Pro One

“See photos for example physical condition. Item has been Tested for power only and the red LED sensor lights up when plugged in & turned on. Some key’s are down / not buoyant as shown on photo’s. Cord has some cosmetic issues as shown but works fine.” Click here to visit listing on eBay

“Up for Sale, the Iconic Sequential Circuits Pro One Synthesizer. Fully functional and in good cosmetic condition. All the knobs, switches and keys produce sound. Although, all the keys produce sound, they are uneven. Some are higher than others. But, that’s not a issue because I usually use an external Arturia sequencer to program this synth via cv. I tried my frind’s Behringer clone next the original pro one qnd honestly idoesnt have the same vintage sound and power and the white noise is weak compared to the original. I’m selling it because I need money for rent otherwise I will keep this amazing beast. If you love that agressive metallic Depeche Mode sound or Berlin type techno this is the synth for you. It sounds like no other! ” Click here to visit listing on eBay

“Sequential Circuits Pro One Fully disassembled, cleaned inside and out by Chris Hewitt at This Old Synth in San Jose, California. Working perfectly. Professionally installed the MTG MIDI + Turbo cpu in the SCI and the more desirable J-wire keyboard. This process was performed by an expert vintage synth tech. The end result is an instrument that’s better than the rest and is priced accordingly. Ready to play, no excuses. The wooden sides were replaced with brand new replicas made by a third party. Shipping is free within the United States. I’d consider shipping internationally if you paid for shipping costs.” Click here to visit listing on eBay

“This is a Sequential Circuits Pro One synthesizer.
I am including a DI box in the package (as this eliminates audio hum).

The main circuit board was built in April 1982.
The serial number on the board and the one on the casing don’t match, which would suggest to me that the synth is a combination of two previous synths.
I have made a few improvements / fixes to the synth since I bought it:
A complete clean inside and out. All switches have been cleaned as have all key contact points.
Some capacitors have been replaced.
An internal ribbon has been replaced (bought from Wine Country Productions Inc).
I have bought wooden end cheeks for the synth, since these were missing.
I have also replaced a mod wheel (which was broken) with a clear acrylic wheel.
There is audio hum. Apparently, this is a very common feature of the Pro One and is due to a ground loop (an original design oversight).
The DI box eliminates the hum, and this is why I am providing the DI box with the synth.
I’ve tuned the synth using the variable resistors (pots). The tuning is pretty good across the keyboard, but will no doubt need readjusting from time to time.” Click here to visit listing on eBay

“This is a Sequential Circuits Pro One synthesizer.
I am including a DI box in the package (as this eliminates audio hum).

The main circuit board was built in April 1982.
The serial number on the board and the one on the casing don’t match, which would suggest to me that the synth is a combination of two previous synths.
I have made a few improvements / fixes to the synth since I bought it:
A complete clean inside and out. All switches have been cleaned as have all key contact points.
Some capacitors have been replaced.
An internal ribbon has been replaced (bought from Wine Country Productions Inc).
I have bought wooden end cheeks for the synth, since these were missing.
I have also replaced a mod wheel (which was broken) with a clear acrylic wheel.
There is audio hum. Apparently, this is a very common feature of the Pro One and is due to a ground loop (an original design oversight).
The DI box eliminates the hum, and this is why I am providing the DI box with the synth.
I’ve tuned the synth using the variable resistors (pots). The tuning is pretty good across the keyboard, but will no doubt need readjusting from time to time.”
Click here to visit listing on eBay

” Retro Gear Shop is a high-end boutique store located in Nashville, Tennessee.

Sequential Circuits Pro One #1015
For sale is a rare vintage Sequential Circuits Pro One analog monophonic synthesizer. This is a great synth that sounds excellent. Phat basses, leads and effects with a simple but fun built in arpeggiator and sequencer. This one is in excellent shape and fully functional. This is the more desirable J-wire keyboard version. A classic awesome mono-synth and worthy addition to any collector’s or sound designer’s studio.” Click here to visit listing on eBay

“Sequential Circuits Pro One Vintage Synthesiser.

This Pro One is in great condition, with only the handful of minor blemishes that are to be expected on a vintage instrument of this age. I’ve done my best to picture these.

