The Universal Audio Twin-Finity 710 preamp has gained itself a great reputation. The only complaint you ever seem to hear from owners and users is that they wished they had a pair or more to widen the possibilities and ranges of use.
The answer from Universal Audio comes in the form of the 4-710d ($2,499), with UA packing a 2U box with four Twin-Finity 710 microphone/ line preamplifiers with their solid-state and tube blending capabilities, along with an additional four line inputs, making eight inputs that can feed the eight channels of analog to digital conversion (16- or 24-bit). The four Twin-Finity 710 preamps also have a basic compressor based on the well-known and respected UA 1176, as well as a switchable insert point.
The four channels of 710 preamp each have balanced XLR I/O (mic and line levels on input), plus insert sends and returns on balanced TRS jacks. The eight AES/EBU outputs are delivered via a 25-pin TDIF DSub connection, plus two ADAT optical connectors. The ADAT optical sockets will simultaneously supply eight channels out at sample rates of 44.1 kHz or 48 kHz, or four each when sample rates increase (up to 192 kHz). On the front panel are four unbalanced Hi-Z instrument inputs with a JFET input for each of the four 710 Twin-Finity preamps.
Each of the preamps features a lit VU meter (showing output, gain reduction or tube drive) and a full complement of preamp controls. There are two input stages, one with UA’s solid-state trans-impedance design and the other a Class-A tube (12AX7) stage valve. Users can choose between these input stages or, more interestingly, blend them together for a wide range of sonic possibilities. The two input stages are very good in their own right. The solid-state stage is clean, crisp and delivers a good bit of bite, whereas the tube stage has all the lower harmonic distortion and smooth coloration so many find appealing. Varying the level of input drive and blending gives a truly flexible palette to draw from.
The addition of the 1176-based compressor on the 4-710d is a very welcome one, and I never found myself wishing for more control when it came to basic dynamic processing. You can also apply an analog limiter to the eight converter inputs. The converters on the Universal Audio 4-710d offer a good transparent conversion process that translated all of the blended sonic components well. The Universal Audio 4-710d is an example of what a manufacturer can produce with such a depth of experience to draw upon. This is an extremely well thought-out device...a fabulous, feature-rich package all in a 2U box.