Mezclador para señales de audio

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. 

A-138b: potentiometers with logarithmic response, so especially suitable for audio signal mixing.