Ostrawa from XAOC Devices is a voltage-controllable stereo mixer with four inputs. The module, which is fully equipped with a stereo signal path, is designed for performances and scores with studio-grade audio values thanks to high-quality op-amps in the VCAs and a low-distortion signal path. Each channel is equipped with a volume control, panorama control, muting switch (click-free), LED VU meter, Stereo inputs and control voltage inputs for Volume and panorama. The four inputs are summed via the stereo output. The stereo aux send/return enables the connection of a stereo effects module, the send levels can be individually adjusted for each channel. If the inputs are running low, Ostrawa provides a stereo direct input, which is passed through to the main output without any further adjustment options. By holding the mute button, you can define for each channel whether the aux send works pre- or post-VCA.

Ostrawa is a sister module to Praga. It has a very similar response and a similar arrangement of controls but has some functional differences resulting from the stereo inputs and the limited space on the control panel. Multiple Ostrawa and Praga Module can be daisy-chained for a customizable mixing system. The Bohumin expander, also available separately, complements Ostrawa with a second, fully-fledged aux send/return path and convenient CV/gate inputs.