CEM3394 Test

The CEM3394. A synth-on-a-chip, made by Curtis Electromusic Specialties, during the golden age of synthesizers.

The IC contains a VCO, VCF, VCA, a wave shaper, an external mixer and a cool sounding VCF modulator. Check out the datasheet for
a nice and tidy block diagram.

The CEM3394 was used in the Akai AX60, Sequential Circuits Six-Trax, MAX, Split8, and is still being used in the Doepfer Dark Energy.

Since I didn’t have much experience with op amps, this project became quite a challenge for me.
However, after some reading and simulation, I got around and did a PCB layout.

For pitch and gate CVs, I used the MIDImplant from Roman Sowa. Worked perfectly out of the box.

This slideshow requires JavaScript.

After populating the PCB, wiring the pots and hooking up the powersupply, I fed it with some MIDI from my computer and it actually did work
on the first try. Didn’t expect that. I tend to mess up the simplest circuits most of the time.

Audio demo:
Filter modulation, filter, waveforms and more

3 tracks with the 3394, and software drums.  A bit out of tune.

Here is the schematic. Please take a look at the red note..


3 thoughts on “CEM3394 Test

  1. Hi

    I came across a forum post from you on the web about using integrating thel CEM 3394 IC’S, I have pull out 6 of these from my not working Sequential Max keyboard.

    I would like to know if you have realize this project or if you can give me some info on how to make a simple synth with CV

    Where or how can I find or make PCB

    or maybe with an arduino??

    Any help is really appreciated.

    Best regards,


    Montreal Canada


  2. Six CEM3394s were used in Nolan Bushnell’s highly successful Sente arcade system. It was probably the only video game system to use programmable analog tone generators.


  3. Sounds fantastic! Makes me really miss my old AX60. I just came across a few cem3394 chips myself. Do you still have the PCB layout? If so it would be much appreciated.



Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s