Based on the Earthworks ZDT Zero Distortion Preamplifiers technology designed by David Blackmer, the 521 brings the exacting standards of the Earthworks Zero Distortion Technology preamplifiers to the convenient 500 series format.
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