Sequential Circuits Pro One

“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

Sequential Circuits Pro One

“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

“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

Sequential Circuits Pro One

“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

“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

” Sequential Circuits Pro-One synthesiser lightly used without stand. Condition is “Used”. Selling this on behalf of the estate of my partners brother who sadly passed away last year. We don’t know much about these. No box or documentation. We haven’t tested it hence a low starting price and no reserve. Buyer collection only from St Albans in Herts.” Click here to visit listing on eBay

Sequential Circuits Pro One

“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

“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. ” Click here to visit listing on eBay

Sequential Circuits Pro One

“This one is in excellent cosmetic condition and working 100%. It has just been serviced and with a lot of restoration. It is ready to be played and needs nothing! I doubt there is another here on Ebay that is as nice cosmetically and that has had the same amount of restoration. Please mail with any questions. Not sold as-is! California residents to pay state tax. Shipping to most countries!” Click here to search for synths on eBay

Sequential Circuits Pro One

“The Sequential Pro One is a wicked little monosynth! It comes from the same period and genre as the Roland SH-101 and Moog Prodigy. The Pro One was basically Sequential’s attempt at taking their legendary Prophet 5 poly-synth and packing it into a compact, inexpensive, monophonic analog synth! It has two VCOs, a great 4-pole lowpass filter, two ADSR envelopes (one for filter), and a compact three-octave keyboard. With a Pro-One, you can easily create punchy analog bass-lines and leads or quirky analog synth effects.

The Pro One is an extremely flexible synth with lots of modulation possibilities (ie: the filter, VCO B and LFO can modulate VCO A or B frequencies or pulse widths, or the VCF). There’s also an onboard sequencer, something common on many Sequential synths but not often found on other monosynths of the time. It is very basic, however, storing only two patterns and up to 40 notes max. Also, only pitch info is recorded (and in step time only); you can not assign a note duration to any notes. So it’s basically a short melodic sketch-pad…but useful. Also onboard is an arpeggiator which has UP and UP/DOWN patterns.

Unit has been pro repaired with a replaced key grommets & AC power cord. In perfect working condition with minor cosmetic issues due to age & handling.” Click here to search for synths on eBay

Sequential Circuits Pro One

“Vintage Sequential Circuits Pro-One analog synth. Recently serviced and fully cleaned by Takeshi at Main Drag Music in Brooklyn. Fully working J-Wire keyboard and several upgraded and restored pots, keyboard bushings and wiring. Unit is in AMAZING sonic, mechanical and cosmetic order and we are reluctant to part with it. We have a Prophet 5 so most of our vintage SCI sound is covered, but this unit takes CV and Clock I/O as well as External Audio, which is a big part of the way we work with synths. You can bring anything into this filter and control the filter CV externally!! Can route tons of modular gear through this and it BLOWS AWAY most of the modular. The keys on this unit are a joy to play and rock solid. The arpeggiator works along with, basically, a legato mode on the keys that plays at the same time, and can be set to either transpose or add notes. It is a great feature and there is tons of tweakability on this synth – which makes it very special and why prices are only going up right now. There is one piece of gaffer tape we put over part of the fuse box, as it is inherently a bit flimsy and having it prevents any issues from fuse popping out for any reason. ” Click here to search for synths on eBay

Sequential Circuits Pro One

“Sequential Circuits Pro-One, J-wire Keyboard, Recently Refurbished. Condition is “Seller refurbished”.

Had the bushings replaced, j-wire keyboard cleaned up, oscillators tuned and the power cord replaced. Everything else just needed to be cleaned off. The only noticeable damage is a few chips and dents in the wood siding.

I would certainly prefer local pickup as it is decently heavy and I would hate for it to be potentially damaged during shipping.” Click here to search for synths on eBay

Sequential Circuits Pro One

” Vintage Sequential Circuits Pro-One analog synth. Recently serviced and fully cleaned by Takeshi at Main Drag Music in Brooklyn. Fully working J-Wire keyboard and several upgraded and restored pots, keyboard bushings and wiring. Unit is in AMAZING sonic, mechanical and cosmetic order and we are reluctant to part with it. We have a Prophet 5 so most of our vintage SCI sound is covered, but this unit takes CV and Clock I/O as well as External Audio, which is a big part of the way we work with synths. You can bring anything into this filter and control the filter CV externally!! Can route tons of modular gear through this and it BLOWS AWAY most of the modular. The keys on this unit are a joy to play and rock solid. The arpeggiator works along with, basically, a legato mode on the keys that plays at the same time, and can be set to either transpose or add notes. It is a great feature and there is tons of tweakability on this synth – which makes it very special and why prices are only going up right now. There is one piece of gaffer tape we put over part of the fuse box, as it is inherently a bit flimsy and having it prevents any issues from fuse popping out for any reason. ” Click here to search for synths on eBay

Sequential Circuits Pro One

“Sequential Circuits Pro One Synth

Serial # 649. Original, not revision.