The keyboard and all other features work perfectly.

Unfortunately the two labels (Pro One & Sequential Circuits) have been lost over the years, but otherwise everything is as it should be.

Lovely piece of vintage gear and solid investment.” Click here to visit listing on eBay

“For sale: A gorgeous example of the classic Sequential Circuits Pro One. Fully restored around 8 years ago by the famous Kent Spong on behalf of RL Music, it is almost blemish free apart from one or two minuscule marks. It was fully serviced only a week ago by Ben at Cyberwave Studios. Cleaned inside and out the j wire keybed has been cleaned and re set. The machine has been tuned and calibrated and a new noise generator installed. The Wooden end panels are undamaged and the switches and knobs are smooth and solid. It really is an absolute joy to play and sounds incredible. In its current condition you are looking at years of big bass, silky leads, punch and grit before you will need to have it serviced again. I really will be sad to see it go. ” Click here to visit listing on eBay

“This is a Sequential Circuits Pro One synthesizer.
I am including a DI box in the package (as this eliminates audio hum).

The main circuit board was built in April 1982.
The serial number on the board and the one on the casing don’t match, which would suggest to me that the synth is a combination of two previous synths.
I have made a few improvements / fixes to the synth since I bought it:
A complete clean inside and out. All switches have been cleaned as have all key contact points.
Some capacitors have been replaced.
An internal ribbon has been replaced (bought from Wine Country Productions Inc).
I have bought wooden end cheeks for the synth, since these were missing.
I have also replaced a mod wheel (which was broken) with a clear acrylic wheel.
There is audio hum. Apparently, this is a very common feature of the Pro One and is due to a ground loop (an original design oversight).
The DI box eliminates the hum, and this is why I am providing the DI box with the synth.
I’ve tuned the synth using the variable resistors (pots). The tuning is pretty good across the keyboard, but will no doubt need readjusting from time to time.” Click here to visit listing on eBay

” Up for sale is a highly cool Sequential Circuits Pro One with the proper J Wire Keybed. NOT the inferior membrane keybed.

As you can see this classic beast of a synth has been properly cared for all its life. Never abused or mistreated : ) It looks amazing and it plays amazing. There is nothing like a real Pro One. Basses, Leads, Efx, Swells and more… this synth has just a jawdropping sound. Perfect addition to any synth freaks collection.

It all works great, plays great and is properly tuned and scaled across many octaves. But as you’d know if you play, collect and use synths of this era. It MAY or may not need a scaling / calibration after being in transit.. just stating for full disclosure. THIS 40 year old electronic synthesizer is not applicable for returns for any reason. ” Click here to visit listing on eBay

“Up for sale is a highly cool Sequential Circuits Pro One with the proper J Wire Keybed. NOT the inferior membrane keybed.

As you can see this classic beast of a synth has been properly cared for all its life. Never abused or mistreated : ) It looks amazing and it plays amazing. There is nothing like a real Pro One. Basses, Leads, Efx, Swells and more… this synth has just a jawdropping sound. Perfect addition to any synth freaks collection.

It all works great, plays great and is properly tuned and scaled across many octaves. But as you’d know if you play, collect and use synths of this era. It MAY or may not need a scaling / calibration after being in transit.. just stating for full disclosure. THIS 40 year old electronic synthesizer is not applicable for returns for any reason. ” Click here to visit listing on eBay

“For sale: A gorgeous example of the classic Sequential Circuits Pro One. Fully restored around 8 years ago by the famous Kent Spong on behalf of RL Music, it is almost blemish free apart from one or two minuscule marks. It was fully serviced only a week ago by Ben at Cyberwave Studios. Cleaned inside and out the j wire keybed has been cleaned and re set. The machine has been tuned and calibrated and a new noise generator installed. The Wooden end panels are undamaged and the switches and knobs are smooth and solid. It really is an absolute joy to play and sounds incredible. In its current condition you are looking at years of big bass, silky leads, punch and grit before you will need to have it serviced again. I really will be sad to see it go. ” Click here to visit listing on eBay

“Sequential Circuits Pro One Vintage Synthesiser.

