From the Encore Electronics website:
The Encore Electronics Frequency Shifter is a hybrid analog implementation of the sought-after frequency shifting effect. A RISC microprocessor is used to generate a highly stable quadrature oscillator which is then used with analog multipliers to generate the frequency shifting effect. The quadrature oscillator outputs are analog signals from the output of a DAC and the audio input signal is never digitized and stays entirely in the analog domain.
This unusual device will produce effects ranging from the subtle to the extreme. For example, by employing the simultaneous up and down shift outputs, the on-board feedback controls, and a slight amount of shift with the fine-shift control, a stunning stereo infinite phasing effect is possible. Small shifts with the fine shift control will also produce lush vibrato and rotating-speaker-like effects. Larger amounts of shift can result in unusual and often bizarre inharmonic modifications of an input signal that must be heard to be believed.
The frequency shifter can seriously warp any input signal, from keyboards to guitars to vocals to drum machines.
The Encore Frequency Shifter features two frequency shift controls (coarse and fine), and is a through-zero design. The UP output will shift up when the coarse knob is greater than 12 o’clock, and will shift down when less than 12 o’clock.
It also features an input scaler capable of handling signals from line-level up to modular levels, two feedback controls for added sonic variety, and a CV input scaling control. It also has two controls to adjust the level of the quadrature oscillator’s outputs. There are two inputs (one for audio signal and one for a frequency shift control voltage) and two outputs, one for up-shifted signal and one for down-shifted. The Encore Frequency Shifter is capable of continuous frequency shifting from 0.075Hz up to over 2000Hz. Carrier feedthrough is more than 50dB down with a properly scaled input signal; no companding is employed.
The frequency shifter operates by altering the frequencies of an input signal. The device shifts all frequency components of the input signal by an equal number of Hz. With this kind of shifting the harmonic relationships in the signal are not preserved. This is unlike a standard pitch shifter, which shifts all frequency components of an input signal by the same ratio, thus preserving the signal’s harmonic intervals.
Modifications: Jack panel hardware changed to match the Switchcraft washers and nuts used on other MOTM modules.