The Kastle can operate alone or with another tiny synth or drum machine.

Boutique Czech synth company Bastl Instruments has unveiled its latest device, a tiny modular synth that’s the size of the three AA batteries that power it.

The Kastle costs just €65, and is billed by Bastl Instruments as being ideal for newcomers to modular synthesis, but should also be useful to those who already have an existing Eurorack system. It can also be hooked up to other small synths, such as Teenage Engineering’s Pocket Operators and Korg’s Volca series.

The open-source device has a lo-fi digital sound that lends itself to soft or harsh tones. It runs off two chips that can be reprogrammed with an Arduino, allowing coders to change the synths’ sound generation and modulation parameters.

Pitch, timbre, wave shape and LFO can all be patched using the 10 tiny cables included in the box, while those with a larger modular system can connect the Kastle via two I/O CV outputs at the rear of the device.

The Kastle is the latest in a long line of unique products from the Czech company, whose products range from handmade wooden synth modules, to a tiny sampler called the Microgranny.


Read next: The 13 best affordable, pocket-sized, hackable, off-the-wall synthesizers



Share Tweet

Privacy Preference Center

Required Cookies & Technologies

Some of the technologies we use are necessary for critical functions like security and site integrity, account authentication, security and privacy preferences, internal site usage and maintenance data, and to make the site work correctly for browsing and transactions.

gdpr, woocommerce_cart_hash, woocommerce_items_in_cart, _wp_wocommerce_session, sucuri_cloudproxy_uuid_*

Site Customisation

Cookies and similar technologies are used to improve your experience, to do things like:

- remember your login, general, and regional preferences
- personalize content, search, recommendations, and offers

Without these technologies, things like personalised recommendations, your account preferences, or localisation may not work correctly.


Personalised Advertising

These technologies are used for things like:

- personalised ads
- to limit how many times you see an ad
- to understand usage via Google Analytics
- to understand how you got to our web properties
- to ensure that we understand the audience and can provide relevant ads

We do this with social media, marketing, and analytics partners (who may have their own information they’ve collected). Saying no will not stop you from seeing our ads, but it may make them less relevant or more repetitive.

_ga, _gid, gat,_gads,_fbp