Analogue Systems RS-240 Bode Freq Shifter

Faithful reproduction of the legendary and rare analog frequency shifter from the Moog modular system, designed by Harald Bode. The RS-240impresses with features like exponential and linear shifting scales, integrated squelch circuitry, very clear sound and several audio outputs ... yeah, and by that HUGE knob ;)

Amount of frequency shift is controlled by CVs and manually, on the one hand by the big knob and on the other hand by the rotary control that selects between different scales:

• ZERO: no frequency shift
• EXP: exponential frequency shift for unusual effects. The input frequency will be multiplied by a certain factor. e.g. when doubling the control voltage the frequency will be shifted one octave upwards (double frequency) and an octave downwards (=half frequency). The maximum frequency shift is around ±2kHz.
• The positions "5" - "5kHz" select the maximum frequency shift of ±5Hz, ±50Hz, ±500Hz and ±5kHz. Linear frequency shift means that the signal is downshifted upshifted by the same amount in Hertz. E.g at 1V at the CV input the signal is shifted 1kHz up- and downwards. All harmonic relationships will be eliminated that way.

After each change of scale you should re-adjust the point of zero shift with the "zero adjust" control. Remove all CVs, set the big knob to zero and fine tune "zero adjust" until the LED goes off.

If the input frequency is lower than the amount of shift in Hertz then the frequency will be "wrapped around" in best thru-zero-style and a positive frequency with negative phase will be produced.

Output A carries only the downshifted signal, output B carries only the upshifted signal. The three MIX outputs have the mixture of down- and upshifted signals and their relationship can be set with the MIX control.

Without input signal or at very low input levels the frequency shifter still produces side-noise that can be reduced with RS-240´s shiftable squelch circuitry which basically is a noise gate. If input level drops below the threshold (adjustable from 0dB to -60dB) the output signal will be gated.