Wersi Wersimatic CX2 Proto-Groovebox from 1984

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via this listing

The CX2 is a stereo, proto-groovebox that is part warm analog synth, part organ, part crunchy, punchy 12-bit sampled drums, all user programable with analog effects and auto-accompaniment. Not bad for 1984!!

Listing Includes:

Wersimatic CX2
Printed manual/assembly guide
Printed “Technical Document” (German)
User “Cheat-Sheet”
New CR2032 Battery

The CX2’s drum machine section consists of 54 preset rhytms, but it is also possible to compose your own rhytms by using its composer (static/real time composing) and the 20 different drum sounds available, plus it also has programable accents.

The accompaniment section has a bass (guitar, synth, tuba), chord (e-piano, guitar, wah guitar, strings, organ), and arpeggio section (brass, clarinet, banjo, bells, strings) which can be played solo or combined. When the drumsection plays the accompaniment section can be triggered and transposed via the 29 key keyboard. And best of all, you can also make your own custom bass, chords, and arpeggio patterns!


• 64 Preset Rhythm Patterns
• 48 Accompaniment patterns
• 16 User programmable (32 measure) patterns
• 1 “Super Sequence” (aka song)
• 3 Melodic Instruments (Bass, Chords, Arpeggio)
• 20 Programmable Drum sounds + 8 Manually Triggered Sounds (4 are working)
• Stereo/Mono outputs

This CX2 has the following voice cards installed…

• DDS1: 14 - 12-Bit PCM Digital Drum Samples
• WM54: Chords with SSM2044 (24dB/Oct Lowpass VCF IC)
• WM56: Bass/Arp with 2 x SSM2044 ICs

Aside from the following issues this CX2 is in fully working condition…

When no sounds are playing a low hum can be heard from the analog side (left) of the output. All capacitors in the power supply have been replaced but the hum persists. It’s definitely noticeable when nothing is playing, but hardly at all once you play a pattern.

4 of the manually triggered samples do not sound when triggered (“Aha”, “Ole”, “Hey” and “Whistle”). I believe this is because ICs 7 and 8 are missing on the internal DDS1 sample card

One of the 4 light bulbs does not light up. Note: I have disconnected the lights as they produce quite a lot of heat. No soldering required to reconnect them.

A connector that was meant to attach to a Wersi organ has been disconnected (done by the previous owner)
This unit uses 220v and requires a Step Up transformer to be used in the US. I am NOT including it in this listing as it weighs 6 lbs and could damage the CX2 if packed together. However, I have one available if the buyer would like to purchase separately

All accompaniment, and programming features are working as they should. Tuning is relatively stable for a device from this era. All synthesizer and organ sounds are functioning and all keys on the keyboard work. All LEDs light. All button contacts have been cleaned and are working, however a few of them require repeated pressing until contact is made.

Some history about this unit… This CX2 was not working when I originally bought it and was brought back to life by esteemed electronics guru Dave Brown of ModularSynthesis.com who rebuilt power supply, added a replaceable battery, replaced damaged components and returned the unit back to its original unmodified specs. Reverb doesn’t allow links, but if you search YouTube for 'Modular Synthesis Wersimatic CX2' [video above] you can watch a short video Dave made of this unit working.

Cosmetically, this CX2 is in very good shape for its age (see pictures). The front panel is especially clean, with its painted text in great condition. One small area under the Start/Stop button is slightly faded. The right alphanumeric display has some light scratches and the dual concentric knobs show some wear. The keys are straight and have only a few very tiny marks. The structure of the enclosure is solid. No delamination or warping like I have seen on other units. There is some normal wear to the edges of the enclosure and a few scratches. The worst being one on the top of the unit and one at the rear. A previous owner has drilled two holes in the top of the enclosure. Perhaps for a music stand? And the bottom of the unit has some paint missing.

I found the CX2’s manual to be somewhat lacking in clarity and have made a “cheat-sheet” (which I will include with the sale) to hopefully help decode the somewhat cryptic CX2‘s user interface. Once understood however, the CX2 is pretty straightforward to work with, especially considering all that it is capable of."