Breathe New Life Into Your Mix

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
Wide bandwidth
Suitable for most ribbon, dynamic, or condenser microphones
  • Preamplifier Type: Solid state
  • Number of Channels 1
  • Frequency Response 2 Hz to 100 kHz ± 0.1 dB1 Hz to 200 kHz ± 0.5 dB
  • Impulse Response 1.4 µs
  • Distortion XLR Out: less than 1 ppm (0.0001%)1/4' Out: 0.001%
  • Input Noise 1.6 nV/Hz½ at 20 dB gain0.6 nV/Hz½ at 60 dB gain
  • EIN -132 dBV at 20 dB gain-143 dBV at 60 dB gain
  • Slew Rate 22 V/µs
  • Output DC Offset: ±1 mV typical, servo balanced
  • Input / Output Connectors 500 series EDAC Edge connector
  • Input Impedance XLR: 10 kΩ phantom on100 kΩ phantom off
  • Front Panel Balanced Out: 1/4' TRS XLR female, balanced, transformerless (variable)
  • Dimensions One 500 series rack space: 1.50 x 5.25 x 6.00' (38.10 x 133.35 x 152.40 mm)
  • MPN: 521
  • UPC: 827517317090

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In the unlikely event that you received a defective product, a wrong product, or damaged product, Audio MIDI Plus will replace it at no charge of any additional shipping cost. We will send you a prepaid label to return the item, and ship you a replacement. You will not incur any shipping charges. Please notify us of any of damaged, defective or misshipped products within 14 days.

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Carlsbad, CA 92010

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