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Bastl Instruments - Midilooper

Midilooper - Flex your muscles with speedy, open-ended MIDI looping

Looping is one of the fastest and most intuitive ways of music-making. It's always been great for improv and invention, but why not try it with MIDI messages this time?

The Bastl Midilooper is an experimental device that will help you do just that. It listens to control information about notes, dynamics, and other parameters, and it loops them in a way an audio looper would process pieces of audio. Since the MIDI loops remain in the control domain, many other processes can happen simultaneously on top of them - so you can explore timbre modulation, envelope adjustments, and way more.

We designed the controls of the Midilooper to be easy to access so that the device comes in handy and enhances your music-making flow. Your fresh ideas are just a few button presses away: “[The Midilooper is] highly recommended if you’re trying to simplify your workflow and/or get away from menu-diving outside of the computer,” says a recent review in The Waveform Magazine, and we couldn’t agree more. Here is a video


Plug & Play

The device fits into any playful production workflow, and it can be synchronized with other gear like synths and controllers either by MIDI clock or analog clock, or it can also run on its own clock (tap tempo/free running).

The Midilooper offers 3 voices that can each be assigned to a different MIDI channel, allowing it to control 3 other devices. Each voice can be individually recorded, muted, overdubbed, or cleared as you go.

The Midilooper also offers some basic processing of the recorded information: transposition, velocity locking and shifting, quantization, shuffle, humanization (random variations of velocity), adjusting the length of the loop, or doubling and halving of the playback speed.

In addition, it features CV and trigger inputs to integrate with modular synthesizers so you can reset, re-trigger, manipulate velocity, and transpose. It can also be controlled by connecting a foot pedal.



• 3 independent voices (each has MIDI channel assigned)

• overdub/overwrite

• transpose mode

• octave transpose

• quantize, velocity lock, shuffle, humanize

• odd looplengths, time stretch

• mute, clear, erase

• one MIDI Input and two MIDI Outputs

• clock input (accepts analog clock or TRS MIDI Clock)

• analog reset input

• metronome output

• CV input connectivity (transpose, velocity, re-trigger)

• pedal control (record, clear, voice selection)

• USB powered

• adjustable divider/multiplier for the analog clock

• dimensions: 125mm x 80mm x 35 mm


Download the latest firmware here and the manual here.

Bastl Instruments - Midilooper
295,00 €

250,75 €

  • 0,45 kg
  • Available
  • Ships within 3-5 days1

Bastl Instruments - Kastle Drum

Kastle Drum - Discover Rhythm on a tiny patchable Groovebox

Have you ever wondered how to generate rhythm on a patchable drum machine that has neither buttons, nor a programmable sequencer? We have and turns out you gotta discover it! Kastle was originally released in Fall 2016 and gained instant popularity as an affordable, pocket-sized modular synth. We processed a lot of feedback and introduced a much improved version v1.5 a year later. Now we’re revisiting the concept once again with an alternative way to operate the same hardware.


The design process gave birth to a seemingly limited, but in fact an innovative and quite playful take on a rhythm box that is using some novel concepts, like the dynamic acceleration envelope to build “a lot of dynamic rhythm” out of very little modulation.


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!


Kastle is an open source project with all resources obtainable from GitHub. Given that anyone can do anything with the code, we cannot provide any support for user upgrades from Kastle v1.5. All information is easy to find online for curious users, but please understand that we do not have the capacity to help you with that process.



• 8 drum synthesis styles

• ”noises” output for less tonal content

• DRUM selects drum sounds

• acceleration charge dynamic envelope

• decay time

• PITCH control with offset and CV input with attenuator

• voltage-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

• the main output can drive headphones

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

• open source

• durable black & gold PCB enclosure


Technical details

• dimensions: 70 x 60 x 50 mm

• powered by 3x AA battery or Micro USB


What’s in the box

• Kastle synthesizer

• 10 patch cables

• sticker

• batteries not included


Download the latest firmware here and the manual here.

Bastl Instruments - Kastle Drum
107,00 €

90,95 €

  • 0,3 kg
  • Available
  • Ships within 3-5 days1