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Field Test: Universal Audio Solo 610/110 Mic Pre/DI


Solo 610

Since 1999, Universal Audio has been steadily building up a stable of quality hardware products, first starting with the LA-2A and 1176 legacy compressors and, more recently, units such as the 8110 and 4110 mic preamps released last year. The latest additions to the company’s profile are the slick and portable Solo 610 (tube) and Solo 110 (solid-state FET) mic pre/DI boxes.

The lunchbox design is nothing new: Martech used it with great success on its MSS 10 preamp. What’s nice about this design idea is that it makes it easy to put the preamp out with the player/singer, making for cleaner cable runs at line-level. What’s new is this kind of performance and feature set at such an affordable price.

Both units are housed in rugged black steel boxes with rubber handles on the top (more on that later), XLR I/Os on the back and ¼-inch input and thru plugs on the front, making them user-friendly in the control room, stage or studio. All buttons, pots and toggles are top-notch. Both units carry all the same functions, but are differentiated at first by looks and then by sound. The Solo 610 (9 pounds) has a retro look with old-school aircraft-style knobs with toggles for all major functions: mic/DI, high/low impedance, phantom power, low-cut filter, polarity on the front panel, and mic/line and ground lift on the back. The Solo 110’s (5.4 pounds) knobs look more modern, and the unit uses blue LED buttons for all major functions. Gain and level knobs are the main volume controls on each unit, allowing you to provide a bit of crunch if desired by overdriving the input stage. Both units feature a tri-color LED for input gain and a blue power-on LED.

Go to the Focus on Universal Audio page to see video and learn more about UA products

Where the units differ most is in output gain: The 110 provides a clean 77 dB of gain through the 600-ohm input and 75 dB through the 2k in, while the 610 offers 60 dB through the 500-ohm input and 55 dB through the 2k in. As stated, the 610 is a tube unit, using a single 12AX7 and 6072 for the tube complement.

The first outing for the 610 was as a DI on an Elrick Gold Series 5-string active bass. The unit was in the room with the player and the feed was then run at line-level into the studio. The rugged and portable 610/110 design gives you no qualms about setting it on the floor, table or windowsill in the studio and having either the talent or an assistant tweak the levels to perfection. The unit was set to DI with the impedance switch set to high and the output switch on the back set to line out. I experimented with the impedance switch set at both low and high, but it oddly made no audible difference in level or tone.

For this active bass, it was tricky at first to get the gain structure figured out. I adjusted the gain knob until it lit up the input LED to what I thought was optimal and then ran the output as a master volume to tape, but the bass was breaking up when the player hit it hard, even though I was in the “legal” zone according to the LED. Then I tried the counter-intuitive approach and set the output level control to maximum and adjusted the input to optimal. This configuration turned out to be perfect for this situation. The sound was full, rich and warm with plenty of low end, just what I expected from a tube unit of this price and quality.

Setting up the gain worked in the completely opposite manner on another date with another bass player using a passive bass. The input was set optimally and the output used as a master volume control as you would expect. The nice thing about this unit is that it can adapt to just about any situation. In both cases, it sounded big and round, with plenty of bottom and nicely rounded transients, giving it a mildly compressed sound. The bass sat right down in the track and felt great with the kick drum.

Later that day, I ran the bass into the 610 and then through to the 110 for a side-by-side comparison. After levels were matched, the 610 exhibited more of a pronounced low end, while the 110 was more clinical, with more precise transients and less color and personality. Although both sounded very good, in this application, the 610 was the clear winner.

The next test for the 610 was as a kick drum mic preamp. A Sennheiser e 602 was plugged directly into the box in the studio. The kick drum sounded full and clean with a nice low-end component, perfect for this application. Later, I heard the 610 used as a preamp with a newly refurbished AKG 414 B-ULS used as a mono overhead. The top end was clear, with snappy transients and a nice, even low end. The nice thing about the tube and transformers is that you get that nice crunch when you hit it hard. This was completely variable based on how you set the input in relation to the output and was easy on the ears.

Next, the 110 was put to use on a male vocal. The factory-refurbished AKG 414 B-ULS was run into the box, which was put on the floor in the vocal booth. Going with what I learned on the bass recording, I ran the output level full on and set the input level after that, but that setup proved too hot. For this application, the input level ended up being set about 10 o’clock, while the output was set at 3 o’clock. This unit has plenty of headroom and, sonically, the mic and preamp married perfectly. The 110 was transparent and crystal-clear, and made it sound like the singer was in the control room. The combination sold many in the room on this combination for vocals.

Just a few minor gripes marred my experience with the 610/110. The lighted switches on the 110 are slick, but there was no documentation as to which position referred to which label. This is not a big deal unless you’re a first-time user and you’re using a ribbon mic where phantom power would be critical or the line/mic button on the back when it would result in a blast of volume in the control room, which unfortunately happened. Another oddity is the In vs. Out label attached to the polarity switch. Does that mean the signal is absolutely in or out of polarity, or does it mean the out of polarity switch is “in” or “out”? C’mon, guys!

Also, the handle seems a bit flimsy. It is made of a very pliable rubber and although it’s impossible to see, it doesn’t seem that there’s any reinforcement at the end where it’s fastened to the box.

Other than these small issues, the Solo 610 and 110 shined in every application. What’s really exciting is this kind of quality and sound at this price. At $799, these babies are not only affordable for the studio engineer looking for both another preamp flavor and something that can cleanly drive a ribbon mic, but also for the bass player looking for a great-sounding, solid DI that can handle input from the hottest bass down to the good old passive model, and do it with style.

The Solos get the highest marks in the three “p”s: performance, price and portability — it doesn’t get much better than this.

Universal Audio, 866/UAD-1176,

Kevin Becka is Mix’s technical editor.



Circuit Topology: Discrete Class-A FET
Mic Input Impedance: 500/2k ohms, switchable
DI Input Impedance: 2.2k/47k ohms, switchable
Max Gain, DI Input: 57 dB
Max Gain, Mic Input: 77 dB (600-ohm input)
Frequency Response: 10 to 60k Hz, ±0.2 dB
Power Requirement: 90 to 250 VAC
Dimensions: 5×5.75×14 inches (H×W×L)
Weight: 5.4 pounds


Circuit Topology: One 12AX7, one 6072 tube
Mic Input Impedance: 500/2k ohms, switchable
DI Input Impedance: 2.2k/47k ohms, switchable
Max Gain, DI Input: 37 dB
Max Gain, Mic Input: 60 dB (500-ohm input)
Frequency Response: 20 to 20k Hz, ±1 dB
Power Requirement: 100 to 130 or 200 to 240 VAC
Dimensions: 5×5.75×14 inches (H×W×L)
Weight: 9 pounds