Model 257 Dual Control Voltage Processor consists of two identical sections, each of which permits several applied control voltages to define a single output voltage according to the equation: (Va * K) + ((Vb * (1-M)) + (Vc * M)) + Voset = V_out
The algebraic manipulations possible with this module include addition, subtraction, scaling, inversion, and multiplication. Also incorporated is the capability of using one control voltage (M) to transfer control from one applied voltage (V_b) to another (V_c).

Functions
- Attenuverter : Va is the voltage input a for attenuverter (left jack on the panel) K knob can scale the incoming Va voltage either positively or negatively
- Crossfader : Vb is the voltage input b for the left side of the crossfader (second jack from the left) +.5 switch adds 5 volts to the input of Vb Vc is the voltage input c for the right side of the crossfader (fourth jack from the left) M scales Vb from 1 to 0 based on the position of M knob M scales Vc from 0 to 1 based on the position of M knob The middle CV input at M/M can crossfade between Vb and Vc (third jack from the left) The M knob and M CV added together to control crossfade position
- Offset : Voffset Adds 0 - 10 volts to any combination of Va + Vb + Vc
- Output Vout is the combined voltage of the attenuverter, crossfader and oset (right jack on the panel)
Spec
Size : 14 HP
Depth : 25mm
Power : +12V / 45mA ; -12V / 22mA