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Instrument Registry: Model 1633 (Expander)

If the numbering scheme for this model is the same as the Chroma, the 1633 would have been manufactured for the North American market, like the 2103.


Igor Kovalev

"Purchased from Mark Smith (living in Broken Arrow, OK., USA) in October 2001." Recorded as model 1633 although it was reported as "0001" as it was from North America and presumably the same Mark Smith who worked on the Chroma team. See Chroma 21030437. [March 2005]

Thanks to David Clarke [21030085++] for forwarding this information.

Bob Wilson

"At one point in time I owned 0001 Expander. The Expander was traded to the guy in California that made Chroma to Midi interfaces." [March 2000] See Chroma 210?0046 for Bob's memories of working in the Gulbransen plant that produced the Chroma.


John S. Allen writes, "Doesn't boot up correctly. Working with the owner in a project that involves restoring and using [this and 16330016]." [August 2012]


Richard R

From warranty card info returned to Fender.

Justin Lewis

"I have owned it since 1996 when I bought from a Chroma tech in the Baltimore area." [March 2008]

"I installed CC+ (with breakout) and Luca's power supply replacement. Knock on wood, I have never had an issue with that unit since I bought it used in the mid 90s and I still intend on being buried with it." [January 2011]

See also 21030062, 21030671, 21030793


Claes von Heijne

"My Expander was bought secondhand 18 months ago from Toronto, Canada. It has serial 16330008 from what I can read, and has a Syntech interface. The Expander is rare; I have seen Herbie Hancock and Joe Zawinul use them live, and I have seen the one I bought. The ad I hanged on to is the only one I have ever seen. When I have the same patch in both Chromas, they sound slightly different from each other, my expander is thinner and cleaner, their filters must be little differently tuned." [September 1999] See also Chroma 21030290.


Lance O

From warranty card info returned to Fender.


David Clarke

"Purchased in Feb. 2002 from Ken Bonebrake (this is the Expander listed in Ken's posting [Chromas for sale] as the one '...with 8 non-working sound cards.'). Ken B. said this unit was purchased (by him) around the time they were discontinued. Ken further noted that approximately eight years ago the Expander simply didn't power up anymore and so it was dropped off at a music store to be repaired. It languished at the store (apparently in a back room just gathering dust) up until Christmas 2001, when it was retrieved - along other Chroma gear.

"As it sits today, the Expander is missing a couple LEDs, has a broken cable between the CPU and I/O boards, has 8 non-functional dual-channel cards and has obvious damage to some components in the PSU (including add ons/hacks/mods).

"It seems that the Expander may have had an affair with a Chroma while at the store as the current power supply (although an original Chroma supply) is not the original one for the Expander. The one currently installed apparently came from a Chroma (the serial number tag on it reads 21030936).

"This unit is also notable in that the I/O board is one which has the separate EOC modification on it, per Field Change Notice FCN2-004. (This is the first one of these that I've seen installed ... it's quite an ugly mod - as are the other mods for FCN2-005, etc).

"My intent will be to restore the unit." [March 2002]

"Unit fully restored and functional." [July 2002]

David also owns Chromas 21010259, 21030085, 21030421; and Expander 16330034.


John S. Allen writes, "working." [August 2012] See 16330003.


True Assoc. Foundation

From warranty card info returned to Fender.


Mark R. David

"I have Chroma #21030170, and Expander #16330023. I picked them up at a going-out-of-business auction from Atari in Cambridge, MA. I got them somewhere around 1983, I think and they were in fine condition then. Since then I've gotten foam-rot, so they don't look so hot - but I'm not that concerned about the cosmetics. The Expander has at least two voice boards that need work, and the power supply is kaput. The project hasn't made any progress for 10 months now, as work has picked up. Someday..." [September 2001] See Mark's A Windows Interface for the Rhodes Chroma.


Brian Silva

"I have 1 Rhodes Chroma, serial # 21030450 and 2 Expander modules. One expander is serial number 0110 and the other is 16330026. I live in Gloucester, MA, oddly enough only 20 minutes from the original factory in Waltham. Oh well, that ship sailed a long time ago." [October 2004]


Anthony B

From warranty card info returned to Fender.

