River Creative – Crux – Full DIY Kit

£119.00 (Excl. VAT)

Dual VCA with discrete OTA core

In stock

SKU: Kit_River_Crux Categories: , , Brand:


The Crux contains two independent VCAs, built around discrete transistor OTA circuits, in a compact 6HP Eurorack module. The VCA circuits are designed for input levels of 10Vpp (peak to peak) and will start to gently saturate beyond these levels up to the clipping level of 20Vpp. They feature linear and exponential response curves, as well as modes for treating audio (AC) and CV (DC) signals.

Each VCA can be controlled via two CV inputs, one of which is intended for unipolar signals (ENV: e.g. envelope CVs; in the range of 0 to +5V), while the other is intended for bipolar modulation (MOD: e.g. LFOs; in the range of -5 to +5V). When the ENV input is not used, it normalizes to +2.5V, which gives full range VCA control to the MOD input. The VCAs were designed for a warm and vivid sound character, courtesy of the discrete OTAs, this also means: look elsewhere if you are in need of super-accurate and ultra-clean VCAs.

Build Document | User Manual


  • Dual VCA around discrete transistor OTA core
  • Switchable linear or exponential VCA response
  • Switchable between Audio (AC) and CV (DC) use
  • Starts to pleasantly saturate beyond levels of 10Vpp (clips at 20Vpp)
  • Envelope (unipolar) and modulation (bipolar) CV inputs
  • Smart normalization of unused envelope inputs to allow for full-range bipolar modulation
  • All SMD pre-soldered
  • Width: 6HP
  • Depth: 32mm
  • Consumption: 23mA @ +12V, 23mA @ -12V

Additional information

Weight 0.0641 kg
HP Size

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