Universal Audio’s 710 Twin-Finity™ Tone-Blending Mic Preamplifier & DI Box is a radical UA mic preamp design that combines both the classic retro warmth of tubes with the transient bite of solid-state, all in a 2U, half-rack unit. In this article, we’ll share some helpful tips and tricks for how to get the most out of the 710.

Tube vs. Solid State — What’s the Difference?

Audio engineers tend to have both tube and solid-state preamplifiers at their disposal and choose between them based on the needs of the project. Tube preamplifiers have been long revered for their warmth and richness, while solid-state preamps provide a precise signal handling with meticulous attention to detail, definition and accuracy.

Commonly, solid-state preamps shine on classical or jazz recordings, which demand a faithful transfer of the performance without coloration, processing, noise, or distortion. Clean solid-state preamps also allow you to do the bulk of your sound sculpting and coloration decisions during the mixing stage instead of on input.

But if you’re aiming more for a “vibe” than accuracy, tube preamplifiers are well known for making most sounds larger than life by coloring the incoming signal in a way most listeners find pleasant and desirable.

So, which kind of preamp to use? Now with the 710 Twin-Finity, both designs are provided in one box. With its unique Blend control, you can dial in the precise contribution of each preamp to the overall sound.

Meet the 710 Twin-Finity

The 710 features dual gain-stage controls (Gain/Level), enabling you to radically vary the amount of coloration and distortion of the input signal. The VU meter features a unique Drive mode, so you can see how hard you are driving the tube/solid state stage. For more in-depth information on the design topology of the 710 Twin-Finity, we have a great Ask the Doctors article on the subject as well.

The 710 Twin-Finity preamp combines classic tube
warmth and the transient bite of solid-state.

Other features include a discrete JFET Direct Inject input for plugging in an electric guitar, or bass, or other instrument, a monolithic balanced output stage, phantom power, a -15 dB pad for the mic input, polarity invert, a 75 Hz low cut filter, and a portable, rack-mountable design..

For all its versatility and power, the 710 is remarkably easy to use. You’ll find that its controls are simple and essential, providing only those features required for practical use.

Let’s take a look at a few tips on how to get the most out of the UA 710 Twin-Finity preamp:

Drive Metering

The 710’s Tube preamplifier contributes precise amounts of even-order harmonic distortion to your signal, ranging from pleasant amounts of rasp to all-out grunge. The Drive meter function can be a great tool in helping to decide how high to raise the Gain control — it indicates how much tube saturation is going to be present in the output signal by monitoring the signal that is driving the tube.

If you want a crystal-clear tube tone, the meter will be bouncing near the low end of its range. If you are after a ton of tube dirt, drive the meter into the red —there is nothing wrong with either extreme. Once you use the Drive function a few times you will develop a feel for it and should be able to dial in the desired Tube character quickly and easily.

The drive meter indicates how much tube saturation
is going to be present in the output signal

When in Drive mode, the 710 meter is calibrated so that 0 VU is equal to 1.2% THD on a 1 kHz sine wave. However, measured distortion levels can be misleading since they are so source and style dependent. 2% THD on a sine wave is a fair amount of distortion and will be apparent to even the non-musically inclined. On a vocal track, however, that same 2% THD sounds like some really nice tube warmth. On an overdriven guitar, 2% is barely even audible.

The most important thing to remember when using the Drive function is that there is no “wrong” meter reading, only wrong tones for a particular track. So, use the meter as guide, not as a pass/fail test. Do what feels and sounds right, and don’t be afraid to push it.

Vocals, Vocals, Vocals

The presence of not just one, but two completely discrete preamps in the 710 means that it will work wonders with just about any microphone — and with just about any vocalist. Even an inexpensive stage dynamic microphone can come to life when routed through one or both 710 preamps, adding richness and airiness to the sound without adding undesirable graininess or coloration.

The crisp precision of a condenser microphone can be matched perfectly by the uncolored accuracy of the 710’s Transimpedance solid-state preamp. Or, you can instead opt to use the Tube side to “warm up” the tone. Better yet, use the center Blend control to dial in exactly the right amount of both preamps to match both the microphone’s frequency characteristics and the timbral quality of the vocalist.

The Blend knob opens up a whole
range of tonal possibilities.

If you’re using the already-warm sound of a tube microphone for vocals, try complementing it with the 710’s solid-state preamp. Or, use the Blend control to dial in a combination of Tube and Trans that favors the contribution of the solid-state Trans side.

Electric Guitar and Bass

It’s no surprise that tube amps are very prevalent in the guitar world — there’s something very special about the combination of tube preamps and electric guitar and bass. Cranking up the 710's Gain control will impart anything from a slight bark to total grunge. Set the Blend control all the way to Trans for that “overloaded console” effect, or all the way to Tube to emulate the grittiness and bite of an overdriven guitar amp.

Electric bass players may want to set the Blend control so that the Trans amp is slightly favored — try a 10 o’clock position to start. This will take advantage of the precision of the solid-state preamp stage and combine it with just a touch of tube warmth. For acoustic bass, try dialing in even  a bit more Tube preamp.

Acoustic Guitar

The 710 is also a powerful tool for the recording of acoustic guitar. Try pairing it with a small-diaphragm omnidirectional mic. Then, set the Blend to the 2 o’clock position  — slightly favoring the Tube preamp — for a sound that is both pristine and warm.

Horns and Reeds

The incredible detail provided by the 710’s Trans preamp makes it a perfect match for horn and reed instruments. Dial in the Blend control to approximately 9 o’clock to add a touch of tube warmth, and you’ve got a sound that will work in just about any musical context.

Drums

The 710 offers a huge range of sonic possibilities for drum recording. The excellent transient response of the Trans preamp easily picks up the crispness of cymbals from overhead and ambient mics, while the roundness of the Tube preamp adds fullness to snare and tom mics.

Make sure to experiment with the polarity
when using multiple mics.

Again, the best solution is usually a blend of the two, depending upon the position of the mics, and the specific mics being used. On that note, be sure also to experiment with the 710 polarity control whenever multiple mics are being used!

You can read even more about recording drums with the Twin-Finity series in this article: Exploring the Tonal Options of the 4-710d Mic Preamp on Drums

Live Applications

Although the 710 was designed primarily for use in recording, it can also serve as a powerful addition to a live sound rig. Because its Tube preamp section is based on vintage guitar amp design, it can even be used as an onstage preamp — just plug your instrument directly into its Hi-Z input and route the 710 output to a power amp or the front of house console input.

So, there you have it! Be sure to read the User Manual for the 710 to get the full rundown on all the details of this unique analog preamp, but hopefully this will get you started on some unique tonal explorations of your own.