Vintage ARP 1613 & Mk II 1623 Sequencers w/ New Sliders

1613 via this eBay listing, also on Reverb

"The vintage ARP Sequencer is an exceptionally flexible analog step sequencer, offering independent control of two 16-step rows for complex patterns, modulation, and real-time performance tweaks. Renowned for its versatility, it can drive multiple synths, modulate parameters, or create evolving textures—making it a powerful centerpiece for any vintage or modular setup.

This is the real deal, a genuine vintage ARP sequencer, not a clone or remake! The sequencer is in very good physical condition and has just been serviced by ARP expert Synthchaser in October 2025. Work done included:

Synthchaser Precision slider upgrade. New, smooth, high precision Bourns sliders. The difference in the way these sliders feel and perform compared to the originals is a huge improvement.
Synthchaser replacement pushbutton switches - All new pushbutton switches -- the original switch caps are still installed so it looks the same from the outside.
Recapped all polarized capacitors - including power supply and all tantalum capacitors
New nuts and washers
Calibrated to factory spec

The ARP Sequencer has Tini-D jacks (like the ARP 2600 and other vintage ARP gear), which are slightly larger than 3.5mm patch cords. 3.5mm patch cords will still work, but for the best connection it's advised to use Tini-D patch cords."

1623 via this eBay listing, also on Reverb

The vintage ARP Sequencer is an exceptionally flexible analog step sequencer, offering independent control of two 16-step rows for complex patterns, modulation, and real-time performance tweaks. Renowned for its versatility, it can drive multiple synths, modulate parameters, or create evolving textures—making it a powerful centerpiece for any vintage or modular setup.

This is the real deal, a genuine vintage ARP sequencer, not a clone or remake! A real Mk II Black & Orange ARP Sequencer is rare! The sequencer is in excellent physical condition and has just been serviced by ARP expert Synthchaser in October 2025. Work done included:

Synthchaser Precision slider upgrade. New, smooth, high precision Bourns sliders. The difference in the way these sliders feel and perform compared to the originals is a huge improvement.
Recapped all polarized capacitors - including power supply and all tantalum capacitors
Calibrated to factory spec
The ARP Sequencer has Tini-D jacks (like the ARP 2600 and other vintage ARP gear), which are slightly larger than 3.5mm patch cords. 3.5mm patch cords will still work, but for the best connection it's advised to use Tini-D patch cords.

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Serviced ARP Omni 2 Synthesizer Keyboard with New Sliders & Anvil Case

Note: links to listings are affiliate links for which the site may be compensated.

via this Reverb listing, also on eBay

"The ARP Omni-2 is a lush vintage string and polysynth famed for its rich ensemble chorus and analog bass section, delivering the signature 70s sound heard on countless classic records. With fully polyphonic strings, synth layers, and classic ARP warmth, it’s a must-have for anyone chasing authentic retro textures and atmosphere.

This synthesizer is in good physical condition and has just been serviced by Synthchaser in October 2025. Work done included:

Synthchaser Precision LED slider upgrade. New, smooth, high precision LED illuminated Bourns sliders. The difference in the way these sliders feel and perform compared to the originals is a huge improvement.

Recapped all polarized capacitors - including power supply and all tantalum capacitors

4075 Filter cutoff frequency correction

Keyboard refurbished - New key bushings installed, buss bar & key contacts cleaned and adjusted, keybed leveled, keys cleaned

Tuned & Calibrated"

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Vintage ARP Odyssey Mk I Black & Gold 2800 - Serviced w/ New Sliders SN 283036

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via this eBay listing

"This vintage ARP Odyssey has just been serviced in October 2025 by Synthchaser - recapped, new key bushings, all new precision sliders, tuned and calibrated, and sounding awesome! The Odyssey was ARP's answer to the Minimoog, a feature packed scaled down version of the legendary ARP 2600. This Odyssey features the 4023 filter, a very fat 2 pole filter.

