Earthworks 1024 Microphone Preamp
By Rich Tozzoli (rtozzoli@aol.com)

Four channels of Zero Distortion

The cutsheet for the Earthworks 1024 microphone preamp states that it's clean, it sounds clear, and it has gain. Well, without sounding non-original and repetitive, it is clean, it does sound clear, and it has gain - lots of it. It's almost that simple!

The 1024 is a four-channel, single-rackspace preamp from Earthworks Professional Audio Products, in Wilton, New Hampshire. Known primarily for their LAB series preamps and an expanding line of high-quality microphones, the 1024 is Earthworks first offering featuring their new Zero Distortion Technology (ZDT) tag. ZDT, according to Earthworks director of sales and marketing Eric Blackmer, is primarily two things - a standard of excellence and the beginning of a new series of products from the company. With under one part-per-million distortion at 10 volts, 2 Hz to 100 kHz frequency response, and very low noise of any kind, the preamp does provide exceptional specifications. The question is, how will those great specs translate to sound? I must admit, I was anxious to plug it in and have a listen.

The layout of the 1024 is straightforward and simple. The front panel is broken down into four identical sections, one per channel. Each of these features a large precision stepped gain knob, ranging from 5 to 60 dB of gain in 5 dB steps, that feeds the channel's XLR output connector. Next to that is a smaller continuously variable gain control knob that feeds the 1/4-inch TRS output. Each channel also has a cool clip indicator LED that's designed to warn you before the preamp actually clips. When reaching 90% of full output, the LED will flash momentarily. The farther you go beyond that threshold, the longer the LED will stay on. If you have a full-on clip, it will stay lit for one second. Below this Clip light is a 48-volt phantom power switch with LED indicator and a polarity reversal switch. There's also a very useful standby switch, which mutes the preamp output while the microphone remains phantom powered. Finally, the master power LED sits at the right side of the unit, but there's no power switch on the front or the back. Once you power up your AC, you're on.

The rear of the 1024 features four XLR balanced transformerless inputs, configured pin 2 hot. There are two different types of outputs on the 1024 per channel; the first is an XLR labeled "ZDT Balanced Stepped Out," while the other is a 1/4-inch TRS jack called "Variable Out." The variable 1/4-inch out is 6 dB lower than the XLR out (when set to 0 dB with the variable output knob) and was included to provide a feed for unbalanced gear. Simply stated, the stepped gain control feeds the XLR output, and the variable gain control feeds the TRS output. As you'd expect, the XLR out provides better specs, and is the recommended connector option. Earthworks noted that the primary gain structure, XLR input to stepped gain to XLR output, is an entirely differential balanced path - something not seen in many pieces of gear.

The day I received this preamp it went right to work. With a quick and easy setup, I began with a stereo track on a Ramirez flamenco guitar. The mics were a matched pair of Earthworks QTC-1 omnis, sent to Pro Tools at 48 kHz, 24-bit. Dialing up a quick level, both the artist (in his cans) and myself immediately noted the grandé, truly authentic sound of the instrument. The audio coming through the speakers was exactly the sound I heard standing in front of the guitar. The transients of a flamenco guitar track can be sharp and quick, but the 1024 handled them with ease. I lit up the clip LED often, as I tend to print as hot as possible, but no audible distortion came through.

Next, I tried some cymbal and percussion overdubs with a pair of GT AM Series tube mics and DPA omnis, and, again, I got clean, clear tracks with low noise levels. When using a preamp, those are fundamentally the qualities I seek, and the 1024 delivers the goods as advertised.

Next, it was upstate to the Clubhouse studios in Rhinebeck, New York for a surround session. The objective was a four-channel remiking of 16 individual passes of strings consisting of cellos, violas, and violins. Setting up two Hot House speakers and feeding the mix through a Sony DMX-R100 into the large live room, I was seeking a sense of clarity and distance from the originally close-miked section. I set up the 1024 directly in the room, and fed two close Earthworks TC-30K's into channels one and two, then two distant QTC1's to channels three and four. The XLR outputs were run directly to Pro Tools, again at 48 kHz/24-bit. Once more, the results were excellent, with crisp clean tracks that truly added a sense of warmth and depth to the multichannel mix. I drove the preamp gain hard, lighting up the LEDs often, but the output to Pro Tools never distorted. In this particular application, low noise was essential, and the 1024's fully differential path let me capture dynamic tracks without adding unwanted distortion.

Overall, the 1024 provides a truly uncolored sound. For those who seek a sonically pure, high-gain transparent signal path, this preamp is for you. I found the 1024 revealed the true characteristics of the microphones that were plugged into it, translating the instruments and environments perfectly. This four-channel, single rackspace preamp is sure to find a place in many mobile trucks and audiophile rigs, but its TRS outputs will make home enthusiasts happy as well.

One last note for those who don't require four channels: Earthworks plans to release a 1022 two-channel model ($2,000) in the fall.