Riccardo Grotto

"My synth collection comprises 4 Chromas: 2 keyboards and 2 expanders. The keyboards have these serial numbers: 21010249 and 21010252. But one is the one whose picture is in Martin Newcomb's book Museum of Synthesizers Technology. This one has been recently serviced. The other one [16330038] has the wood assembly painted black (for stage purposes?) and has MIDI. Frankly speaking I never opened it to see what kind of MIDI has been installed." [January 2002]

"For you information, the power supply of the two expanders which are 1633's are provided with a 110/120V switch. Maybe the 1633 models originally were intended for North American sale, but luckily they should have thought 'oh well, you never know how long or far it will travel. Put a voltage switch on it.' Arp's history has not so many wise thoughts like this one!" [October 2006]


James E. Whitsitt

From warranty card info returned to Fender.

Michael Krewitsky, ProSound Inc.

"Bought from the late composer James Whitsitt in the late 90's (he bought it new, I believe)." [February 2009] See Chroma 21030504.


Awakening Prod. Inc.

From warranty card info returned to Fender.

David Clarke

"Purchased in August 2000 from Nashville, Tenn. (The unit originally came from LA.) It came with a volume pedal, a footswitch and a JL Cooper 'ChromaFace' midi interface. Two voice cards needed some rework and a cap controlling the 'Power OK' signal in the power supply had to be replaced - but aside from that, the expander was in good electrical and mechnical shape." [February 2001]

David also owns Chromas 21010259, 21030085, 21030421; and Expander 16330012.


Stephen Grom

From warranty card info returned to Fender. See Chroma 21030502.

Dan Levin

See also 21030509, 21030821, 21030837. [July 2010]


Bruce K

From warranty card info returned to Fender. This is the same owner listed for 21030541.

James Coplin

"I have Expander 16330036. It is currently in Minneapolis and has passed through at least 3 owners prior to me getting it. I've had it for 10 years or so. The previous 2 owners were in Minneapolis as well.

"I bought it from Rob Williams who bought it from a local tech whose name escapes me at the moment even though he did a ton of work for me in the distant past. Rob had the synth for only a year or so and the prior owner had had it for a 'significant' amount of time. He had a thing for Chromas and had several.

"The aforementioned tech did a little modification with it. Mainly replacing the internal battery with a larger more long lifed version and moved it away from any circuitry to avoid death from leaks. He also built in a [Chroma Cult] interface. I currently have the new CPU board upgrade and I am waiting for the power supply upgrade before installing it. It is currently fully functionally with a little dodginess that I have run down to the power supply so hopefully a new power supply will put it back at 100%.

"I plan to give the unit a complete overhaul like I did a few years back with my Memorymoog. I plan to replace all trimmers, internal cabling, chip sockets and all headers with gold versions, and replace all the electrolytics. This with the new supply and cpu board ought to keep it kicking along for a few more years." [March 2008]

See Chroma Lives! (July 2008) for an update on this instrument from James. See also 21030850.


John Leimseider, Cantos Music Foundation

Donated by Ralph Grierson. [December 2003]

See also Chromas 21030434, 21030676, Expander 16330129


Riccardo Grotto

"I just opened the other expander to install the CC+." [October 2006] See also Chromas 21010249 and 21010252; and Expander 16330027.


Von C

From warranty card info returned to Fender.


Malcolm S

From warranty card info returned to Fender.


Kerry L

From warranty card info returned to Fender.


Mirko Lüthge

"I am owner of a Chroma (s/n 21010245) and of the Expander. I also own some special instruments of Klaus Schulze and Tangerine Dream)." [June 2002]



Jeff Bova

"After my stint with Herbie, I bought Chroma #2 and Expander from Lou Garisto a noted Composer/arranger in New York who I worked for doing Jingles when I was not on tour." (See also Chromas 21030407, 21030446, 21030457) [October 2001]


Peter Carss

David Clarke [21030085++] did some work on this Expander and writes, "It looks like the chassis itself my have been originally intended for a different serial number, as in addition to the handwritten '0101 on the inside, you can still make out where the factory had written 16310008, and then scratched it out and put 16330101 instead. When received, the Expander had been slightly modified to add two more 1/4 inch jacks and a toggle switch to the rear panel. The switch allowed the 'pedal 1' and 'pedal 2' control inputs to either come from the original Volume/Effects jacks or from the added 1/4 inch jacks (with a different voltage scaling). (At Peter's request, the jacks and switch was removed). When received, the CPU and I/O boards were set up as if the board was a Chroma (i.e., the EPROMs were for a keyboard-version and the I/O board was fitted with a key scanning processor and EPROM). Before going back to Peter, proper Expander firmware was put in, and the unnecessary keyboard chips removed from their sockets." [June 2005] "After [David] has overhauled it, there is a sale pending to one of the members on the Chroma [list], who was looking for one" See ChromaTalk post "Newby." [May 2005]


