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All information in these pages is copyright (c) 1989-2003 by Roger Nichols. All rights reserved. Permission for personal reference only, and may not be reproduced by any method without written permission.


True Audio Systems Precision 8 Mic Preamp Review
By Roger Nichols


Mic preamps are hard to review because they just lie there and do nothing. They just take your microphone signal, amplify it up to some usable recording level so you can use up as many bits as possible and then you forget about them.

A few months ago I had the opportunity to use the new Precision 8 microphone preamp from True Audio Systems. The feature that interested me initially was the built-in instrument interface (on channels 7 and 8), or "direct box" that enabled you to plug an electric guitar or keyboard directly into the mic preamp without and additional box. A professional balanced microphone usually has an impedance matching requirement of around 150 ohms, while a guitar pickup or synthesizer requires an impedance match in the neighborhood of 10,000 ohms. The reason I mention this is because I often see synthesizers plugged directly into a mic preamp without a direct box, which causes a thin sounding instrument caused by impedance mismatch. The True Audio Precision mic preamp prevents such occurrences.

The next feature that I liked was eight mic preamps in a single rack space. It fits comfortably in my ProTools rack for direct recording from microphone to hard disk. There are five segment meters for each input on the front panel to monitor levels. There is a master control to set the clipping reference level to match the recording device you are feeding, and a separate phantom power switch for each mic preamp. Some condenser microphones with their own power supplies can become very noise when you are unable to turn off the phantom power at the mic preamp.

The input connections on the rear panel are XLR. Channels 7 and 8 will also accept 1/4" plugs for the direct instrument interface. The output connections are either 1/4" balanced phone plug or XLR connectors on a snake that is attached to the rear panel by a DB25 connector because there isn’t physically enough room for 8 additional output XLRs on a single space chassis.

The first project I used the eight-channel preamp on was drums for the Pancho Sanchez Band. The transient response was amazing and the crystal clarity was just what I was looking for. The sound of the True Audio mic preamp rivals that of microphone preamps costing three to five times as much money. The first two channels of the preamp are set up for M-S decoding. I used the M-S configuration for the drum overheads. I used a cardiod mic for the mid signal and a bi-directional (figure eight pattern) mic for the side signal. I could control the stereo spread of the overheads using the M-S controls on the front of the True Audio mic preamp.

The results I got with drum recording were so good that I used it for a Les McCann recording, a Robben Ford project, and a Brenda Russell recording. The drum sound on all of these recordings sparkled.

Not to be content with only a good drum sound, I powered up the True Audio mic preamp for a Tower of Power horn section. Wow! (can I say that in a family oriented magazine?) During playback the horn guys commented on the great horn sound and asked what kind of eq I was using. I said wasn’t using any eq at all. I was recording from microphone to True Audio mic preamp to digital machine, period. Everyone was impressed, including me. To check out the direct instrument feature I recorded Don Grusin’s synths on a couple of songs. The keyboard sounds were "perfect." No eq, just punch record and go.


Conclusion:

The only thing that I would like to see added to the True Audio mica preempts is detonated fades for mica level. When someone walks ups to my rack and says, "What’s this?" They inevitably bump a knob that I had just tweaked to perfection. Discounting that comment as a personal whim, I could find absolutely nothing wrong with the Precision 8. The twin-servo circuit design of the Precision 8 eliminates almost all of the capacitors in the audio path providing a frequency response of 1Hz to 500kHz. Distortion values are less than .008% and crosswalk between channels is less than –130dB. All in all, a nice piece of engineering.


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