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One
of the most important links in the recording chain is the microphone preamplifier,
and many engineers recognize that console preamps can often be bettered.
And the popularity of 8-track digital recorders has created a market for
mic pre’s that interface directly with MDMs, bypassing a console entirely.
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Marketed by Neumann
USA, the Precision 8 is an eight-channel microphone preamp manufactured
by True Systems, a product line of Tucson, Ariz.-based Sunrise Engineering
and Design, Inc.
In order to fit eight mic pre’s into a single rackspace, Sunrise
Engineering has eliminated some of the bells and whistles common to other
8-channel preamps, such as a summed output, a headphone amp or aux sends.
However, the Precision 8 offers a few handy features not found on other
units: The first two channels can function as an M/S decoder, and the
last two channels double as instrument direct boxes. The metering scheme
is well thought-out with peak hold and reset functions, as well as an
adjustable peak reference level.
Appearance
The sturdy enclosure has a thick front panel with nine knobs: eight for
input gain and one for selecting peak reference. The peak selector knob
is a stepped switch, while the gains are continuously variable. Every
gain knob is flanked by switches for polarity reverse and 48V phantom
power. An additional switch engages the M/S decoder on the direct outputs
of channels one and two. The switches feel solid, and the knobs have a
satisfying smoothness when turned. White lettering on a burgundy background
is easy enough to read, even in dimly lit environments and adds to the
handsome appearance of the unit.
Each channel has its own overload light and five-segment level meter.
On each meter, the first two green segments indicate signal present (anything
exceeding -24dBu) and the second lights up at +4dBu. The next two segments
are yellow and show when the signal is 6 dB and 3 dB below the level set
by the peak reference switch. The red fifth segment illuminates when the
selected peak reference is reached. The peak and overload LEDs remain
lit once illuminated; the Reset button clears all held peaks.
The back panel has eight XLR inputs (the DI inputs for channels seven
and eight are Neutrik Combo XLR/1¼4-inch jacks). Sixteen outputs
allow the Precision 8 to function as a splitter, with eight of the outputs
appearing on balanced 1¼4-inch jacks, and the other eight outputs
available through one DB25 (multipin) connector wired to the Tascam convention.
The rear panel also has a ground lift switch.
Contents
The instrument DIs are discrete FET designs, while the mic preamp is a
hybrid design which uses discrete, monolithic, dual bipolar transistors
for the input stage, followed by Burr-Brown IC op amps for the intermediate
stage and output driver. No transformers are employed, and there are almost
no capacitors (two are used for phantom power blocking). The result is
an extremely flat, uncolored signal.
Metering options are numerous. Resetting eight-internal jumpers (one for
each channel) switches the yellow -3 and -6 indicators to operate in peak-hold
mode.
The signal path of the M/S decoder is simple, using no extra buffering
or phase inversion circuitry. Both phases of channel one and channel two
signals are already available internally and are combined resistively
at the intermediate stages of the two channels. This causes the gain controls
of the two channels to interact when decoding M/S. For example, changing
the width also changes the output level, but I had no trouble achieving
the desired stereo image with proper output.
The stated specifications are impressive: Frequency response at 40dB of
gain is 1 to 500k Hz, +0/ -3dB, noise is rated at –132 dB EIN (20
to 30k Hz) and maximum output is +31dBu.
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Reprinted
with permission from 
Magazine, October, 2000
© 2000, Intertec Publishing, A Primedia Company All Rights Reserved
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