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Hello, I have a need to bring a signal into my circuit whilst preserving its fidelity as best as possible. It isn't audio, but it has the same sort of requirements as the very best audio might require, so an answer assuming an audio line input would be very useful; ie best noise and THD performance. If I don't have onerous common mode requirements, such as common mode outside the limits in the data sheet, is there really any reason not to use the instrumentation amplifier (INA2128) in preference to the audio differential receiver (INA2134)? Both datasheets refer to somewhat unrealistic source impedances of 0 for some of the test conditions, so it makes comparison tricky. Taking, as an example, the output noise voltage at 1kHz, the audio device quotes 52nV(sqrt(Hz)), whereas the instrumentation device for the same parameter quotes 8nV(sqrt(Hz)). Why would an audio engineer ever choose the audio device in place of the instrumentation amplifier with open gain resistor, especially if he was unsure of the source impedance of the input signal? Thanks for your time. Steve
