Doepfer - A-138b Mixer Logarithmic (Silver)

The Doepfer A-138b is a classic 4-channel logarithmic mixer designed primarily for blending audio signals within your Eurorack system. Its exponential response curve makes it especially suitable for summing audio with natural-sounding level control.

Each of the four inputs includes a dedicated level knob. While it’s optimised for audio, the A-138b can also mix control voltages—though the logarithmic taper of the pots may produce non-linear CV behaviour.

A handy bonus: if nothing is patched into input 1, channel 1’s control becomes an offset generator. A jumper on the PCB allows you to select whether this offset ranges from -5V to 0V or from 0V to +5V.

• 4-channel logarithmic audio mixer

• Designed for natural audio-level blending

• Also usable with CVs (with non-linear behaviour)

• Channel 1 can act as offset generator

• Offset range jumper-selectable (-5V to 0V or 0V to +5V)

• Width: 8HP