PH-4 is a generator with four signal outputs. all outputs has the same signal frequency, strength, and shape, but with 90 degrees phase shift between any two adjacent outputs. Consequently, the phase relation counted from first to fourth output is; 0, 90, 180 and 270 degrees.

The main duty of the PH-4 is to controll four identical modulated devices. One example; the phase shifter (phaser) is a signal processing device which substitute phase change components applied to an external audio source for the frequency components of the tone. The characteristic of multiple phase shifters are controlled by the PH-4 so that the phasing effect doesn't simply swing back and forth as usual, but sweeps up and down eternally. The same effect can be acheved with filters, oscillators, and amplifiers.

Rate (or speed) can be controlled manually and by an external CV signal. The modulating waveform is selected by the switch: sine or triangle. The output level is controlled by an external CV signal. The voltage offset can be controlled with the dedicated knob or an external CV signal.