Oberheim Electronics 4 Voice Analog Synthesizer
FOR SALE ON Ebay May 13 2026 seller MadScienceLab
https://www.ebay.com/itm/127831349854
Oberheim FVS-1 Four Voice Analog Synthesizer
Custom Built in Black Anodized Metal Case with Matching Keyboard
Built for the guitarist Ronnie Montrose in the late 70's
Sounds Great and In Amazing Condition
From my personal collection. I bought this 27 years ago from the keyboardist, Gary Hull, who played keyboard on 2 Montrose albums and also toured with him 1990-94. Gary also modified this Oberheim Four voice for Montrose to add sequencer functions. This Oberheim has 4 great sounding late 70's SEM Units and 2 later model Sequencer modules that are quantized, and output to 4 SEMs. A remote keyboard controlled by the Keyboard module allows spilts and 4 note polyphony and many options for control. A programmed Expressionist MIDI to CV interface is included so the four voice is also controllable polyphonically over MIDI.
The Four SEMs have been calibrated tuned and checked for complete noise free operation in 2026. The keyboard has been leveled and bushings replaced and plays perfectly. In 2026 the power module and output module were restored by Synth Smith, an analog repair specialist with over 30 years working on analog synths. I did not change much from what Montrose had done to this synthesizer. He was well known for his customization skills. I did add VCF controls and pots for all the SEMs so you can control from remote LFO's. The Programmer has never been connected in the Oberheim, since I have owned it. In 2026 the Programmer battery was replaced and testing reveled it does work, but is not wired, and wiring it would be a lot of new wiring.
INCLUDES:
Oberheim FVS-1 in Custom Metal Case xx x xx inches
49 Key Keyboard in Custom Metal Case
2 keyboard cables, power cable, Manual and Notes
MIDI to CV Rack Convertor Expressionist Programmed ($650 refund if not needed)
Hard Shell Pro Road Case for Main Unit
SHIPPING:
Buyer pays shipping of main unit in pro hard case. I will pay shipping of keyboard, cables, manual, and midi to cv interface. I prefer to hand deliver and setup if within 300 miles of San Jose California and will refund shipping.
sold by owner of siliconbreakdown synthesizer site
search siliconbreakdown 4 voice for more info, history, and pics
Main Features
- Oberheim FVS-1 installed in a Custom Anodized Black Metal case
- Bulit for Ronnie Montrose in late 1970’s
- Used in Gamma 3 studio work, live with Froom, and Montrose post Gamma
- Four Vintage SEM Modules, 3 dated 1979 one 1977
- Two MIni Sequencers, These are later models with quantitization
- Keyboard Module so 4 voice polyphony with lots of options
- Output Module provides stereo Output, pan per voice
- Three Patch Panels for lots of options and fun
- Custom Sequencer circuitry designed by Gary Hull for Ronnie. Adds footswitch control of start/stop and step as well as clock select. Also S&H and Noise Output for Seq1
- Custom circuitry by Riley Smith for CV control of all filters. Adds VCF filter global control and per row VCF control and pots for mixing
- Restored Programmer that has been tested good in 2026 but has never been wired to rest of unit
- Custom Professional Road Case to insure safe shipping
- MIDI to CV interface programmed to control the 4 voices
- Professionally packed to insure safe delivery
. The pdf file below has high resolution images so zoom in to see the amazing condition of this Oberheim. See below text for history of this Oberheim.
james@siliconbreakdown.com
Oberheim Custom 4 voice with two Sequencers and Patch Panel. This Four Voice Oberheim was custom built for Ronnie Montrose in 1979-1980, and used in the band Gamma and other Ronnie Montrose projects until early 1990's. The keyboard connects with the main unit with large grey cable at bottom left. The main unit is housed in a custom anodized black metal case that matches the keyboard. Stock 4 voice units are called Oberheim FVS-1
History Of this Oberheim 4 Voice
Please email james@siliconbreakdown.com if you have any info or sightings of this synth
1979-1980 Ronnie had this Oberheim 4 voice built in custom anodized black metal case with a black metal keyboard that connected with a custom keyboard extension cable. The original modules are believed to be from an existing Oberheim FVS-1
Age of SEM Modules - SEM 1 has date Oct 17 1977 stamped and no Serial # , other SEMs May 17 1979 SEM 2 serial # 100584 - SEM 3 #100630 -SEM4 #100606. (see pics of serial #'s below)
1982 I believe this Oberheim was used in the Gamma3 recordings. In interviews Froom said he used Oberheim SEM's to fatten up the sound of his other keyboards in the studio. Several reports say Gamma used Oberheim SEM units live but I have found no actual photos to verify this unit used live with Gamma, yet.
1983 Ronnie Montrose and Mitchell Froom played as a duo with Ronnie using this Oberheim 4 voice live at several concerts. Riley Smith saw him use this Oberheim 4 Voice at The Catalyst on May 25, 1983 Some of the other dates of this duo were Cotati (May 20), San Jose (May 30), and San Francisco (July 16).
1983-1984 Gary Hull, who also sees the Catalyst date in Santa Cruz, meets Ronnie Montrose. Gary works with Ronnie to help repair and modify his gear. Ronnie told him his vision for the Oberheim 4 Voice . He wanted to be able to step through the sequencer with a foot switch so he could solo over chord changes programmed into the two Oberheim sequencers. He built several custom sequencer additions and small circuit boards to achieve what Ronnie wanted. Gary said he also replaced several of the original SEM units with newer ones during this time frame.
199? Ronnie gives Oberheim 4 Voice to Gary Hull for payment for studio work. Gary Hull played keyboard on two releases by Ronnie Montrose, The Diva Station (1990) and Mutatis Mutandis (1991) He also played keyboard in two tours with Montrose in early 1990's and 1994
1998 Gary Hull sells Oberheim to James Gideon. James and Gary worked at E-mu Systems most of the 90's and also worked together at Universal Audio in the 2000's, and have been good friends for decades.
1999 Completes disassembly and cleaning, connectors, pots, jacks, etc. Some power Caps replaced
2010 Synth Smith complete tune up. Keyboard restored, bushings replaced, keyboard leveled
2018 Connector for keyboard to main module redesigned and built by Synth Smith
2023 New Jacks and pots with custom circuits by SynthSmith added to panels for control voltage to filters
2026 Restoration of Output and Power Modules. Programmer tested as working but no cabling was ever made to connect all functions. Complete testing and tuning by Synth Smith
The four SEMs. Oberheim Synthesizer Expander Modules