Module A-114 contains two separate ring modulators. A ring modulator outputs the product (Multiplication X • Y) of the signals at inputs X and Y. It’s similar to a VCA, but whereas a VCA only responds to positive voltages at the inputs (2-quadrant multiplication), the ring modulator responds to both positive and negative voltages (4-quadrant multiplication).
The ring modulator thus provides a refinement of amplitude modulation (AM). Ordinary amplitude modulation will output the original carrier frequency fC as well as the two side bands (fC – fM, fC + fM) for each of the spectral components of the carrier and modulation signals – but ring modulation cancels out the carrier frequencies, and just lets the side-bands pass to the output (see Fig. 1).
A ring modulator is used for the production of bell-like sounds, alien voices, or just to produce new timbres.
User’s manual (English): A114_man.pdf
The module is suitable only for audio input levels (X In / Y In) up to 10Vpp. For higher levels clipping occurs. To avoid this attenuators may be used (e.g. A-183-1). Another possibility is to reduce the sensitivity of the inputs. For this the values of two resistors for each sub-unit have to be changed: R2/R2′ (100k) has to be reduced (e.g 82k or 75k), R3/R3′ (100k) has to be increased (e.g 120k or 150k). The positions can be found in the document A114_adjustment.pdf.
The inputs and outputs of the module are AC coupled. Consequently the module is suitable only for the processing of audio signals. A comparable module that is suitable also for slowly changing signals is A-133 Voltage Controlled Polarizer.
A module that contains only one ring modulator and instead of the second ring modulator a S&H/T&H/Slew Limiter is A-184-1.
Width: 4HP / 20.0 mm
Depth: 40 mm (measured from the rear side of the front panel)
Current: +40mA (+12V) / -30mA (-12V)