Built during the late 1970s synthesizer boom, the Korg Delta represents a fascinating middle ground between string machine and polysynth, using divide-down oscillator technology that traces back to vintage transistor organs rather than the voltage-controlled oscillators found in most synthesizers of its era.
The Delta splits its architecture into two independent sound sections that can be played together or separately with their own outputs. The Strings section uses two fixed pitch sliders at 16' and 8' with a simple two-stage envelope and a two-band EQ for shaping tone, while the Synth section offers four freely mixable octave sliders, a white noise generator, a resonant 24dB per octave low-pass filter with high-pass and band-pass options, and full ADSR envelope control. A joystick on the left side of the 49 full-size keys handles pitch bending and modulation in real time. The synth accepts CV and gate inputs for external control and includes separate trigger modes for single or multiple triggering across both sections.
The Delta's solid construction, reinforced with a wooden base and weighing 10 kilograms, was built for road use and has held up remarkably well across decades. It has no internal memory or MIDI, keeping things refreshingly straightforward, though the ability to mix and layer the two sections together creates that classic lush, orchestral sound that made it a favorite among post-punk and new wave acts like Human League, Flock of Seagulls, and Ladytron. The string sounds are intentionally basic, but that simplicity pairs beautifully with the more complex synth section, and full polyphony across all 49 keys means you'll never run out of voices.
