Doepfer A-119 Ext. Input / Envelope Follower
Turn any external audio into modular control voltage
8 HP Eurorack module
The A-119 External Input / Envelope Follower brings outside audio signals into the Doepfer A-100 modular system via a preamp with both balanced and unbalanced inputs. It extracts a smooth envelope voltage from the incoming signal and generates gate pulses whenever that envelope crosses an adjustable threshold, enabling the dynamics and rhythm of any external sound source to directly control synthesizer parameters. Its musical character is reactive and expressive, turning vocals, guitars, drums, or any acoustic source into a living control voltage.
Features
- Unbalanced 3.5 mm mono jack input (Asym. In) for line-level signals with gain range 0 to 20
- Balanced 6.3 mm stereo full-size jack input (Symm. In) for low-level sources such as microphone or electric guitar with gain range 0 to 500
- Single Gain knob controls amplification for whichever input is in use
- Amplified audio available at two linked Audio Out sockets acting as a mini-multiple
- Full-wave rectifier converts amplified signal to positive-only voltages for envelope detection
- 50 Hz low-pass filter smooths rectified signal into envelope CV at Env. Out
- Adjustable Threshold knob sets comparator trigger level for gate generation
- Gate Out produces gate signal whenever envelope exceeds the trigger threshold
- Overload LED warns when amplified signal exceeds 10 V
- Envelope LED monitors voltage level at Env. Out
- Gate LED monitors gate signal at Gate Out
- If both inputs are used simultaneously, signals are mixed in a 1:25 ratio
Controls & Jacks (9)
- Asym. In
- Symm. In
- Audio Out
- Gain
- Envelope Out
- Overload LED
- Envelope LED
- Gate Out
- Threshold
How-To Guides
- Bringing a Line-Level Source Into the System
- Using a Microphone or Guitar as a CV Source
- Filtering External Audio with ADSR-Controlled VCF
- Ring Modulator Squelch Patch
- Ducking an A-100 Sound with External Audio
- Singing Synth with Sub-Octave Harmonics
- Envelope Follower as Dynamic VCA Controller
- Extracting Rhythmic Gates from a Drum Loop
- Envelope Follower Controlling Pitch
- Smooth Envelope Follower for Low-Frequency Sources
Explore the interactive A-119 Ext. Input / Envelope Follower panel on BleepDex — tap any control to learn what it does.
