Quite noisy module because of low power TL-064 used for amplifiyng the signal. But this can be improved with any quality OpAmp having same pin-out. I've tried OP470, but it's very expensive IC.
Module A-138 is a four channel mixer, which can be used with either control voltages or audio signals. Each of the four inputs has an attenuator, and there's a master attenuator, so that the mixer can be used at the end of the audio chain - ie. it can be used to interface directly with an external mixer, amplifier, etc.
The module can be supplied in two versions:
A-138 a: potentiometers with linear response, so especially suitable for control voltage mixing.
A-138 b: potentiometers with logarithmic response, so especially suitable for audio signal mixing.
For more detailed information please look at the English user's manual: http://www.doepfer.de/a100man/a138man.pdf
This module is currently available.$80 submitted Oct 6th 2012, 13:36 by gogoolplex | last Change Sep 29th 2016, 17:45 by modulargrid