The SSM2018T and SSM2118T represent continuing evolution of the Frey Operational Voltage Controlled Element (OVCE) topology that permits flexibility in the design of high performance volume control systems. Voltage (SSM2018T) and differential current (SSM2118T) output versions are of fered, both laser-trimmed for gain core symmetry and offset. As a result, the SSM2018T is the first professional audio quality VCA to offer trimless operation. The SSM2118T is ideal for low noise summing in large VCA based systems.