The solid state 521 features switchable phantom power, polarity invert, and peak amplitude clip detection, just as in the original 1021 single channel ZDT Preamp. The transformerless output stage of 521 ZDT easily drive long cable runs without loss of quality, making it ideal for long cable runs. Transparent gain is switchable from 5dB to 60dB in 5dB steps. The Earthworks microphone preamplifier topology provides outstanding common mode rejection, excellent overload margin and an incredibly low noise floor, combined with the ultra wide bandwidth of the ZDT Preamps and distortion of less than 1 part per million. This exceptional level of performance is maintained over an extensive range of impedances applied to the input making the 521 suitable for practically any microphone – ribbon, dynamic or condenser.