tanh[3] is a three channel, all analogue, wave shaper. It takes an input signal and outputs the hyperbolic tangent function [tanh (x)] for that signal.

…In more useful terms, it adds curves to a signal!

Traditionally the circuit is used to shape a triangle wave to a sine but when used with more complex signals it behaves as a single knob limiter.

Available now! (Built in small batches, contact for lead time)

For any Max/MSP and/or Pd users, the [tanh~] object may be familiar.

And to those who are familiar with it, it is likely a much used secret weapon in many contexts!


Describing what the tanh does to a signal, both mathematically and sonically can be a headache, and not particularly useful. So I will describe some particularly fun use cases to give a bit of context.


Feedback control:

Feedback is fun. But feedback can get unpredictable, and explode!

Whether it’s feedback in a delay loop, a reverb, filter or straight up microphonic, a tanh can be inserted in the feedback path and used to reign in runaway oscillations.

In this context it functions as a limiter on feedback amplitude.

Instead of fading away to silence, when longer sustain is desired, or running away uncontrollably, a signal can be controlled much more easily with a tanh. There will be a much wider range at which a feedback oscillation will stabilise musically.


Wave shaping:

Running a triangle wave through a tanh will allow for some interesting wave shaping control.

Fully CCW and the resulting signal will be a slightly attenuated pass through of the original triangle wave. As the level is increased, the corners will soften and the wave form will shape into a sine wave.

As level is increased, the sine will soft clip and eventually settle into a unique peaked waveform.



Running any complex audio signal through a tanh channel is highly recommended. Drum voices especially!

The effect is sonically similar to compression, but achieved through complex wave shaping as opposed to gain reduction. Limiting is a more appropriate description but it definitely has its own unique characteristic.

Increasing the level will introduce soft clipping distortion/overdrive.



+12V: 20mA

–12V: 15mA

Depth: 27mm

  • Three independent channels of tanh wave shaping