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μsum / moog cp3 based 3-channel analog mixer with eq & mute switches / 8 HP

μSUM is the successor of KNEAD and has an improved circuitry and PCB layout. It was inspired by the famous MOOG CP3-Type Mixer. The circuit adds some nice harmonic distortion to the signal with heavy clipping, if the inputs are turned to the maximum. As the mix is bussed passively turning one input up may result in a reduction of the other inputs. Therefore the output cannot exceed any other input´s level providing auto-leveling on high volumes.

key features

  • CP3 Transistor-Based Analog Mixer

  • 3 Audio Channels

  • 3x EQ

  • 3x Mute Switch

  • 3x Signal LEDs

  • MIX Volume

  • Skiff friendly

  • Wrong polarity protection

specs & downloads

  • width: 8 HP

  • depth: 30 mm

  • power: 56 mA @ +12V / 45 mA @ -12V


description / manual

There are three potentiometers to adjust the LEVEL for each signal. Additionally you may change the frequencies of each channel by turning the EQ knobs. EQ will boost high frequencies turning the knob clockwise and boost low frequencies turning it counter-clockwise. On top you will find MUTE switches for easy sound comparison or live mixing. LEDs will indicate if a signal is passed through. The LED´s brightness can be set with trim potentiometers for each channel. The MIX VOL knob controls the volume of the summed signal being supplied at the OUT Jack.

Knead Expander has been omitted on the μSUM Mixer.