Based on the ZDT Preamp technology designed by David Blackmer, the 1 RU space 521 ZDT Single-Channel Mic Preamplifier from Earthworks brings the exacting standards of the Zero Distortion Technology preamplifiers to the convenient 500 series format.
The solid-state 521 ZDT Preamplifier features switchable phantom power, polarity invert, and peak amplitude clip detection. The transformerless output stage of the 521 ZDT preamplifier can easily drive long cable runs without loss of quality, making it suitable for remote recordings. Transparent gain is switchable from 5 to 60 dB in 5 dB steps.
The Earthworks microphone preamplifier topology provides strong common mode rejection, a high overload margin, and a low noise floor, combined with the wide bandwidth of the ZDT preamplifiers (1 Hz to 200 kHz +0.5 dB), and distortion of less than one part per million (0.0001%). This level of performance is maintained over an extensive range of impedances applied to the input, making the 521 ZDT preamplifier suitable for practically any microphone—ribbon, dynamic, or condenser.
Clean, uncolored 500 series preamplifier for standard 500 series racks (required; sold separately)
Zero distortion, less than 1 ppm (>0.0001%)
Solid state, transformerless
Switchable 48V phantom power
Polarity invert switch
Peak amplitude clip detection
Transparent gain switchable from 5 to 60 dB in 5 dB steps
High output level of +30 dBu
Fully differential (balanced) from input to output (i.e., no internal conversion to single-ended)
All discrete components; Class A amplification (no ICs and electrolytic capacitors in signal path)
Greater transparency with minimum signal path and features
Low noise floor
Suitable for most ribbon, dynamic, or condenser microphones
Earthworks 521 Specs
Type: Solid state
Number of Channels
2 Hz to 100 kHz ± 0.1 dB 1 Hz to 200 kHz ± 0.5 dB
XLR Out: less than 1 ppm (0.0001%) 1/4" Out: 0.001%