Korg · Analog polysynth · Pre-MIDI classics
The Lambda (ES-50) came out in 1979 alongside the Delta, and it's an ensemble keyboard built around preset sounds. Its 49 keys are fully polyphonic thanks to divide-down oscillators, with three detunable VCOs behind them. The presets sit in two groups. The percussive group covers electric piano, clavi, piano and harmonics, with tremolo. The ensemble group covers brass, organ, chorus and strings, with adjustable attack and release. Each note gets two VCAs, which gives it more per-note shaping than a typical string machine, and a stereo BBD chorus and tremolo spreads the sound wide. The rear panel has a sustain pedal input, an expression CV input, a trigger output and stereo outs. Its choir and string sounds are why people want one today. It's a preset instrument with a short list of controls, so judge a listing on whether every sound and every key works, and plan for a service on one that's never had it.
Polynominal's review says aging Lambdas often need servicing. The stereo chorus and tremolo run on BBD delay chips, so that effect is the first thing to hear in a seller's video.
Buying guide
Only four Lambdas are for sale, all shipping from Japan, so the $2,925–3,025 delivered band isn't much of a market read. We'd buy one of the two titled serviced, at $2,987 and $2,989 delivered, since aging Lambdas often need servicing and these two say they've had it. Ask for a video of the strings and chorus presets with the ensemble on, because the stereo chorus runs on BBD chips and should sound wide with no crackle or pitch wobble. Check the voltage plate too, since a 100V unit needs a step-down transformer on US 120V mains.
![KORG LAMBDA ES-50 [232271]](https://i.ebayimg.com/images/g/HmMAAeSwfEhqrLzr/s-l500.jpg)
$2,793.00delivered
The lowest price on a Lambda at $2,793 delivered, with Best Offer open. The title is just the model and a stock number, so ask when it was last serviced and for a video of every preset.
KORG LAMBDA ES-50 [232271]
$2,987.00delivered
Titled serviced, tested and works, for $194 more than the cheapest one. That's a small premium on a keyboard that often needs a service by now.
KORG LAMBDA ES-50 Vintage Polyphonic Ensemble Synthesizer Serviced Tested Works
$2,989.00delivered
Titled fully serviced, at $2,989 delivered with Best Offer open. Ask what the service covered and whether the chorus was part of it.
KORG Lambda ES-50 Vintage Polyphonic String Synthesizer Fully Serviced Japan
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
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.
Used$2,793.00delivered
$2,793.00 · free shipping
Buy It Now$2,793.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Good buy
No tested or serviced claim in the title. Ships from Japan.
Seller: ishibashimusic
100% positive
Serviced$2,987.00delivered
$2,987.00 · free shipping
Buy It Now$2,987.00
Good buy
Titled serviced, tested and works. Ships from Japan.
Seller: asterisk_llc
99.6% positive
Serviced$2,989.00delivered
$2,989.00 · free shipping
Buy It Now$2,989.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Good buy
Titled fully serviced. Ships from Japan.
Seller: shopmin-japan
99.8% positive
Used$3,071.49est. delivered
$2,741.49 + $330.00 shipping
Buy It Now$2,741.49
Our take
Titled tested, but $330 shipping makes it the most expensive here at $3,071 delivered.
Seller: tokyo_depo
100% positive
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