The 2180 VCA Tile uses a socketed That Corp. 2180BL08-U (0.02% THD) Blackmer Voltage Controlled Amplifier. The VCA is AC coupled with a -3dB frequency response of less than 0.5Hz to greater than 100kHz. The control response is exponential with 0V as off (approx -75dB attenuation) and +5V as unity gain. Control voltages greater than +5 will generate positive gain. Saturation will occur when the output attempts to exceed around 20Vpp.