This is a Korg Delta DL-50, Korg’s classic analog string synth from around 1979–84. It’s two instruments in one 49-key keyboard: a lush Strings section and a Synth section with a real 24dB/octave Korg filter. Every key plays its own note, so you can play full chords on both sections, either separately or layered.

I purchased this professionally fully serviced in house from the highly reputable Three Wave Music in NJ (https://reverb.com/shop/threewavemusic) just a few months ago. Beautiful synth, just not conducive with my setup.

The Delta is known for its thick, warm string pads, and the synth section takes it well beyond a basic string machine. You can sweep the filter across full chords for big Human League / Flock of Seagulls–style textures. It was used by the Human League, A Flock of Seagulls, Ladytron and LCD Soundsystem.

Both sections have their own outputs, so you can record or process the strings and synth separately. There’s also a combined output. It has CV/gate connections for working with other analog gear, and it’s built solid on a wooden base, made for the road.

Specs:

• 49-key keyboard, fully polyphonic
• Strings section: 16' and 8' footage sliders, Bass and Treble tone controls, Attack and Release, vibrato (depth and speed)
• Synth section: 16', 8', 4' and 2' footage sliders, white noise, 24dB/oct filter (low-pass / band-pass / high-pass) with cutoff, resonance and envelope amount (+/–), keyboard tracking, ADSR envelope, LFO
• Joystick for pitch bend and modulation
• Single / multiple trigger modes
• Separate Strings and Synth outputs, plus a combined output
• CV and gate/trigger inputs and outputs
• No MIDI, no patch memory (all hands-on analog)
• Voltage: 120V US

The Delta is roughly 34 × 14 × 5.5 inches and about 28 lb