The Marconi Musical Modulator

Built for Daniel GlatzelAndromeda Mega Express Orchestra

The Maconi Musical Modulator is a tube ring modulator effect unit built from an old defective Marconi universal bridge measuring device. When Daniel first expressed interest in an effects unit, we talked about many different possibilities: from a wah wah, to a reverb unit, and so on. However, what he really wanted was something that was very distinctive and prominent, hence we decided on a ring modulator.

Normally seen as unmusical and rather harsh, this unit is anything but. First off, the signal goes through a simple transformer, then a vintage Germanium bridge rectifier and back through another transformer. This is the classic method of a passive ring modulator. The signal is then amplified by a single triode and mixed with the “dry” signal. The dry signal actually is able to be effected as well while a gain, mids and tone control are all available.

The carrier section includes a multi-waveform (square, triangle or sine) inbuilt oscillator. A frequency range control on the large dial allows for a frequency from 10Hz to 1MHz in ten switchable steps– the pot in the middle allows the user to sweep this frequency. With a multi-turn null pot (here labelled “Sensitivity”) and perfectly matched diodes, carrier bleed-through is non-existent. The black jack input accepts an external carrier signal.

Check out the unit in action by seeing the Andromeda Mega Express Orchestra!