A-138b Exponential Mixer

Doepfer's four channel mixer with logarithmic controls, made for mixing audio: each input has its own attenuator, and a master attenuator sets the output, so the mixer can end the audio chain and feed a mixing desk or an amplifier directly.

Key features

• Four inputs, each with its own level control (In1 to In4)
• An output level control (Out), unusual on an A-100 module
• Logarithmic potentiometers, for audio; the A-138a is the same mixer with linear ones, for control voltages
• With nothing plugged into Input 1, In1 gives a DC offset of about 0 to +5 V (an internal jumper)
• In aluminium or as the black Vintage Edition