Sequential Circuits

“This one is in excellent cosmetic condition and working 100%. It is ready to be played and needs nothing! As the title says, this one has the Turbo CPU Upgrade with Midi. It has a custom midi bezel on one of the wood sides so there is no irreversible damage and misaligned holes drilled into the metal housing. It also has the Techsmechs TM-2 keyboard replacement.” Click here to visit listing on eBay

“The famous Sequential Circuits Pro One mono synth.

A classy 2 oscillator machine with a fabulous rich, deep, punchy, awesome sound.
In very good condition, not Mint, not Excellent, but certainly ‘very good’. Early J-wire model.
Set 220 volts (can be set to 110).

Sold as seen. One key has a previous glue repair on it as you can see in the pics but all keys working fine.” Click here to visit listing on eBay

” Great condition Sequential Circuits Pro One vintage synthesizer, just serviced by Synthchaser. This is the nice J-wire keybed version, with the contacts just cleaned and smooth new bushings installed. Other work done included power supply recap, new power cord, cleaning pots & switches, and calibration. Road case has no foam, so synth will be packed well inside the case. See attached pictures. Local pickup is welcome and encouraged.” Click here to visit listing on eBay

“Sequential Circuits Pro One. Completely overhauled and serviced by top industry professional. Works amazingly. I have made some videos on YT of it in action. Search Pro-One Awesome Synth Power. Used on Goldbug – Whole Lotta Love for the synth solo and intro to b-side. The modulation matrix enables FM synthesis as well. You can see why Yamaha had to make an FM synth after this was invented, but a digital synth is no way as instant or as much fun or as powerful as this. There is possibility for at least three operators (as they are known in the Yamaha-speak) and of course it is also a punishing straight analogue synth to rival the Mini Moog. ( But there’s no FM on a Mini Moog.) Also available Roland MPU 101 in separate listing for if you need MIDI control. What more can I say? Been postponing selling it as enjoyed making the online videos so much. Would probably recommend pick-up in person if you can. (However, all my items are packed like Tutankamun and never had a problem yet, but it is serious vintage.) You can see in the video every module working including onboard sequencer and trigger/LFO functions. There are also explanations with the videos of how to use the matrix to get the FM synthesis.” Click here to visit listing on eBay

“Great condition Sequential Circuits Pro One vintage synthesizer, just serviced by Synthchaser. This is the nice J-wire keybed version, with the contacts just cleaned and smooth new bushings installed. Other work done included power supply recap, new power cord, cleaning pots & switches, and calibration. Road case has no foam, so synth will be packed well inside the case. See attached pictures. ”
Click here to visit listing on eBay

“In extremely good condition. I bought several pieces of pro audio equipment and it appears like none of it has been used if it has it was used with great care.” Click here to visit listing on eBay

“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