Cryfder

Dual diode-based VCA with VFD mixer/distortion

Cryfder ('strength' in the Welsh language) is a dual diode-based voltage-controlled amplifier for Eurorack modular systems, with a small but mighty real vacuum fluorescent triode as a mixer, overdrive, distortion and feedback loop creator. It is intended to be a flexible building block with plenty of character.

Each VCA has attenuverters on CV inputs, DC offset control and an input gain knob that lets you drive the VCA core into triangle-to-sine style soft clipping. Both the audio in and CV in of VCA 1 are normalled to VCA 2, allowing for flexible configuration as a stereo VCA, voltage-controlled panner or crossfader, and much more.

The VFD triode used in Cryfder was developed in the 1950s as an indicator lamp for early computer front panels, but has been transformed into a genuine directly heated thermionic amplifier stage. Adjustable positive feedback around the VFD allows for overdrive, distortion, fuzz and eventually full self-oscillation.

Buy Cryfder from the Dwyfor Tech stores on Reverb or Etsy.
Read the build/user manual and more in the documentation.