For sale on eBay in September 2003. [September 2003]

David Kronemyer, California, USA

"Recently bought in a private sale. Powers up but (so far) doesn't play; I may not have the interconnect cable done quite right, I'm still working on it. It doesn't show any visible damage and it may just be a matter of something loose inside." See also Chroma 21030200. [December 2006]


Eric W. Mattei

"I bought my Expander new in October 1983 from Sam Ash for $3150.00. Full price!" See Chroma 21030443 for more info. [February 2011]


Keith "Plex" Barnhart, The Music Plex

Keith was in touch in March 2009. He sold both his Chroma (21030112) and this Expander. See his entry in the Discography.

Tom Hughes, For Musicians Only

"I just acquired a non-functioning Chroma Expander. I'll write you the details on that when I get a chance." [April 2009]

See also Chroma 21030251.


Brian Silva

See Expander 16330026 and Chroma 21030450.


Wayne Griffin

Wayne reported buying this Expander in May 2004: see Chroma Expander D.O.A..


Mark W. Heckert

See Chroma 210?0928. This Expander is/was for sale. [January 2003]



For sale on eBay, June 2008 (item #250258976999). See Expander on eBay.


Ralph Skelton, Pacific Innovative Electronics

For sale and sold in 2011. "I bought this Chroma Expander in either 1986 or 1987 directly from Fender to use as a backup and programming synth when I was working with Josef Zawinul in all technical capacities." See also 21010150, 21030423.


Rob Belcher

"It came with last generation Syntech midi interface and original power supply. I paid £3500 for it. I'm probably going to add CC+ and a new power supply to it next year." [November 2014]

Rob previously owned Chroma 21030095 and Expander 16310012.


Rhett Lawrence

"I just got in and repaired a Chroma SN [21030023] and Expander SN (1633) 0125. They are owned by keyboardist/producer/songwriter Rhett Lawrence, from LA. His most recent well known work is the Kelly Clarkson album." -- John Leimseider, Cantos Music Foundation [November 2004]


Tom Moravansky

"I had Chroma Expander Serial #16330127 and recently sold it to an ARP enthusiast." [May 2002]

Mike Jaynes

"I now have expander serial number 16330127 that came from Jeffrey Koepper. This unit is in very good physical condition, but is currently not operational. Should be working soon with a new CC+ CPU." [March 2007]


John Leimseider

"I bought the Expander from Fender for $700 when they were dumping them. I also got 8 extra voice cards with the Expander when it turned out I has several bad cards. It was cheaper for Fender than having me fix it under warranty." [December 2003]

See also Chromas 21030434, 21030676, Expander 16330037.


Dave Bradley

"My expander is apparently one of the last ones; below is the history from John Butler, original owner and former Syntech employee." [February 2001] For a picture, see Dave's Keyboard and Synth Gallery.

John Butler

"How much did I pay for it? Don't hate me, please... I paid nothing. And it wasn't even stolen property. It was sheer dumb luck - right place, right time. Here's the story: Ken Yparilla was at that time making low-cost Midi lighting consoles for Fender. I was making some extra cash working for Ken assembling the things with him in his small warehouse in Simi Valley. One day I went with him to the Fender warehouse where he had to meet with a guy named Steve Grom, who I think was the head of the division that had anything to do with keyboards, midi, etc. After they did their thing, we were walking down an aisle in the warehouse and Steve said, 'oh, by the way, there's a couple of old Chroma Expanders sitting here if you want them - otherwise we're just going to throw them away.' (Seriously, Dave...throw them away!) That's how I got into one. I always thought it was a cool synth, but I had no idea I was getting something that would be a part of synth history and have value as such. Musically, I used it on probably 5 or 10 cues I composed for the show RealTV. I used it a lot in the 80's doing rock gigs in Sunset Blvd. clubs like The Roxy, The Whiskey, etc. when fat analog chords were hip."


Steve Grom

For sale in November 2009.

Nobuya Tanaka, Tokyo

[July 2011]


John O. Senior, Elm Street Studios

See Chroma 21030640.