Sequential Circuits · Analog polysynth · Early MIDI era
The Prophet-600 is where MIDI starts. Dave Smith and Sequential engineer Chet Wood proposed a universal synth interface to the Audio Engineering Society in 1981, Roland, Yamaha, Korg and Kawai helped refine it, and Smith dated the 600's first shipments to December 1982, making it the first MIDI product sold. At the January 1983 NAMM show a 600 was linked to a Roland synth, the first public MIDI connection. It keeps the Prophet-5's general layout with cheaper knobs and switches, and has six voices of Curtis oscillators, 100 memories, a sequencer and an arpeggiator. Sound On Sound wasn't kind to it in 1999, citing slower digital envelopes, steppy controls and tuning that wandered with the weather. The open-source GliGli firmware fixes a lot of that. It swaps the Z80 processor for a Teensy++ board that plugs into the same socket and adds MIDI clock sync for the arpeggiator, unison detune and a dedicated vibrato, and it's still maintained as v2022. Buy a modded one if you'll play it, and a clean stock one if you collect.
Sound On Sound called the 600 unreliable, with tuning that shifts with temperature and humidity. Owners also report keys that won't trigger and transformer hum, and the 25 panel pots have nylon shafts that can break.
Buying guide
We'd take the Prophet-600 titled tested with the GliGli mod at $1,998 delivered, since that firmware fixes a lot of the 600's steppy controls and slow envelopes, or the US one titled recently serviced at $2,045. There are about 8 for sale and most ask $1,950–2,125 delivered; the outliers are a $1,105 as-is parts unit, a $1,474 one from a zero-feedback seller and a dealer unit at $2,757 with no service claim. Ask for a video of the six voices one at a time and every key, since Sound On Sound called the 600 unreliable with tuning that drifts with temperature, and check that no knob spins loose, because the pot shafts are nylon. Units from Japan need a voltage check, and a 100V one needs a step-down transformer on US mains.
$1,936.19est. delivered
The cheapest Prophet-600 from an established seller at $1,936 delivered, titled with a pedal and a case, which helps when a big keyboard ships. It isn't titled tested, so ask for a video of the six voices one at a time and every key.
Sequential Circuits Prophet 600 Excellent Condition w/ pedal in case
$1,998.00delivered
Titled tested and fitted with the GliGli mod, the open-source firmware that fixes a lot of the 600's quirks, for $1,998 delivered inside the band. It ships from Japan, so check the voltage plate, since a 100V unit needs a step-down transformer on US mains.
Sequential Circuits Prophet-600 GliGli Mod 6-Voice Analog Synth Tested Japan
$2,045.00est. delivered
Titled recently serviced, from a US seller, at $2,045 delivered in the middle of the band. Ask what the service covered and whether any knobs spin loose, since the pot shafts are nylon.
SEQUENTIAL CIRCUITS PROPHET 600 SYNTHESIZER RECENTLY SERVICED IN AMAZING SHAPE!
$1,105.00est. delivered
Sold as-is for parts at $1,105 delivered, about $850 under the band. Price it as a repair job on a 40-year-old poly, and ask what the seller knows is wrong.
Sequential Circuits Prophet-600 Keyboard Analog Synthesizer Vintage as-is parts
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$1,936.19est. delivered
$1,799.99 + $136.20 shipping
Buy It Now$1,799.99
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.
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Good buy
Titled with a pedal and case. Seller is at 98%, so read the recent feedback.
Seller: aldervista
98% positive
Used$1,998.00delivered
$1,998.00 · free shipping
Buy It Now$1,998.00
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.
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Good buy
GliGli mod and tested, per the title. Ships from Japan, so check the voltage plate.
Seller: shopmin-japan
99.8% positive
Serviced$2,045.00est. delivered
$1,895.00 + $150.00 shipping
Buy It Now$1,895.00
Good buy
Titled recently serviced.
Seller: scoop_synthesizer_world
100% positive
For parts$1,105.00est. delivered
$1,025.00 + $80.00 shipping
Buy It Now$1,025.00
Project piece
Sold as-is for parts. A restoration project.
Seller: retrogearshop
100% positive
Used$2,099.94delivered
$2,099.94 · free shipping
Buy It Now$2,099.94
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.
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Our take
The title says Read, so look for a stated fault in the description.
Seller: capcityoutlet
99.7% positive
![SEQUENTIAL CIRCUITS INC Prophet-600 [04423]](https://i.ebayimg.com/images/g/xFoAAeSwSHBqhB1m/s-l500.jpg)
Used$2,130.00delivered
$2,130.00 · free shipping
Buy It Now$2,130.00
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.
Our take
Ships from Japan. Check the voltage plate.
Seller: ishibashimusic
100% positive
Used$1,474.49est. delivered
$1,300.00 + $174.49 shipping
Buy It Now$1,300.00
Check the seller
Titled with a case, from storage, by a zero-feedback seller. Pay only through eBay checkout.
Seller: soundscapes61
No feedback yet
Used$2,757.33est. delivered
$2,599.99 + $157.34 shipping
Buy It Now$2,599.99
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.
Priced high
Dealer listing at $2,757 delivered, about $630 over the band with no service claim in the title.
Seller: 123synthland
100% positive
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