Given these details, you might expect the output stage to be transformer‑coupled, but in fact the Twin‑finity employs a monolithic (solid‑state) balanced output stage.Īs with my own Solo 110, the Twin‑finity has a dual gain‑stage arrangement, with separate gain and level controls. These are then summed back together via the centrally located Trans/Tube blend knob, which goes from all‑tube to all solid‑state, and covers all points in between. The input is split to drive separate, phase‑aligned tube and solid‑state gain stages. As the instrument input needs to offer a high input impedance, a discrete FET circuit is used, yielding an input impedance of 2.2MΩ. Unlike some low‑voltage tube preamps, the tube here runs at the full 310V in the expected class‑A configuration, and the input stage uses UA's trans-impedance input circuity, a current‑feedback arrangement that combines good phase coherence with a wide audio bandwidth. The term 'Twin‑finity' describes the device's tone‑blending abilities, which can be applied to both the mic/line preamp and the 'Hi‑Z' instrument DI. In fact it couldn't be, because additional design techniques had to be incorporated to ensure the two signal‑paths summed in‑phase, which is not a trivial task when combining two very different circuit topologies.

I know there are users out there who would want it to blend the Solo 610 and 110 sounds, but that's really not what the 710 is about. This 2U, half‑rack, all‑metal preamp is a single‑channel device that can accept mic, line or instrument signals, but although the name suggests that there might be elements of the Solo 610 in the tube side of the circuit, and perhaps a Solo 110 in the solid‑state side, there are aspects of this design that make it quite different from either, resulting in a unique tonal character. With the Twin‑finity 710, Universal Audio have attempted to satisfy both camps by creating a preamplifier that has both tube and solid‑state signal paths, and a means to blend them as required. It's also true that some types of music work best with one or the other, so the same engineer may use tube or solid‑state preamps for different jobs. There are those engineers who swear by tube preamps for their warmth and musicality, whereas others prefer the accuracy of a good solid‑state circuit. Which is best, tube or solid state? When it comes to investing in a preamp, that's a question you may no longer need to ask.

Universal audio 710