Despite appearances, this black & gold Odyssey is a Mk I (Model 2800) ARP Odyssey with an original 4023 filter, and no gate/CV interface jacks. It's equivalent to the white ARPs of the era, and different from the more common Black & Gold Mk II Odyssey.

The synth is in excellent condition with minor marks on the case. Work just completed on the synth included:

Synthchaser Precision slider upgrade - All 34 of the old original sliders have been replaced with new, smooth, high precision sliders. The difference in the way these sliders feel and perform compared to the originals is a huge improvement. They are fitted with original style slider caps.
Power supply rebuilt - All tantalum and electrolytic capacitors in the power supply have been replaced, and high quality, high temperature 105 deg C capacitors have been used for the power supply filter capacitors.
All tantalum capacitors replaced - The tantalum capacitors in ARP synths are ticking time bombs. All tantalum capacitors in this synth (except those in the sealed 4023 filter module) have been replaced with electrolytics to help provide stable operation for years to come.
Keyboard rebuild - New key bushings installed, keys cleaned, bus bars removed and polished.
Oscilloscope calibration - Calibrated & tuned using oscilloscope and frequency counter.
· 1/4" output made High - ARPs of this era had an RCA jack as the high output and the 1/4" jack as the low output. As today RCA jacks are an inconvenience for most, the 1/4" jack has been made to a second high output."

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Oberheim DMX Factory MIDI & Memory Expansion + Anvil Case + Synthchaser Battery Eliminator

Note: links to listings are affiliate links for which the site may be compensated.

via this Reverb listing

"The Oberheim DMX is a legendary vintage drum machine known for its punchy, organic 8-bit sampled drum sounds that defined countless hit tracks of the 80s, from New Order to Run-D.M.C. With its iconic swing, individual outputs, and rock-solid build, it delivers the classic analog-meets-digital groove that modern gear can’t replicate.

This DMX is in great condition and includes the factory MIDI and Memory Expansion board. The "Play" button is black instead of the usual white. The DMX includes a flight case that's in good condition.

This DMX was serviced in September 2025 by Synthchaser. Sliders and pushbutton switches were cleaned, and the Synthchaser Battery Eliminator was installed, so songs and sequences are saved without the need for a battery that poses leakage risks and requires periodic changing by a synth tech."

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Serviced Sequential Circuits Pro One with Fatar Keybed, Original Box & Manual

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via this eBay listing, also on Reverb

"The Sequential Circuits Pro-One is a legendary monophonic analog synth prized for its fat bass, searing leads, and incredibly flexible modulation capabilities. Compact yet powerful, it delivers the iconic Prophet-series sound in a hands-on design that’s become a must-have for serious synth players and collectors.

This Pro One is in excellent condition. It includes the original shipping box (and if being shipped, this is the box it will ship to you in) and manual (which has some writing in it). This Pro One was serviced by Synthchaser in September 2025. Work done included:

Recapped all original tantalum capacitors
Replaced original unreliable membrane style keybed with Fatar keybed
Cleaned pots & switches
Tuned & calibrated"

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Oberheim DMX Voice Card w/Original Box #1 – Timbale

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video upload by Synthchaser

via this Reverb listing

"Tested working original Oberheim DMX voice card with the original box! ROM is labeled “Timbale”, please see short video clip below for a demo of this card installed in a DMX."

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Serviced ARP Pro Soloist Vintage Analog Synthesizer Keyboard

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via this eBay listing

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Vintage Oberheim Two Voice Synthesizer TVS-1 Repair - Synthchaser #175

video upload by Synthchaser

"In this edge-of-your-seat exciting installment of the Synthchaser synthesizer repair video series, your host Synthchaser undertakes the repair of a vintage Oberheim Two Voice Synthesizer that is suffering from a dead SEM (Synthesizer Expander Module, or 'voice')."

