The Doepfer MS-404 is a MIDI-controlled monophonic analog synthesizer designed to be a rackmounted Roland TB-303 synth clone. It offers additional features, like MIDI and LFO’s, that give the synth additional flexibility.

The sound generating section of the MS-404 is 100% analog (VCO, Noise, VCF, VCA, ADSR, 2 LFO’s). Even the envelope and the LFO’s are pure analog and not simulated by software. Immediate access to all sound parameters is offered by 15 knobs and 6 switches. An external audio input enables sound mangling of other sound sources like samplers, digital synthesizers or expanders.

On top of that the MS-404 works as a monophonic MIDI-to-CV interface to control another analog synthesizer. The MS-404 is capable of controlling VCF frequency and VCA envelope amount (accent) via MIDI.

If you’ve used the Doepfer MS-404 MIDI bassline synthesizer, leave a comment with your thoughts.

MS-404 Features

VCO

• real VCO (no DCO)
• switchable between sawtooth / off / rectangle (pulse)
• pulsewidth of rectangle adjustable, pulsewidth modulation with LFO1
• glide time adjustable, glide on/off via MIDI-Controller #65 (Portamento)
• frequency modulation with LFO1, even in audio range for producing typical FM sounds

NOISE

• white noise as alternative sound source (switcheable instead of VCO)

VCF

• 24dB resonance filter (low pass), resonance/emphasis adjustable up to self oscillation
• frequency may be controlled via any MIDI controller and/or MIDI velocity
• frequency modulation with LFO2, even in audio range for metallic/FM sounds
• keyboard tracking switchable off/half/full

VCA

• envelope amount (accent) controllable via MIDI volume (ctr.#7) and/or velocity
• effect of accent adjustable (accent knob)
• full ADSR type (Attack-Decay-Sustain-Release)

LFO1 and LFO2

• 3 frequency ranges from sub-LFO (some minutes oscillation period) up to audio (max. 5kHz)
• waveform triangle
• frequency and level adjustable
• LFO1: to VCO frequency or VCO pulsewidth modulation switchable
• LFO2: VCF frequency

External Audio Input

• level adjustable
• alternative sound source instead of VCO or Noise

MIDI-CV Interface (internal):

• MIDI channel and transpose (reference note) selectable via learn button
• retrigger on/off (new trigger if playing legato)
• controlling of glide on/off via Controller #65
• controlling of VCF frequency via any Controller and/or Velocity
• controlling of VCA envelope amount via Controller #7 and/or velocity
• two 1/4″ jack sockets for CV und Gate Output (may be changed to CV/Gate Input when changing jumpers inside by authorized dealers)
• light grey 19″ housing, 1 unit

Resources:

• The Doepfer MS-404 official page
• Video via jkselsyn