The Dreadbox Erebus is a compact, affordable analog synthesizer that punches well above its weight class. This distinctive desktop synth represents Dreadbox's evolution from boutique pedal manufacturing into the synthesizer realm. Named after the Greek primordial god of darkness, the Erebus brings a unique character to the crowded small-format analog synth market.

Housed in a rugged metal enclosure painted in grey and fluorescent green with wooden edges, the Erebus presents a substantial presence despite its compact footprint. The build quality is immediately apparent through its high-quality knobs of varying sizes, with the larger ones reserved for critical functions like VCO tuning, filter cutoff, and output level. The tactile experience is enhanced by weighty knobs that resist accidental movement while providing precise control.

What sets the Erebus apart from its competitors is its duophonic capability - making it one of the most affordable two-voice analog synthesizers available. The instrument features two VCOs with different waveform options: VCO1 offers sawtooth and square waves across 8', 16', and 32' ranges, while VCO2 provides sawtooth and triangle waves pitched an octave higher. Each oscillator has independent glide controls, allowing for creative voice separation in duophonic mode.

The synthesis architecture centers around a characterful two-pole filter that delivers a fat, dark, and mildly aggressive tone. Even at minimum resonance, the filter maintains a residual resonance that creates a richer, thicker tonality than typical 12dB/octave designs. The filter is served by a full ADSR envelope with single or multiple triggering modes, while a separate AR envelope handles the amplifier stage.

A standout feature is the built-in digital delay unit with analog-style pitch swoops when adjusting delay time. With approximately 700ms maximum delay time, it excels at creating reverb-tank impersonations, spring reverb effects, and chorus-like textures at shorter settings. At high feedback levels, it transforms into a source of chaotic self-oscillation perfect for sound design.

The comprehensive CV patchbay is intelligently positioned to avoid interference with regular operation while providing extensive modulation possibilities. With nine inputs and six outputs, plus mini-knobs for attenuating modulation sources, the patchbay transforms the Erebus from a simple synth into a semi-modular powerhouse that plays well with Eurorack systems and other CV-equipped gear.

The slow-cycling LFO, capable of nearly two-minute cycles at its slowest setting, makes the Erebus particularly suited to psychedelic and ambient applications. Combined with the duophonic capability and characterful filter, it excels at creating evolving soundscapes, monster bass lines, and cosmic sound effects.

While the Erebus has some limitations - no velocity response, basic MIDI implementation, and the need for a screwdriver to change MIDI channels - its strengths far outweigh these minor inconveniences. It's a synthesizer that rewards exploration and patching experimentation, offering a warm, musical sound that cuts through mixes with authority.

Technical Specifications

Oscillators

• VCO Count: 2 analog voltage-controlled oscillators
• VCO1 Waveforms: Sawtooth, Square (optional)
• VCO2 Waveforms: Sawtooth, Triangle
• VCO1 Range: 8', 16', 32'
• VCO2 Range: One octave higher than VCO1
• Tuning Range: ±5 semitones up, 9 semitones down (VCO2 offset)
• Glide: Independent glide controls for each VCO
• Stability Time: 5-20 minutes warm-up period

Filter

• Type: Two-pole analog filter (12dB/octave)
• Character: Fat, dark, mildly aggressive with residual resonance
• Envelope: Full ADSR with single/multiple triggering modes
• CV Input: Voltage-controllable cutoff frequency

Envelopes

• Filter Envelope: ADSR with negative sustain capability
• Amplifier Envelope: AR (Attack/Release) type
• Maximum Release: Approximately 10 seconds

LFO

• Waveforms: Triangle, Square
• Rate Range: 0.009Hz to 30Hz (up to 2-minute cycles)
• Free-running: Yes, with visual LED indicator

Effects

• Delay Type: Digital with analog-style pitch swoops
• Maximum Delay Time: ~700ms
• Controls: Time, Feedback, Mix
• Character: Distortion above 350-400ms, capable of self-oscillation

Polyphony & Modes

• Duophonic Mode: Lowest note → VCO1, next lowest → VCO2
• Unison Mode: Both oscillators play same note
• Voice Allocation: Automatic note assignment in duophonic mode

CV Patchbay

• Inputs (9): VCO1 Freq, VCO2 Freq, CV (both VCOs), VCF, Echo Time, Gate, LFO Rate, LFO Depth, Resonance
• Outputs (6): Mod (MIDI mod wheel), Gate, Env, CV1, CV2, LFO
• Attenuators: Mini-knobs for Mod and Env outputs
• Connector Type: 3.5mm mini-jacks

MIDI Implementation

• MIDI Channels: 2-7 or Omni mode (set via internal DIP switches)
• Note Range: 5 octaves
• Velocity: Not supported
• Mod Wheel: Extracted and available at patchbay
• Connectors: MIDI In, MIDI Thru

Audio I/O

• Main Output: 1/4" jack (line level)
• External Input: 1/4" jack (processes through filter and delay)
• CV/Gate Input: 1V/Oct standard

Additional Features

• External Audio Processing: Route external signals through filter and delay
• MIDI-to-CV Converter: Built-in with dual CV outputs
• Eurorack Compatible: CV patchbay works with modular systems
• No Power Indicator: Status determined by LFO LED activity

Controls

• High-quality knobs of various sizes, 3-way switches

Physical Specifications

• Dimensions: 225 x 160 x 55 mm
• Construction: Metal enclosure with wooden edges
• Color: Grey and fluorescent green

Power

• 12V AC adapter (external)