The Nebensprechdämpfung Tube Ring Modulator

Built for John Gürtler
The Nebensprechdämpfung (Crosstalk sttenuation) Tube Ring Modulator is a project that I have wanted to make for a long time, and sometimes the right case and customer come along to finish it.  Originally conceived as having tube diodes as well, I had to give up on this route as it was too difficult to find matching diodes in the same tube.  In the end, I had a number of vintage germaniums that tested out perfectly as well as sounding great.
The circuit uses a passive ring modulator followed by a tube gain stage mixed in parallel with a clean tube gain stage.  There are individual gain levels for each as well as a master volume and tone control.  The built-in oscillator has two waveforms: triangle and square which allows for different modulation of the signal.  One of the many quirks of the unit is the fact that the square wave oscillator creates a tremolo effect at very low frequencies! As well, an exterior carrier can be used to effect the ring modulator.
All-in-all, the case makes for a portable unit that can be used easily live.  In the works is another, high-end unit that will be of studio quality.
Price for this unit starts at €350