Each input pair consists of a carrier and a modulation signal input. Their combination is symbolized with the X in a circle on the front panel. The purpose of this module is to modulate a carrier signal with a modulation signal.
One input pair of each ringmodulator has an adjustable pre-amplifier per channel to be able to process microphone or guitar signals.
The combination signal of the carrier and input signal contains the sum and the difference of the input voltages / signals and is only provided if both carrier and input signals are present.
The musical effect of this module is new spectrum of harmonics in the output signal; depending on freuqency differences between the two input signals the output signal sounds more 'fat' or more metallic. Two ringmodulated sinus signals detuned by seven or eight semitones lowpassed by a VCF make a nice bell sound.
Schematic:
The schema is part of the book "Formant Pro MSS 2000" by H.J. Helmstedt.
Sound example:
Example 1: Greetings from Big Ben: Two sinus signals, detuned by ca. eight semitones, the ringmodulated signal lowpassed a filter.
Example 2: Chinese ghosts: A sinus signal is ringmodulated by a VLF signal from the noise module.
Example 3: China once again: Two square signals, detuned by ca. eight semitones, the ringmodulated signal also lowpassed a filter.
Reproduction hints:
I made a new layout to get three ringmodulators on one eurocard.
The final adjustment of one ringmodulator caused problems, the others worked fine. I think this is due to tolerances in chip manufaction of the MC1496, but I have to check it.