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Vintage synths & drum machines
Vintage Synthesizers
Korg Delta synthesizer-strings keyboard, three-quarter view: 49-key keyboard in a black case, dark brown-black panel with gold legends, knobs and short sliders in synthesizer and strings sections, joystick panel left of the keys
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Korg · Analog polysynth · Pre-MIDI classics

Korg Delta

Korg's Delta (DL-50) arrived in 1979, the same season as the Lambda and Sigma, as a 49-key string machine with a simple synth built in. It has two sections, Strings and Synth, each with its own audio output. The Strings section has 16' and 8' footages, bass and treble tone controls, and attack and release. The Synth section adds four footages from 16' down to 2', white noise, a full ADSR, and a 24 dB per octave low-pass filter that also offers high-pass and band-pass settings. Every key can sound at once, but the notes share the filter and envelope, so it's paraphonic in the way most string machines are. A joystick handles pitch bend and modulation, and CV and gate sockets let you drive it from other gear. The Human League, Ladytron and Broadcast all used one. Buy a Delta for lush strings and sweeping pads, and check the synth section closely, because that's the half that usually fails.

Spec at a glance

Brand
Korg
Type
Analog polysynth
Voices
Fully polyphonic
Keys
49 keys
MIDI
No (pre-MIDI)
eBay asks (Oct 5, 2026)
$850–$900

What to check before you buy

The fault reported most often is a silent synth section while the strings keep working. Repairs on Deltas with that fault replaced the transconductance amplifier chips and the filter capacitors next to them.

  1. 01Synth section: Ask for a video playing the synth section alone with the strings turned off. It should sound clearly across the whole keyboard.
  2. 02Strings: Ask for a clip of the strings at 16' and 8' with the attack and release moved. Both footages should sound even, with no dead notes.
  3. 03Filter modes: Ask for a clip sweeping the synth filter in low-pass, high-pass and band-pass. Each mode should sweep smoothly without crackle.
  4. 04Keys: Ask for a video playing all 49 keys with both sections up. Every key should sound in both sections.
  5. 05Outputs: Ask whether the separate Strings and Synth outputs have been tested. Both should carry sound with no hum.
  6. 06Joystick: Ask for a clip moving the joystick through pitch bend and modulation. It should move freely and return to center.

Buying guide

Which one to buy

§ Oct 5, 2026

Only three Deltas are for sale, two of them sold as-is, so the $850–900 delivered band isn't much of a market read. The one we'd buy is the unit from Japan titled Very Good Condition at $885 delivered, since the as-is ones ask $850 and $900 and give you almost no discount for the risk. The synth section is the half that usually fails, so ask for a video of it alone with the strings off, played across all 49 keys. It ships from Japan, so check the voltage plate, because a 100V unit needs a step-down transformer on US 120V mains.

Listed now
3
For parts
1
Typical ask
$850–$900
Full range
$600–$735

Delivered prices include shipping as eBay quoted it to a US address on Oct 5, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.

Snapshot

For sale on eBay

3 of 3 listed

Checked . Some may have sold.

Delivered prices include shipping as eBay quoted it to a US address on Oct 5, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.

Prices change daily. The live eBay search shows everything listed now, including anything new since Oct 5, 2026.

See every listing on eBay ↗eBay search

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