Matrix Mixer 4x4, DC Coupled, Active

DC coupled matrix mixer, PINAX
PINAX DC Coupled Matrix Mixer 4x4, for mixing Control Voltages & Audio
This is an active 4x4 Matrix Mixer with switches for unipolar/bipolar mode for each output column. The device's inputs & outputs are DC-coupled and can be used for Audio and Control Voltage mixing. The circuit is designed in such a way so that it actively rejects any kind of crosstalk among all inputs & outputs.
It is suitable for instruments (guitar, bass, etc), synths, eurorack signals and any kind of line level signals.

Unipolar mode: In this mode all pots feeding the respective output behave in regular fashion, that is when the knob is fully counter-clockwise, no signal from the associated input passes into the mix. As the knob is advanced clockwise, a greater portion of the signal passes into the mix. (At max position there is unity gain.)

Bipolar mode (phase reversal): In this mode, each knob has a zero position mid-way through it's travel. Turning the knob anti-clockwise will add an increasing portion of a negative (phase inverted) version of the signal at the corresponding input, while turning the knob clockwise will add an increasing portion of the original signal to the mix.

The mixer works with standard 9V pedal power supplies which internally is converted to dual rail supply (-15V,0,+15V) in order to achieve greater stability and maximum headroom for the ICs inside. 
NOTE: When mixing multiple audio and CV signals you have to take into consideration the level of each signal you route to the inputs and set each knob to the appropriate level in order to keep everything inside the headroom span and avoid distortion. The device can easily handle signals that are at line level or much higher but since all inputs are DC coupled extra attention is required when summing multiple signals from different sources.
TS 3.5mm inputs & outputs
▹ Input impedance: 1Mohm
▹ Output impedance: 330ohm
▹ Required power supply: 9V (polarity: negative tip)
▹ Available headroom: ~26Vpp (21.5dBu) AC
▹ Current Draw: 100mA
▹ Enclosure dimensions:  188 x 120 x 39 mm (7.40 x 4.72 x 1.53 in)
▹ Weight: ~750gr