When Eko decided to close its synthesizer division in 1979, they went out with something genuinely odd and charming: a preset machine that actually lets you break the rules. The P15 sits in that fascinating middle ground between a fixed sound bank and a real synthesizer, giving you 15 instrument emulations that sound nothing like their names but everything like warm, characterful analog warmth.
The heart is a single VCO with switchable sawtooth and square waves feeding into a self-resonating 24dB/oct lowpass filter. In preset mode, you get those 15 sounds ready to go, but the real magic happens when you flip to Manual mode and start tweaking the VCF and VCA sections independently. The filter has dedicated Cutoff and Resonance controls, while both the filter and amplifier envelopes give you Attack and Decay (or Sustain) to reshape the character. A single LFO with sine and square options can modulate the filter, amplifier, or oscillator at rates approaching self-oscillation, controlled by Wah-wah, Tremolo, and Vibrato intensity sliders. There's also a Glide control for smooth pitch transitions between notes. The whole thing runs on fully analog circuitry despite the "Digital System" label on the front panel, which was just marketing speak for using integrated circuits.
The P15 has developed a small but devoted following among collectors and experimentalists who appreciate its quirky character and surprisingly playable interface for something so limited on paper. It's rare enough that finding one in working condition requires patience, and repair can be tricky since some of the chips inside are genuinely hard to source. But for players who love the sound of warm, slightly unpredictable analog character and don't mind working within constraints, it's a genuinely rewarding machine.