Oberheim OB-SX 4-Voice Synthesizer W/ MIDI & Controller SN 913511XP

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via this eBay listing

"Here is a great package for any analog synth lover. It starts with a 1980 Oberheim OB-SX 4 voice that was overhauled by Synthchaser about a year ago... Works like a dream, all voices pass autotune. Has the synth king eprom in it. 56 presets. Comes with Magic Box Midi Editor that connects to the "Computer" Interface on the back. Also comes with a Behringer Controller that has the OBSX template loaded already.. Plug it all up and you now have so many controls to edit the OBSX!!! Synthchaser calibrated th OBSX as well as installed new key bushings. All in all a modern re-do and stable synth to deliver some jaw dropping Obie pads, brass, strings, leads, basses and more! RARE to find a turn key package like this and priced low as well!"

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Two Vintage Moog Sonic Sixes

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video upload by Synthchaser

One via this Reverb listing, also on eBay

2nd via this Reverb listing, also on eBay

Descriptions follow.

1st Sonic Six: "The Moog Sonic Six is a rare, portable analog synthesizer with classic Moog tone and ladder filter, featuring dual VCOs, sample-and-hold, ring modulation, and a built-in speaker—all housed in a rugged suitcase-style design perfect for studio or stage. Its unique sound-shaping capabilities including X/Y modulation, and vintage character make it a prized collector’s piece and a powerful tool for experimental or classic analog synthesis. While this synthesizer is often offered by sellers at a "high on crack" price, I am pleased to offer this one for less than half of what some delusional synth dealers are trying to get for it.

The synthesizer is in good condition, but the original "Moog" logo sticker on the outside was peeled off. The power switch does not illuminate when the synthesizer is powered on. The synthesizer uses a standard IEC power cord, and one will be included. Please see photos.

This Moog Sonic Six has been serviced by Synthchaser in August 2025. Work done included:

Cleaned switches, pots and sliders
Refurbished keybed - new bushings, cleaned bus bars & contacts
Tuned & Calibrated Synthesizer"

2nd Sonic Six: "This vintage Moog Sonic Six Suitcase Analog Synthesizer powers on and makes sound, but is being offered as-is at a discount due to cosmetic and functional issues. The A, X, and Y oscillators and the Moog Ladder filter appear to be working. This can be a great opportunity for someone willing to put a little work in to get this rare synthesizer below market. The synth is being sold as-is for parts or repair, with no returns.

Please see this video showing the functional status of the synthesizer. : [video above]

Issues I noticed (you may find other issues, but the synthesizer is still being sold as-is with no returns):

Cosmetic: A power cord has been hardwired to this unit in place of the power inlet. The exterior of the case is in rough looking condition and some screws are missing and things feel loose. The synthesizer is missing all knobs and switch caps. Some of the keys are stained. 2 rubber feet are missing, so the case needs something behind it to stay open when in use.

Functional: Oscillator B appears to be dead. The ring modulator appears to not be working (perhaps due to oscillator B not working, ring mod was not tested with external input). Key contacts are dirty and not working well, bushings need to be replaced. The contour generator appears to be broken. The Contour/Pitch Control pot for the filter was replaced with a pot that doesn't extend fully through the panel, so you can't use it. Pots, sliders and switches need cleaning. Calibration needed."

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Oberheim DMX Factory MIDI & Memory Expansion

Note: links to listings are affiliate links for which the site may be compensated.

via this Reverb listing

"The Oberheim DMX is a legendary vintage drum machine known for its punchy, organic 8-bit sampled drum sounds that defined countless hit tracks of the 80s, from New Order to Run-D.M.C. With its iconic swing, individual outputs, and rock-solid build, it delivers the classic analog-meets-digital groove that modern gear can’t replicate.

This DMX is in great condition and includes factory the factory MIDI and Memory Expansion board.Please see the video below to hear the sounds that are installed as some of the stock sounds have been changed. (On Reverb, this video will appear at the end of the photos list)

This DMX was serviced in July 2025 by Synthchaser. Sliders and pushbutton switches were cleaned, and the Synthchaser Battery Eliminator was installed, so songs and sequences are saved without the need for a battery that poses leakage risks and requires periodic changing by a synth tech. (I left the original factory battery sticker on, but there is no battery)."

