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B Y PA U L V N U K J R .
Earthworks ZDT 1022 Microphone Preamp
New Hampshire-based Earthworks is a microphone company famous for their über-clean and honest microphones. Yes, the ones with the small tapering bodies and itty bitty capsules that look very much like microphones of the measurement variety. If you have read any of my recent reviews of their products you will know that I typically refer to these high-definition mics as the “straight wire with gain” of the microphone world. Of course that phrase is typically attributed to microphone preamps and refers to designs where the sound from the microphone and source pass through the unit strongly and cleanly with as little coloration as possible. Interestingly, this month we look at a mic preamp from Earthworks, which the company claims is truly worthy of the “straight wire with gain” title, the ZDT 1022 Microphone Preamp. This isn’t a brand-new product, but it’s one that is worthy of our readers’ attention, and I had a very interesting time reviewing it. Here’s what I found. Zero distortion ZDT stands for Zero Distortion Technology and is Earthworks’ proprietary creation from the mind of their principal designer David Blackmer. To explain what the ZDT preamp is, I will start with Earthworks’ own definition: The ZDT is a “Class A bipolar input circuitry device”. Internally the ZDT starts with a balanced input that is connected to a symmetrical, balanced output. It is a completely differential design and places no transformers or electrolytic capacitors into its signal flow. Because of this design, any nonlinear distortion stays below 1 part per million (that’s one ten thousandth of a percent) even at full gain, and... ta dah! Zero Distortion Technology! The ZDT is designed to offer a wide yet flat frequency response of 1 Hz to 200 kHz (that’s not a typo, 200 kHz... just imagine that kind of frequency response in a microphone!), a slew rate of 22V/microsecond, a rise time of 0.27 microseconds, an impulse response of 1.4 microseconds, and an equivalent input noise of –132 dBV at 20 dB gain and -143 dBV at 60 dB gain. All of this in English translates to a super fast, ultra clean preamp that Earthworks claims to be one of the quietest on the market. I cannot argue with that conclusion, since in my tests the ZDT 1022 was indeed quieter than any other mic pre in my studio. The ZDT visually The ZDT family is made up of the half-rack singlechannel model 1021, the
RECORDING January 2013
The sound of utter precision
two-channel version 1022 (on review here), and the fourchannel 1024. The 1022 and 1024 are housed in a single rack space that is clean and utilitarian in design. They are dressed in a simple matte black finish with white labeling, and the only visual nod to their boutique status is in their uniquely styled knobs. Each channel has two knobs, a pair of LEDs, and 3 toggle switches. On the far left of the front panel is a +48 V phantom power switch with a yellow LED indicator. Below that is a polarity switch, and a switch labeled On or Standby. This is not a power switch; the unit powers on when plugged in. It’s intended to be used to mute the signal for switching mics, or to turn the signal off between takes or whenever else you might want to stop the pre from passing signal temporarily. Next up is a large input-gain knob; this is a 12-position stepped switch that goes from 5 dB to 60 dB in 5 dB steps. This is followed by a smaller matching variable output pot that can attenuate the signal from 0 down to –20 dB when turned counter clockwise. While this looks like your standard “pushthe-input-into-the-output” style of mic pre, it is not, and the output attenuation works only when used with a secondary 1/4" balanced output on the back of the unit. (See below.) Around the back each channel has a balanced XLR microphone input and its corresponding ZDT-balanced XLR output. The secondary 1/4" TRS balanced out is tied to the output attenuation knob on the front and is useful if you do need to pad the unit’s output down when used inline with additional outboard equipment such as dynamics processors or hardware eq, etc.. (Some early units went out with this output labeled as unbalanced, which has lead to some interesting internet discussions, but it is in fact balanced.)
Table of Contents for the Digital Edition of Recording - January 2013
Recording - January 2013
Table of Contents
2012 AES Convention Report.
Universal Audio Apollo.
ADAM Audio F5 and F7 Monitors.
Earthworks ZDT 1022 Mic Preamp.
Trident HG3 Close Field Monitoring System.
AKG K702 65th Anniversary Edition Headphones.
Grace Design m903 Reference Headphone Amplifier.
Monitors & Monitoring.
Lauten Atlantis FC-387 Condenser Microphone.
Recording Fundamentals. Chapter 13: Monitors Part 2.
PreSonus BlueTube DP V2.
Getting Into Your Head.
Shure SE215 Sound Isolating Earphones.
iOS Music Tools: Last-Minute Audio Gifts!
Sennheiser HD800 Headphones.
2012 Annual Index.
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Recording - January 2013 - Cover2
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Recording - January 2013 - Fade In.
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Recording - January 2013 - Table of Contents
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Recording - January 2013 - Talkback.
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Recording - January 2013 - 2012 AES Convention Report.
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Recording - January 2013 - Universal Audio Apollo.
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Recording - January 2013 - ADAM Audio F5 and F7 Monitors.
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Recording - January 2013 - Earthworks ZDT 1022 Mic Preamp.
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Recording - January 2013 - Trident HG3 Close Field Monitoring System.
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Recording - January 2013 - AKG K702 65th Anniversary Edition Headphones.
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Recording - January 2013 - Grace Design m903 Reference Headphone Amplifier.
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Recording - January 2013 - Monitors & Monitoring.
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Recording - January 2013 - Lauten Atlantis FC-387 Condenser Microphone.
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Recording - January 2013 - Recording Fundamentals. Chapter 13: Monitors Part 2.
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Recording - January 2013 - PreSonus BlueTube DP V2.
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Recording - January 2013 - Getting Into Your Head.
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Recording - January 2013 - Shure SE215 Sound Isolating Earphones.
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Recording - January 2013 - Readers’ Tapes.
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Recording - January 2013 - iOS Music Tools: Last-Minute Audio Gifts!
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Recording - January 2013 - Sennheiser HD800 Headphones.
Recording - January 2013 - Advertiser Index.
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Recording - January 2013 - 2012 Annual Index.
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Recording - January 2013 - Fade Out.
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