Serviced:

J-Wire Keybed, all new bushings, Keys and wires aligned…

New internal power connector, new ribbon cable
New high end Panasonic electrolytics
all switches and pots meticulously rinsed/cleaned/conditioned/sealed/lubed
PCB cleaned with 99.9% isopropyl
tuned and calibrated” Click here to search for synths on eBay

Sequential Circuits Pro One

“I am the original owner of this Pro-One. It’s in excellent condition. I had SynHouse MIDI installed in the late 90s. It has The more reliable & preferred 37-note J-wire style keyboard. Recently is was serviced/refurbished by vintage synth repair specialist John Paul Bohon of Double Heart Audio in Austin. You can see more of his work at SwitchedOn vintage synth shop in Austin. The synth and the MIDI work perfectly. The synth comes with its original user’s manual and SynHouse MIDI manual. Also included is a receipt for the recent work done.

The last picture is a picture of the holes above the pitch and mod wheels. In the left hole, just below the surface is a MIDI tuning slot. The right hole is a small button. It resets and changes the MIDI receiving channel. MIDI functionality is explained in the included Synhouse manual. They were installed with the MIDI installation.

The work done recently is listed on the receipt in the pictures. It includes repair MIDI functionality, replace the MIDI jack (I had a cleaner looking jack installed), replace/lubricate all keyboard bushings, repair four non-functioning keys.

Feel free to message me if you have any questions.” Click here to search for synths on eBay

Sequential Circuits Pro-One

“Synth was used by original owner (whom I am selling on behalf of) until the 90s and then stored until being brought out to test earlier this year. This synth has been used is 8/10 cosmetically. The serial number is 3898 meaning it has the more stable J wire keyboard rather than the later membrane type.

Recently repaired power supply and one broken key by Audio Circus, I have invoices showing this. While this synth does work well, it could do with a little more work to get this to factory spec. Those works have been recommended by Audio Circus. Keyboard re-bushing and pots cleaning, I have the quote for this work and I can arrange to get this done (buyer pays) if the buyer requires. This could be done before they receive the synth. It is essential you ask me about this.” Click here to search for synths on eBay

Sequential Circuits Pro One

“If you’re unfamiliar with this synth, it’s essentially a single voice version of the popular Prophet 5.

Just serviced by my tech, except I did not have him service the keyboard. The keyboard works, but could use rebushing or one of those Fatar drop-in replacement keyboards. Has two reproduction knobs.

This specimen is in pretty good condition for being around 40 years old. See photos of minor blemishes.” Click here to search for synths on eBay

Sequential Circuits Pro One

“Sequential Circuits Pro One. Needs a good home. Condition is Used. This is a very special synth and is in full working condition with a few minor cosmetic flaws.There are so many things that make this synth special. These two Curtis 3340 VCOs (that so many modern analogue synthesizers have tried to replicate) allow for thicker bass notes and richer, more colorful, piano like Mids. The modulation matrix is capable of adding even more to the Pro One’s sound including countless timbral possibilities through FM synthesis, up to two LFOs, and a filter envelope that can also modulate pulse width and oscillator frequency as well. The Pro One also has an additional VCA envelope, and both envelopes have a re-trigger mode. Oscillator B can serve as an LFO or audio rate modulation source, and can generate frequencies independent of the keyboard. It has a sequencer and arpeggiator as well. The serial number for this unit is right in the sweet spot where Pro Ones had good power supplies and keys. That said even the better of the two key beds will need to be occasionally serviced. These keys have recently been serviced and none stick currently. They will begin to stick over time though, and the key bed will need to be routinely cleaned. The keys are just a bit stiff, as is the nature of all Pro Ones.” Click here to search for synths on eBay

Sequential Circuits Pro One

” This is a Pro One analog monophonic synthesizer Packed with features and a ton of modulation routings. This keyboard has the earlier, more reliable J wire keyboard. It is in good working condition. I’ve owned and used this keyboard for many years, always keeping it in my home studio. I was disappointed to find that after a recent move, one sliding switch was knocked off. Although moveable with a pen, the switch should be replaced. This part is still available from Wine Country Productions for under $10. This damage is shown in one of the photos. Because of this damage, I am offering this synth for less than it is worth. Although I have tested and confirmed that all features and functions work, it is sold AS IS. This synth is about 37 years old and these synths do occasionally need service although the Pro Ones are some the most reliable synths I’ve owned. ” Click here to search for synths on eBay