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Serviced ARP Quadra Synthesizer with MIDI & New Sliders

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via this Reverb listing

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Vintage ARP Odyssey Mk I White 2800 - Serviced w/ New Sliders

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video upload by Synthchaser

via this listing

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Vintage Moog Modular Synthesizer Repair - Synthchaser #167

video upload by Synthchaser

"In this video I troubleshoot a dead vintage Moog Modular Model 12 and bring it back to life with a 3 cent part!"

Vintage ARP 2600 Synthesizer w/ 3620 Duophonic Keyboard

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via this listing, also on eBay

"Really nice vintage Orange & Black late model ARP 2600 with the 3620 Duophonic keyboard. This particular synthesizer is in great shape and was on display at NAMM 2020. The keyboard controller was serviced by Synthchaser in 2020 and the main unit was tested and calibrated by Synthchaser in February 2025.

There are some scratchy sliders on the main unit, and the tolex inside the main unit's lid is coming up on one edge (can easily be re-glued). Includes an original style oval power cord."

Nice R2-D2 on screen.

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Arp Omni String Synthesizer w/ LED Sliders

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via this listing

"Arp Omni String Synthesizer. Fully working. I recapped all of the boards except the power supply because the power supply is outputing the correct voltages. All sliders have been replaced with lighted sliders and work smoothly. Synthchaser master oscillator module installed to insure good tuning. Power cord is missing the ground pin. This was a diy project, when got this it did not work at all. After the recap and replacement of sliders it now fully works and sounds good. The next owner can play it as is but may want to consider replacing the power cord, recapping the power supply and replacing the keybushings. Cosmetically this unit is nice. There are a few scratches from normal use and storage and some keys that have marks on them but nothing major."

Pics of the inside below.

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ARP 2600 Grey Meanie Synthesizer with Matching 3604 Keyboard - One of 34 Made!

Note: links to listings are affiliate links for which the site may be compensated.

via this listing, also on eBay

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Arp Quadra Serviced Keyboard Synthesizer

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via this listing

Additional Retro Gear Shop Listings

"Rare vintage Arp Quadra synthesizer keyboard that just got back from a full servicing by Synthchaser. Work included a complete re-cap, new slider pots (which can be led activated at a later stage if desired), new touch panel membrane and keybed refurb. It's fully functional and good to go. We have a long demo video made by Synthchaser we can share on request. The only issue worth mentioning is the lower transpose button is not working, but the upper transpose button does work and performs the same action. We have sold Arp Quadra's in the past for $12k - $15k and it's been a couple years since we last listed one for sale. These are very cool vintage analog synths."

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ARP QUADRA w/Synthchaser MIDI + LED upgrade + more

Note: links to listings are affiliate links for which the site may be compensated.

via this listing

"This synth has been fully serviced and upgraded, making it IMO the best and most musically usable Quadra you'll likely ever come across. Modifications installed are the Synthchaser Quadra MIDI kit (very few of these kits in existence, I believe there were only around 20 of them made/sold, and it is no longer available), the Synthchaser Quadra LED slider upgrade kit, as well as a custom modification which routes the external audio input through the Quadra's glorious stereo phase-shifter effect (normally the external input is simply there to mix in an external audio source, and isn't routed through any of the Quadra's processing signal path). For info on the Synthchaser kits, you can read up on them and watch video demos via their website: synthchaser [dot] com.

Additional notes:
(1) the Midi Out can alternately be switched to Midi Thru, via a switch on the board.
(2) I also had my tech install an on/off switch for the LED lights on the sliders, as seen in photo#9, under the "la tosca INC" sticker.

This thing sounds absolutely glorious, and everything, including keyboard aftertouch, is working perfectly. It was fully serviced at the same time as the Synthchaser kits were installed."

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Serviced ARP Omni 2 Synthesizer with Synthchaser MIDI Adapter

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via this listing

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