortion
even at low gain levels. Since this will also change the overtone structure,
you can use it to control the tonal character.
Out
d: Tube1 Phase
With the Wet Invert setting, the phase of the signal will be inverted between
stage 1 and stage 2. Since "Bias" is applied to the inverted signal in stage 2,
this will change the tonal character.
Mic/Pre Amp - Saturation
Saturation = 0
Saturation = 50
Saturation = 100
In
Bias = 0
Mic/Pre Amp - Bias
Bias = 100
Bias = 50
Bias = 0
In
Satulation = 50
Effect parameters |705