RK1 Noisedrum


Out of stock

SKU: MET_RK1 Maker: Types: , ,


The RK1 is intended to serve as a “cymbal” or “snare” sound for synthesis of electronic drums. Or as a conventional noise source. The use of vacuum-tube technology and a specially-chosen noise diode running at a high breakdown voltage insures that the RK1 gives a powerful, ass-kicking, crispy-crunchy sound.

It will punch you in the face. It will utterly crush the wimpy “606 cymbal” sounds produced by other solid-state drum sound modules or “vintage” analog drum machines.

A special selected noise diode generates the white noise, and a vacuum-tube pentode to amplify and gate the noise on and off. A built-in envelope generator allows adjustment of the attack and decay time. Long attack times will require triggering with a long positive pulse, while “typical” cymbal sounds with adjustable decay can be made with a short trigger pulse. A trigger of at least +5 volts is recommended for best performance. A built-in high-cut filter allows adjustment of the noise sound from full-range to a rolloff of about 100 Hz, giving a unique “thunk” tone.

Video of an RK1 in action

Trigger and CV inputs have 100k ohm impedance. The maximum audio output is “hot” (up to +10 dBu) and able to drive a 600-ohm load. The CV input affects the DECAY time, and may be anywhere in the -10v to +10v range – the effective range is +1.5v to +5v. 6CB6 or 6CF6 pentodes will work and are extremely commonplace and easy to get. 6AU6, 6AK5 or compatible types will also work.

Power requirement: +12v dc, 200 mA and -12v, 10 mA. As with all our modules, it draws about 2.5 times the operating current during “cold” power-up, and you must insure your power supply can handle the inrush current. See our support section for more information and power supply suggestions.

The Metasonix RK-series of vacuum-tube modules is intended for use in any “Eurorack” standard modular synthesizer system. All RK-series modules are 8HP (40.7mm) wide and fit in any Doepfer(tm), Analogue Systems(tm), or other compatible cabinet. They are powered entirely from the cabinet’s internal +-12v dc power supplies, using Doepfer compatible 16-pin power connectors. Their circuits protrude behind the panel less than 31mm (1.2 inch). All vacuum tubes are NOS (new old stock) types from classic American and European manufacturers that are run very conservatively for long life, and are readily available from distributors. The 6CB6 tube protrudes from the panel for visibility and cooling, less than 40mm (1.58 inches), and will fit inside a Doepfer A-100 suitcase cabinet lid or into a Doepfer mini case or Monorocket case cover. All audio inputs and outputs and CV inputs/outputs are 100% compatible with other synthesizer modules. Plate voltage is provided by a tiny switching supply producing clean 48v regulated at low current, which is very safe and will not injure the user. Potentiometers are top-quality Alpha RK12L types, and 3.5mm phone jacks are special Kobiconn vertical-mount types, much better quality than the cheap ones usually seen in Euro modules. Each RK-module is fully protected against reverse supply voltage, overvoltage, undervoltage, or incorrect hookup to external equipment. So stop worrying!


  • Handcrafted in Northern California, USA
  • +/-12V Doepfer-style power connector
  • Power: +12v dc, 200 mA and -12v, 10 mA.
  • Panel width: 8HP