Plankton Electronics Releases The Earwig Rectifying Mixer Eurorack Module

via Plankton Electronics

"The Earwig is a rectifying mixer. The core of each channel are two half wave rectifiers and one full wave rectifier. There is also gain, pre and post-rectifier bias and an inverter amp. 2 CV bias inputs are provided to modulate the signal. Each channel accepts audio and CV signals. Available at the store as a modular kit or fully assembled.

HOW IT WORKS

The input signal passes through a first stage of gain and bias. This stage is used to shape the signal at the next stage, the rectifier. The bias input is very useful to modulate the signal here and create changing patterns after the rectifier. The rectifier has 4 positions: bypass, positive wave inverted, negative wave inverted & full wave inverted. With the positive wave inverted position only the signal that stays above 0 volts passes to the other side. The result is inverted. At the 3rd position, only the negative signal, everything below 0, passes through. And again it’s inverted. At the last position the positive voltage keeps the same, and the negative is inverted, so if we input a sine wave the result is an “m” shaped wave. The result is inverted again.

After this stage there is an inverter switch, so we can keep the signal as it is or invert it.

Finally we have another bias stage. This stage let’s us to move the rectified signal again to the 0 point and modulate it. The channel output is connected here directly.

The mix pots attenuates the signal and mix it between the 2 channels, summing and subtracting the 2 channels.

It’s important to understand that the module is not AC coupled. This means that it works for audio and CV signals. So when an audio signal is rectified it will be centered in the 0V range. The second bias potentiometer is useful for achieve this.

When connecting a signal to the “BIAS” inputs it is useful to attenuate it previously to avoid saturating the amp. the module does not have attenuators."