This Pro One is in great condition, with only the handful of minor blemishes that are to be expected on a vintage instrument of this age. I’ve done my best to picture these.

The keyboard and all other features work perfectly.

Unfortunately the two labels (Pro One & Sequential Circuits) have been lost over the years, but otherwise everything is as it should be.” Click here to visit listing on eBay

“Sequential Circuits Pro One Analogue Synthesiser. In working condition with a made to measure flight case and original manual. There is one potentiometer knob missing. Recommended to have it serviced to get a better action on the keys.” Click here to visit listing on eBay

“Absolutely stunning boxed Pro One, Rev 1.2 dated 12th June 1981 on the main board, so just turned 40 years old. In breathtaking condition with only very minor age related wear, has been kept in it’s box for many years and looks almost like it just came out of the factory. All original dials, wood ends and badges etc., and the original box even has the polystyrene ends present and complete. I can only find one other boxed example sold worldwide in the last 5 years, that was in the US/Canada, so this is a really rare piece of synth history, not just this side of the Atlantic but anywhere worldwide. Needless to say the Pro One, along with the Minimoog Model D, are the mono synths that shaped modern music

Serial number is in the 5000’s which is the absolute sweet spot for a Pro One, signifying the preferred J-Wire keyboard and the case-mounted rather than board-mounted power supply (you want one with a serial number between 1500 and 8500 ideally, this is bang in the middle). Has recently been carefully cleaned inside and out, keybed was removed and cleaned, a full set of new rubber key bushings from Vintage Vibe in the US have been fitted, keys removed and individually cleaned (the white ones are super-bright, no major discolouration), dials removed and individually cleaned, all pots and switches treated with DeOxit, and the wood ends lightly fed with a premium Danish Oil to nourish the timber and bring out the grain. The odd light evidence of age and use of course, the ends and shiny bits inevitably pick up small signs of wear, but it’s hard to imagine there being a better example out there. Hasn’t been over restored, just sympathetically refurbished. It’s looks amazing and sounds incredible.

The main circuit board shows off the classic markings you expect to see in a Pro One and original Prophet 5 etc., including the Hindu god ‘Vishnu’ stamp, the beautiful Rev 1.2 and ‘toadstools’ marks flowed on in solder, and the hand written calibration notes and build date. The boards in these are a real work of art. I have many more pics than the 12 included here, so if you need more or wish to view please ask.” Click here to visit listing on eBay

“This Sequential Circuits Pro-One Model 100 is remarkably well-preserved, with nigh flawless silkscreened graphics and all original knobs and switches intact. The wood sides show sparingly little wear and the serial number and original factory warranty stickers are intact on the back of the enclosure.” Click here to visit listing on eBay

“Incredible monosynth. I bought this one in 2019 and have made a lot of great tracks with it! I’m now making a different style of music so I don’t need as many analogue synths anymore.

Selling it for the same price I bought it for (so no offers please!)

A previous owner upgraded it with midi, and it comes with a great flight case.” Click here to visit listing on eBay

“This SCI Pro One is in excellent condition. It’s fully functional and sounds great. It was recently serviced and is ready to go. All keys trigger properly, pots are clean and switches all working. This is the more desirable J-wire keyboard version. This is a classic awesome sounding mono-synth. Also included is the MTG Turbo Kit (not installed). If you would like our techs to install it we can do that for actual cost, estimated 2-3 week turnaround. Estimated installation cost $300 but this is just an estimate. Message us if interested in having the MTG Turbo kit installed. ” Click here to visit listing on eBay

“Legendary analogue synthesizer from 1981. Without a shadow of doubt the most powerful mono synth ever produced. This thing is completely devastating for bass, but also excels at leads, drones, percussive sounds and all kinds of other complete madness. A truly wild and amazing instrument. The real deal – none of this modern clone/reproduction business.

