MARS Polyphonic Tube Synthesizer

Imagine a synthesizer where four glowing vacuum tubes rise like sentinels from a 5U rackmount chassis, promising the world's first truly polyphonic tube sound—raw, warm, and utterly alive.

This hybrid beast pairs digital oscillators built on the vintage R-2R DAC TDA1387—four voices strong, each with Basic mode (sine, triangle, saw, fixed pulse widths), Pulse, Ensemble, and filtered Noise options, plus PWM and FM capabilities. They feed into a shared second-order voltage-controlled tube filter with cutoff, self-oscillating resonance, and overload grit, followed by a tube VCA echoing classic opto compressors like the LA-2A, and a triode asymmetric overdrive for extra harmonic bite. Modulation shines with dual HADSR envelopes (pre-delay, multi-retrigger), a versatile LFO (morphing saw-triangle-saw or pulse-square-pulse, sync/restart), sample & hold, and noise gen—all routed via a hands-on 4-channel matrix without menu diving. Switch between mono, duo, or 4-voice poly modes with portamento/legato, and integrate via MIDI in/out, 4x CV/gate, USB to its DAW plugin, external audio in, master/headphone outs, even a Nixie lamp display. It ships with spare tubes for longevity.

Since shipping earlier this year, players dig its punchy FM leads, acidic basses, and lush pads, praising the tube path's organic crunch that stands apart in Eternal Engine's lineup from the duophonic APPARATUS. A few note the shared filter keeps poly voices cohesive rather than fully independent, but that unity fuels its signature vibe.