Module description

A Voltage Controlled Mixer based on the CEM 3330 chip.

A four channel mixer with manual and external voltage control of signal mixing and panning. Frequency response from 0Hz to 18kHz. Manual control of overall gain with overload indication. Gain variable from -16 to +14dB. This unit offers many novel approaches to sound synthesis.

The original 80-4 model was replaced by the 80-4A incorporating minor improvements to the circuitry. The linear control compensation for the drive of the CEM 3330 was improved, together with a few component upgrades to reduce CV feed through and increase gain factor.

Construction information

• ETI March 1980 for 80-4 (2.7MB pdf file)
  Note: the original ETI article covers both the 80-4 VCM and the 80-5 Processor
• PCB foil diagram for 80-4 (60KB gif file)
• Digisound document for 80-4A (1.4MB pdf file)
• PCB foil diagram for 80-4A (xKB gif file)
• PCB size (mm) 160 x 97

Front panel designs

• Original 9 x 3 inch (3KB fpd file)
• MOTM-format 5U x 2U (3KB fpd file)

For more Digisound-related documents, please refer to the Other Digisound documents page.