This one has the much more desirable J-Wire keyboard – and is serial number 6732. A bit of research online will reveal that this is what you want – the first couple of thousand has problems with the internal power supply and the ones after 8000 had the badly designed membrane keyboard. The synth was serviced a couple pf years ago and is working flawlessly (I can provide the service invoice). The synth is in immaculate condition cosmetically. Wooden end cheeks are in really nice condition. All in all for a 40 year old unit this is a really incredible example. An amazing and inspiring instrument but also a solid investment, the price of these things is rising all the time these days.” Click here to visit listing on eBay

“This listing is for 1 x Sequential Circuits Pro One Analog Synthesizer & Original Box (actual item in images).

The unit works as it should and is in excellent condition (please see images).

All pots have been cleaned and all switches/buttons work.

All key contacts cleaned. It has the more desirable J-wire version keyboard.

The original box is showing its age but is intact.” Click here to visit listing on eBay

“I replaced the cord and fired it up. Appears like all the knobs and switches are working. Both the wheels work. The pots all need to be cleaned up, they are scratchy. Switches too. Keyboard needs to be disassembled and restored. I have had it since the late 90’s. When I put away for storage everything worked. If I had the time I would restore it myself…..” Click here to visit listing on eBay

“Sequential Circuits Pro One Synthesizer Powers On *no Sound*. Condition is “Used”.

It powers on, but there is no sound. Knobs do work because there is static when they are turned. Maybe just needs a good cleaning and the keys to be serviced” Click here to visit listing on eBay

“Legendary analogue synthesizer from 1981. Without a shadow of doubt the most powerful mono synth ever produced. This thing is completely devastating for bass, but also excels at leads, drones, percussive sounds and all kinds of other complete madness. A truly wild and amazing instrument. The real deal – none of this modern clone/reproduction business.

This one has the much more desirable J-Wire keyboard – and is serial number 6732. A bit of research online will reveal that this is what you want – the first couple of thousand has problems with the internal power supply and the ones after 8000 had the badly designed membrane keyboard. The synth was serviced a couple pf years ago and is working flawlessly (I can provide the service invoice). The synth is in immaculate condition cosmetically. Wooden end cheeks are in really nice condition. All in all for a 40 year old unit this is a really incredible example. An amazing and inspiring instrument but also a solid investment, the price of these things is rising all the time these days.” Click here to visit listing on eBay

“Sequential Circuits Pro One Vintage Analog Mono Synthesizer. For parts or repair: it makes noise, but not sure why it’s not fully working. Maybe you can fix it! Cosmetically perfect.”
Click here to visit listing on eBay

“This listing is for 1 x Sequential Circuits Pro One Analog Synthesizer & Original Box (actual item in images).

The unit works as it should and is in excellent condition (please see images).

All pots have been cleaned and all switches/buttons work.

All key contacts cleaned.” Click here to visit listing on eBay

“Sequential Circuits Pro-One synthesiser. I’ve own this Beautiful instrument for over 10 years and I bought it from the original owner. Plays lovely and is a real classic, whoever wins will own a beautiful synth.”
Click here to visit listing on eBay

“We only accept PayPal payments.
Please pay within 5 days after auction is finished.” Click here to visit listing on eBay

“Legendary analogue synthesizer from 1981. Without a shadow of doubt the most powerful mono synth ever produced. This thing is completely devastating for basslines, but also excels at leads, drones, percussive sounds and all kinds of other complete madness. A truly wild and amazing instrument. The real deal – none of this modern clone/reproduction business. The synth was serviced a couple pf years ago and is working spot on. There is one control knob (Osc A volume) missing as can be seen in the photos, but the actual potentiometer still functions perfectly and can be used like normal. There were none available at the time the unit was serviced, but they are readily available from a few sources at the moment and cost just under £10. The unit is in really nice overall condition cosmetically. There’s a hairline mark on the casing just to the left of the pitch/mod wheel as can be seen in the photos but this is superficial and has no affect on functionality. Wooden end cheeks in really nice condition. All in all for a 40 year old unit this is a really fine example.” Click here to visit listing on eBay

“SEQUENTIAL CIRCUITS PRO-ONE –

Fully working classic analogue mono synth. Great for bass

Minor service in the last year:
Keyboard contacts replaced
LFO pot replaced” Click here to visit listing on eBay

“Sequential Circuits Pro-One Prophet Sci Analog Synthesizer Vintage Circuit” Click here to search for synths on eBay