I/V converter

In order to solve the problems of sunken distortion and crossover distortion caused by switching distortion generated by quiescent current of a tail tube with a small operational amplifier and transient intermodulation distortion generated by a differential input stage transistor in a negative feedback out-of-control state caused by large loop depth negative feedback due to time delay generated bysignals of a main circuit in the operational amplifier, the invention provides an I/V converter which provides a circuit composed of discrete components. During the design of the circuit, each tube is enabled to work in a class A state, and the big-loop negative feedback is avoided, so there is no switching distortion and transient intermodulation distortion. Because a common-base circuit is directly adopted from an input stage, the circuit also has high conversion rate, wide frequency band and high signal-to-noise ratio, and the I/V converter comprises a PCM1794A DAC chip system. According to the circuit, Q1, Q2, (Q