Doepfer - A-138U: Dual Micro Mixer (2x3)
Module a-138u is a simple, low-cost mixer with two units. each unit is equipped with three inputs and one output. the upper unit has for each input a trimming potentiometer available that allows to adjust the amplification in the range 0...+1 for each input (factory setting is 1 for all inputs). the inputs of the lower unit all have the same amplification +1.
the output of the upper unit is normalled to the first input of the lower unit. that way the module can be used also as a mixer with five inputs: for this the inputs 1, 2 and 3 of the upper unit and the inputs 2 and 3 of the lower unit are used. the sum output for all five signals is then the output of the lower unit. as soon as a plug is inserted into input 1 of the lower unit the module becomes a dual 3-in-1 mixer again.
inputs and outputs are dc-coupled, i.e. audio and control signals can be mixed.
mixer for audio signals, e.g. three vcos preceding a vcf, when the amplifications are adjusted slightly different no signal extinction occurs during the beat of the vcos
mixer for control voltages (e.g. lfos, envelope generators, random voltages)
it requires 4 te/hp worth of space to fit in a eurorack frame.