Xaoc Devices Praga

1967 Voltage Controlled Mixing Console

Praga is a voltage controlled four channer stereo mixer. Each channel features:

manual and voltage control over volume and panning
indivual VCA outs
2 auxilliary sends
mode switch for envelope or LFO operation (attenuators change function, being and offset, or CV amount controls, respectively)
channel muting
5-bar signal level indicator
The module is build around high quality VCA chips from THAT Corp, as well as low noise opamps. It offers clickless muting and equal loudness panning. The distinct feature is that voltage control is dynamically compressed should it yield clipping when pushed too hard. Also, in both modes the attenuators offer full closing of the corresponding channel, regardless of being controlled by the CV, or not. The VCAs fully open (0dB gain) at CV=8V in Env mode and CV=5V in LFO mode. All the input and output signal levels are Eurorack levels.

Multiple Praga units can be chained thanks to dedicated headers on the back. The mixed stereo sum of each unit in the chain is added to the mixing bus of all units downstream.

A dedicated Hrad expander will offer master volume control, gate inputs for channels muting/unmuting, headphone amplifier, and voltage control over aux sends.

DESCRIPTION
Praga is an expandable four-channel voltage controlled mixer featuring a stereo mixing bus, two auxiliary sends with stereo returns, clickless muting, dedicated modes for unipolar and bipolar voltage control over volume, DC-coupling, and a super-clean signal path obtained via high-quality VCA and opamp chips.

We have carefully crafted Praga’s voltage control response to achieve what we believe to be the optimal user experience found in an eurorack mixer. The design features an elaborate control circuit that combines the internal voltages generated by the panel potentiometers with external CV over volume and pan. The result is a natural attenuator response that constrains VCA gain to an usable range while minimizing distortion.

For detailed description, please refer to the manual.

FEATURES
Intuitive volume control behaviour
Voltage control over volume and pan
Dedicated modes for unipolar and bipolar voltage control over volume
DC-coupled signal path
Channel level indicators
Two auxiliary sends with stereo returns
Clickless channel muting
TECHNICAL DETAILS
Eurorack synth compatible
20hp, skiff friendly
Current draw: +210mA / -180mA
Reverse power protection
EXPANDABILITY
Expandable by daisy-chaining more units
A dedicated Hrad expander module is planned