The SSI2164 is a versatile VCA building block for high-performance audio applications. Four independent channels provide voltage control of current-mode inputs and outputs for a gain range from +20dB to –100dB, with control provided by a ground-referenced –33mV/dB constant. The SSI2164 will directly retrofit existing SSM/V2164 positions while offering improvements that include significantly lower overall distortion, on-chip protection against asymmetrical power failure, and a substantial increase of input current handling. The device offers considerable flexibility for a wide range of design goals and applications. A unique mode control allows selection of Class A, Class AB, or in-between using a single resistor. In addition, improved current handling allows use of considerably lower value input resistors for reduced output noise without loss of headroom. Two or more channels can be parallel-connected for further noise improvement. Finally, SSI2164 VCA channels can be used as high-quality OTA building blocks for a variety of applications such as voltage controlled filters, exponential generators, and antilog converters.The SSI2164 will operate on supplies as low as +8V for battery powered devices such as guitar pedals, or up to ±18V in systems where maximum headroom is desired.