Kastle Drum

Bastl Instruments
Have you ever wondered how to generate rhythms on a patchable drum machine that has neither buttons, nor a programmable sequencer? You use a Bastl Kastle Drum!

The Kastle Drum is a special edition of Bastl’s classic mini modular synth focusing on algorithmic industrial glitchy drums.

Drum sound synthesis with a unique dynamic acceleration charged envelope makes this rhythm box surprisingly versatile and extremely fun to play. The built-in VC clock generator with a stepped pattern sequencer can either run on its own or it can be synchronized to analog clock, while retaining the triangle LFO for parameter modulation.

The Kastle Drum is a mini modular synthesizer with a headphone output, 2 in/out ports for interfacing other gear, and it runs on just 3 AA batteries. It is ideal for beginners in modular synthesis, but it will add some quite unique functionality to any modular synthesizer system. It delivers the fun of modular synthesis at a low price and fits into your pocket so you can play it anywhere!


  • 8 drum synthesis styles

  • ”Noises” output for less tonal content

  • DRUM selects drum sounds

  • Acceleration charge dynamic envelopedecay time

  • PITCH control with offset and CV input with attenuatorvoltage-controllable clock with square and triangle output

  • Stepped voltage generator with random, 8 step and 16 step loop mode

  • 2 I/O CV ports that can be routed to any patch point

  • Main output can drive headphones

  • 3x AA battery operation or USB power selectable by a switch

  • Open Source!

  • Durable black & gold PCB enclosure