Module description

A Dual Voltage Controlled Amplifier based on the CEM 3330 chip.

A true dual VCA with linear (10%/Volt) and exponential (9dB/Volt) control. Amplitude modulation from 0 to 100%. External control of gain on each channel. Accepts both AC and DC inputs. A 'STOP' facility is included allowing the VCA to be cut off sharply to ensure synchronisation with other units.

The original model 80-9 was replaced by the updated 80-9A 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 increased gain factor.

Construction information

• ETI August 1980 for 80-9 (906KB pdf file)
• PCB foil diagram for 80-9 (50KB gif file)
• Digisound document for 80-9A (1.1MB pdf file)
• PCB foil diagram for 80-9A (50KB gif file)
• PCB size (mm) 160 x 95

Front panel designs

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

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