midiphy - zetaSID

zetaSID is a complete SID-based synth voice for Eurorack, built around MIDIPHY's modern emulation of the famous Commodore 64 sound chip and the considerably deeper MIDIbox SID synthesis engine. On its own it works as a monophonic CV/Gate instrument with three oscillators, filter, envelopes, six LFOs, extensive modulation, arpeggiators and wave sequencing — all edited from a tiny OLED, encoder and button. The result can certainly do the familiar chiptune bleeps and rapid-fire arpeggios, but there is enough machinery here for basses, leads, drones and decidedly less nostalgic forms of digital misbehaviour too.

The cool thing is that you also have the ability to connect several zetaSIDs through MIDIPHY's phybus. Two modules can form a true stereo voice, while as many as twelve can be combined into a six-voice stereo polysynth. The modules then cooperate rather than simply sitting next to each other: one screen can be editing oscillators while another handles the filter or modulation section, and patch changes and internal virtual connections can be shared across the whole cluster of zetaSIDs. If you also decide to add MIDIPHY's nexusMIDI expander, the system can be played over MIDI, leaving the front-panel CV and Gate inputs available as additional modulation sources. It's quite a clever way of making a very small module expandable without turning the individual module into a miniature control-room nightmare.

There are three different synthesis engines to work with. Lead is the large general-purpose SID architecture with its modulation matrix, four wave sequencers and three independent oscillator arpeggiators; Bassline turns the system towards 303-ish sequencing with slide and accent; and Drum provides up to 16 percussion instruments drawn from 19 algorithmic drum models and old-school C64 effects. A single zetaSID is already a surprisingly substantial little synthesizer — adding more simply changes the scale of this idea.

Features:

• Eurorack synth voice based on SID chip emulation and the MIDIbox SID engine
• Three synthesis engines: Lead, Bassline and Drum
• Lead engine with three oscillators, six LFOs and two envelopes
• Eight modulation paths with numerous modulation sources and algorithmic operations
• Four integrated wave sequencers based on classic C64-style SID wavetables
• Three independent per-oscillator arpeggiators
• 24 × 14 event trigger matrix
• Bassline engine with eight 16-step patterns
• Bassline sequencing with gate, slide, accent and additional parameter automation
• Drum engine with up to 16 instruments
• 19 parametric drum algorithms
• Integrated SID filter emulation
• 100 factory patches in ROM
• OLED display with graphical oscillator, filter, arpeggiator and parameter visualisation
• CV input configurable for −5 to +5 V or 0 to +10 V
• CV input defaults to 1 V/oct pitch control
• Gate input
• Eurorack-level audio output
• MIDIPHY phybus connection for linking modules and sharing control/data internally
• Two zetaSIDs can be linked as one true stereo voice
• Up to twelve zetaSIDs can form six stereo polyphonic voices
• Multi-module unison mode with individual detuning
• Cooperative user interface across linked zetaSID modules
• Optional nexusMIDI expansion for MIDI control
• Supports ASID playback of SID files via MIDI
• Virtual phybus patching with session recall
• Optional microSD storage for patches and up to 100 sessions
• Limited compatibility with MIDIbox SID V2 Lead, Bassline and Drum patches
• Web-based patch editor available when used with nexusMIDI