BASTL Kastle Mini Modular Synth

Full Description

Digital Lo-Fi Sound

At the heart of the BASTL Kastle Mini Modular Synth is a highly compact modular synthesizer featuring 3 synthesis modes and versatile connectivity. The keystone of the Kastle combines complex oscillation and the LFO with a stepped waveform generator for a versatile sound palette. The oscillator section features 3 sound parameters with pitch, timbre and waveshape voltage control, accompanied by 3 different synthesis modes. The result is digitised lo-fi sounds, ideal for a wide range of genres and applications.

DIY Open Source Mini Synth

The synth was developed as an open-source DIY project that lets users expand on the factory configuration. At the heart of the BASTL Kastle Synth are two Attiny 85 chips, which can also reprogrammed using Arduino. Each chip is dedicated to a different role, with one chip dedicated to sound generation, while the other handles the modulation.

In-Depth Modulation

The 3 synthesis modes are comprised of phase distortion, phase modulation (FM) and track and hold modulation. Each mode uses both oscillators, with the pitch controlling the main oscillator and the Timbre setting the pitch of the modulating oscillator. The waveshape is dependent on the synthesis mode, with it controlling the pulse width of the square wave output form the main oscillator. The LFO is voltage controllable, featuring a triangle and square output, as well as a reset input. The stepped waveform generator was inspired by the Runbler circuit (by Rob Hordijk) providing 8 different voltage in random order or in 8 and 16 step looping patterns for optimal versatility.

Design & Construction

The highly compact design makes it ideal for musicians on the move, allowing you to create and edit sounds on the fly. The versatile design means you can edit the chips for endless possibilities. The robust yet highly portable design is ideal for live and studio applications alike. It features 2 I/O CV ports, which can be routed to any patch point for use with external equipment. The main output can also drive headphones for private listening. The Kastle Mini Synth itself runs on 3 x AA battery operation and features a convenient power switch. Additionally, the pattern on the side of the unit changes, making every unit original.

Features

• Complex oscillator with LFO
• 3 synthesis modes - phase distortion, phase modulation and track & hold modulation
• Pitch control with offset and CV input with attenuator
• Timbre control with offset and CV input with attenuator
• Waveshape control with offset and CV input
• Voltage controllable LFO with triangle and square outputs and reset input
• Stepped voltage generator with random, 8 step and loop 16 step mode
• 2 I/O CV ports are available and can be routed to any patch point
• Main output can drive headphones
• 3x AA battery operation with power switch
• Open source
• Possibility of exchanging different LFO and OSC chips
• The pattern on the sides changes and every unit is an original