ART Pro Audio Pro Channel - Mic Preamp/Compressor/EQ - Manual (Page 7)

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Overview
Why use an external processing channel?
The best way to get a signal to tape is by using the shortest signal path. In most cases,
the shortest path is as follows: mic to preamp to compressor to EQ to tape. (The signal
doesn’t even go through a mixer!) This isn’t a new concept, but it has become more
relevant with the availability of affordable mixing consoles.
As their name implies, most affordable mixers are optimized for signal routing and
general level mixing. However, they are not necessarily your best option for the actual
recording of tracks. The simple truth is that the Pro Channel has a better sounding and
more flexible collection of circuits. Mixer manufacturers need to make tradeoffs
between price and performance. Imagine the price of your mixer if each channel’s EQ
cost over $200 (we’re not talking to those of you who have a $250,000+ console)! For
those of us on a budget, it just doesn’t make sense to spend a ton of money on a
“Cadillac” console when a budget mixer and a few pieces of external gear is more cost
effective. Even those engineers who regularly work on “big” consoles use external EQs,
compressors, and preamps!
The goal of any recording is to get the sounds right before you commit them to tape.
The Pro Channel helps you get it right so you don’t have to “fix it in the mix.”
Design Notes
The Pro Channel is a multi-purpose tool for audio engineering and recording. Enclosed
in a two rack space (2U) chassis are three independent circuits featuring a tube-based
analog preamplifier, a VCA-less compressor (selectable between optical or tube control
elements), and a semi-parametric, tube-based equalizer.
The Pro Channel is designed to work seamlessly with any recording, sound-
reinforcement, or electronic instrument setup. A R T’s Pro Channel circuitry is a hybrid
design utilizing the most advanced solid-state and tube technology. With a
transformerless power supply, the Pro Channel maintains exceptional signal integrity
and extremely low noise.
Signal flow within the Pro Channel is from the preamp, to the compressor, to the
equalizer (although you can change the order of the circuits by utilizing the insert
points). While the preamp is always active, the compressor and equalizer may be
individually bypassed. The preamplifier’s active, balanced, solid-state input provides
extremely low noise and excellent CMRR (Common Mode Rejection Ratio).
The ¼” input has a high impedance, which prevents the loading of any device connected
to it and makes the Pro Channel perfect for DI or line level applications. The
preamplifier’s second stage 12AX7a tube runs on a regulated DC voltage, providing an
additional 20dB of gain. Our design enables the tube to overload before the input or
output stage, allowing you to manipulate the tube gain to meet different sonic criteria.