Ring Modulator
A transformerless diode ring modulator. The summing and subtracting of the carrier and modulation signal are done using opamps, with a differential amplifier reading the diode ring output. I found that the it sounds slightly better using a sinusoidal carrier, for which the Wien Bridge Oscillator circuit could be used. Alternatively, a relaxation oscillator could be used for simplicity. Note that the “carrier null” circuit is not included. A variable gain amplifier/attenuator for the carrier signal should do the job.
