Owner's manual

The Technical Stuff
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Model 710 Overview
The Universal Audio 710 Twin-Finity Mic/Line/Hi-Z Preamplifier combines our highly revered analog
tube and solid state preamplification technology... but with a twist. Its unique phase-aligned Blend
control allows the user to literally dial in the desired sound, from precise ultra-clean solid state tones
to fat tube presence and overdriven crunch, or anywhere in between.
Other features include a discrete JFET Direct Inject input (which allows for the direct connection of an
electric guitar or bass, or any instrument with a magnetic or acoustic transducer pickup); a monolithic
balanced output stage; +70dB of gain; +48V power and a -15dB pad for the mic input; phase invert
and 75Hz low cut filter; output and “Drive” (input) VU metering; a universal auto-sensing internal
power supply that allows for operation at any voltage between 100 and 240VAC; and a portable, rack-
mountable design for studio, desktop or stage.
710 Vacuum Tube Preamp
The 710 high voltage (310VDC) Class-A tube preamp section is based upon both classic guitar
amplifier design and classic tube mic preamp design. The circuit utilizes a 12AX7 tube for warmth and
roundness and is the second gain stage, located downstream from the Gain control pot, allowing the
circuitry to be overdriven by the first stage into anything from mild harmonic distortion to all-out
grunge; however, the transition to tube saturation is extremely gentle. The result is the gradual onset
of harmonic overdrive—no hard clipping here. As an example, the transition from 1% THD to 4% THD
occurs over a 14dB range. Because of its multiple gain stages, with a Gain control pot between them
(as well as a Drive Meter that displays the signal level entering the second stage), a wide variety of
tonal possibilities can be dialed in, from gentle warmth to extreme grit.
710 Solid-State Preamp
The 710 solid-state preamp circuitry utilizes Universal Audio’s transimpedance design for precision
sound and ultra-low distortion, delivering the highest possible quality of signal from input to output.
The term “transimpedance” refers to transistor configurations that employ current feedback to provide
gain and distortion immunity without the loss of sonic detail or musicality. Designed for applications
requiring the ultimate in transparent amplification with little or no coloration, its razor flat and
immensely wide frequency response yields highly accurate results and minimizes artifacts on the way
to the recording medium.
Noise and distortion are kept to near-theoretical minimums so critical signals may be generously
amplified without degrading the quality or character of the sound source. Zero-coloration preamps
such as these are especially useful for capturing the sound source with its original qualities and
character so that later processing may occur with maximum flexibility. There are no transformers,
tubes, compressors, or limiters in the preamp signal path—all technologies that provide useful
benefits, but which may add permanent audio coloration. For many users, the useful characteristics of
these devices are preferred at the mix stage—and are commonly implemented using DSP processors
and plug-ins with excellent (and reversible) results, such as those found on Universal Audio’s UAD
plug-in platform.