Universal Audio 710 Twin-Finity Quick Pick Review

Universal Audio 710 Twin-Finity Microphone Preamplifier reviewed by EM writer David Franz in EM May 2009 issue
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The 710''s compact design makes it ideal for standalone or half-rackspace operation.

Universal Audio products have been the go-to preamps in my studio for some time. With UA's introduction of the model 710 Twin-Finity Mic/Line/Hi-Z Preamplifier ($799), I have a new favorite. Its unique design features both analog tube and solid-state preamps, and you can seamlessly blend them while maintaining phase alignment. This just may be the most sonically versatile preamp I've ever used.

The 710 looks sharp. Its silver metal case resembles the attractive Avalon U5 and M5, but the glow from the diamond-shaped VU meter in the middle of the unit adds warm distinction. Its 2U, half-rackspace design lends itself to rackmounting (rackmount kit included) or to standalone use (handle kit available separately).


The front panel has knobs for Gain, Level, and Blend, which are used in combination to dial in the exact sound you want. The Gain knob sets the input gain, and because it drives the transistor and tube circuitry, it has the most influence on the tone. The Level knob sets the master output volume, setting the amount of signal sent from the 710's rear-panel line output. Roll the Blend knob to the Trans side to utilize only the solid-state transistor preamp, roll it to the Tube side to utilize only the analog tube preamp, or set it anywhere in between to combine the phase-aligned transistor and tube sounds.

The 710 accepts mic, line, and Hi-Z instrument (DI) input. The mic and line inputs are on the rear panel, whereas the Hi-Z input is on the front. The front panel also sports a +48V phantom-power switch, a 15 dB Pad switch for lowering the mic input level (this has no effect on line input or Hi-Z signals), a Low Cut switch that applies a 75 Hz low-cut Bessel-type filter, and a polarity-reversal switch. The Mic/Line switch selects the input source unless something is connected to the Hi-Z input, which trumps the other inputs. As you'd expect, the meter function switch determines what is shown on the 710's VU meter. When switched to Output, the VU meter displays the output level. When switched to Drive, the VU meter shows the THD (total harmonic distortion) level after the Gain control but before the preamplifier circuitry. That lets you observe how hard the tube and solid-state preamps are being driven.


Under the hood, the solid-state preamp utilizes a transistor design that generates current feedback to create gain without distortion or any loss of sonic detail. This transimpedance design provides transparent amplification with very little coloration and a wide frequency response. The tube preamp design borrows as much from tube guitar amps as from tube mic-preamp circuitry. Its 12AX7 tube is located after the gain control pot, which enables a gentle transition from mild tube warmth to full-on, dirty, even-order harmonic distortion as you turn up the gain.

The art that you can create with this hybrid preamp testifies to the science inside. The variety of tones that it generates can make just about any mic sound special. Performances captured with tube mics have added clarity when run through the 710's solid-state side. Signals recorded with inexpensive dynamic mics have increased depth and warmth when routed through the 710's tube side.

I tested the 710 on a number of input sources — bass, acoustic guitar, male and female vocals, and electric guitar — and was impressed in every case. To hear some examples, check out Web Clips 1 and 2.

The 710 is more than just two preamps in one. The infinity symbol below the Blend knob is very fitting because you can get just about any preamp sound that you want from it. This preamp would be a terrific addition to any studio, especially a smaller-budget studio that could benefit from its sonic versatility.

Value (1 through 5): 4
Universal Audio