Bastl Instruments has released firmware version 1.7 for its Kastle 2 series, a family of small, patchable, battery-powered modular synths. In addition, the company is offering alternative open-source engines that users can load onto the hardware to explore new sounds and functions.

What the Kastle 2 Offers

The Kastle 2 is a compact modular instrument that can act as a synthesizer or an effects unit, depending on which firmware is loaded. Its patchable design and battery operation make it a portable option for sound experimentation. Because the platform is open source, users can dig into the code, modify engines, or create their own.

Firmware 1.7 and Alternative Engines

Version 1.7 brings updates to the existing Kastle 2 firmware. Alongside the official release, Bastl points users toward a selection of alternative engines. These community-driven engines expand the synth’s sonic range and add new functionality, from different synthesis approaches to alternative effects processing. As a result, a single Kastle 2 unit can be reconfigured into several distinct instruments.

Open Source Philosophy

Bastl has long emphasized openness. Most of its schematics and code are published for hacking and modding, and the Kastle platform, including the Eurorack-format CITADEL extension, has been open-sourced as well. This approach encourages a DIY community around the hardware, which is why alternative engines keep appearing for the Kastle series.

Availability

Firmware 1.7 is a free update for existing Kastle 2 owners and can be downloaded from Bastl Instruments’ website. The alternative engines are also freely available, giving current users new reasons to revisit their hardware without any additional cost.

More info: Bastl Instruments | Kastle 2 Firmware 1.7