Doepfer A-138n Narrow Mixer

Four-channel CV and audio mixer with master output

4 HP Eurorack module

The A-138 Mixer is a four-channel mixer for the Doepfer A-100 modular system, capable of handling both audio signals and control voltages. It features individual attenuators for each input plus a master output attenuator, giving it musical utility as both a sound blending tool and a CV summing node. Its two variants — linear for CV mixing and logarithmic for audio — make it a versatile utility module at the heart of any patch.

Features

• Four independent input channels each with attenuator knob
• Master output attenuator for end-of-chain level control
• Available in linear (A-138a) and logarithmic (A-138b) potentiometer variants
• Compatible with both audio signals and control voltages
• Optional DC offset function on Input 1 via internal jumper JP4 (modules from mid-2004)
• Positive or negative DC offset selectable via jumper position
• Can interface directly with external mixers, amplifiers, or mixing desks via master attenuator

Controls & Jacks (10)

• In 4— Attenuator for input 4 level control
• In 3— Attenuator for input 3 level control
• Input 3— Third input jack for audio or control voltage signals
• Input 1— First input jack for audio or control voltage signals
• In 2— Attenuator for input 2 level control
• In 1— Attenuator for input 1 level control
• Input 2— Second input jack for audio or control voltage signals
• Output— Mixed signal output jack
• Input 4— Fourth input jack for audio or control voltage signals
• Out— Output level attenuator for the mixed signal

How-To Guides

• Blend Two VCO Waveforms
• Sum ADSR and LFO for VCF Modulation
• Four-Voice Drum Bus Mix
• Keyboard CV with DC Offset Tuning
• Combine Four Modulation Sources for VCA
• Layered Drone from Multiple Oscillators
• Generative CV Soup from Random Sources
• Stereo Bus Interface to External Mixer

Explore the interactive A-138n Narrow Mixer panel on BleepDex — tap any control to learn what it does.