By Mitch Gallagher
Time for a math lesson: A Universal Audio M-610 tube mic preamp has a list price of $1,295. One of the company's LA-2A optical compressors lists for $2,995. Put the two together, and you've got a grand total of $4,290. So how the heck have they managed to put out the LA-610 - basically a combination of the two products - for $1,749 list? Even compared to the $2,495 Universal Audio 6176 channel strip - a combination of the 610 and the 1176 compressor/limiter - the LA-610 is surprisingly inexpensive.

Granted, the optical compressor in the LA-610 isn't quite the same as the venerable LA-2A, but it's very close. The compressor uses the same T4 optical cell as is used in the LA-2A, and provides response similar to the original. Unlike the LA-2A, the LA-610 doesn't have sidechain high-frequency adjust, nor can you link two units for stereo operation. And, unlike the 6176, you can't use the preamp and compressor independently. (You can, of course, bypass the compressor/limiter, or use the line input to feed the compressor, but you can't use the two sections on separate signal paths the way you can with the 6176.)

Are those differences enough to explain the relatively low price? Who knows . . . and really, who cares? What's important is that Universal Audio was able to accomplish the task. (Okay, according to Universal Audio, there are other reasons: the LA-2A is laboriously hand-wired, contains some very expensive components, etc.)

THE TOUR
EQ reviewed the LA-2A and M-610 in the past (April 2001 and June 2001, respectively), so I won't re-hash what's already been written. Instead, let's take a quick tour of the LA-610.

The preamp section has selectable input impedance, 15dB pad, phase invert, and phantom power. Gain is set using two knobs; a 5-position Gain control, and a large Level control.

Two bands of shelving EQ round out the preamp section, High and Low. The EQ has &lusmn;9dB of gain for each band, and each can operate at one of three frequencies. For the high EQ, you can choose among 4.5, 7, and 10kHz. For the low EQ, you have 70, 100, and 200Hz.

The T4 optical compressor/limiter offers extreme ease of use; there are only two knobs required: Peak Reduction and Output Gain. Both are nice and big for easy adjustment. The last two controls on the front panel set the T4 to compression, limiting, or bypass, and determine where the meter falls in the circuit. Speaking of meters, the LA-610 has a cool backlit analog VU meter. There's a recessed meter calibration pot on the front panel. The review unit's meter was slightly out of calibration when it arrived; a quick tweak brought things into alignment.

Around back, things couldn't be more straightforward: There are line and mic XLR inputs and an XLR line output. A front-panel 1/4" jack accepts instrument-level signals. The input selector knob lets you choose among mic input at 500 or 2,000 ohms, line input, or Hi-Z (instrument level) input at 47k or 2.2M ohms. This allows you to have all the inputs connected at the same time; just select the one you want using the knob, and you're ready to go.

THE SOUND
As with the M-610 and 6176, the LA-610 preamp's Gain and Level controls interact. The Gain control is a 5-position switch, offering -10, -5, 0, +5, and +10dB increments. Changing this switch not only changes the input gain, but also affects the tube's harmonic distortion. The Level control is a continuous knob; setting it higher and the Gain control lower results in a cleaner sound, turning Gain up and Level down makes the sound rounder, warmer, and more "tube-y."

The EQ is useful for basic shaping, but isn't designed for "surgical" purposes. The EQ gain is set using 11-position rotary switches; the smallest switch increment is 1.5dB, so don't look for fine control over tonal shading here.

The compressor is similar in response to an LA-2A. The manual describes it as slightly more colored sounding than the original, and I'd have to agree - to my ears it's a tiny bit more aggressive. But it's still a nice, smooth compressor, especially when used for minimal gain reduction. As on the LA-2A, there are two operating "modes": compression, which is gentler with a lower ratio, and limit, which has a higher ratio.

Combined, the preamp, EQ, and compressor offer a tremendous range of sonic shading. You can set the LA-610 for transparent, clean operation, or you can punch things up, adding substantial girth to the input signal.

But even when running clean, the LA-610 adds a roundness to the signal and subtly tames strident highs. I tracked vocals, acoustic and electric guitars, and electric bass into Pro Tools using the LA-610. In every case I was thrilled with the result. On mic-level signals, the LA-610 preamp provides great dynamic response, good presence, and even frequency response.

After tracking, I ran the signals back out through the LA-610. Even with the compressor bypassed, and the EQ set for no boost or cut, there's a subtle character added to line-level signals. The EQ is easy to dial in for broad tonal shaping. The LA-610's high EQ is sweet, without harshness. The low EQ is round and smooth.

Setting the compressor couldn't be easier: Set the Peak Reduction knob for the amount of compression or limiting you want, then adjust the Gain control to make up for level lost due to processing. Easy. The meter can be switched to display the preamp output level, gain reduction, or compressor output - a big help for getting the levels where you want them. A nice addition would be a signal present/overload LED on the preamp input.

TRUE VALUE
Remember our math lesson from the beginning of this review? No matter how you run the numbers, the LA-610 works out to be a pretty good deal. Basically, buy a 610 preamp for $1,299, and Universal Audio throws in an LA-2A-style compressor/limiter for an additional $450. (These are list prices, of course; you'll likely find lower street prices.)

Not bad at all considering the sound quality and versatility this buys you. You get a tonally flexible tube preamp, two bands of shelving EQ with switchable frequencies, and a smooth, high-end compressor/limiter.

Whether you're after transparency or thick, punchy tones, the LA-610 can deliver. Use it as a channel strip, a mic or instrument preamp, for EQ, or as a compressor. No matter how you set it up, you'll get low noise, great-sounding results.

Add it all up, and you get a great value. That's the kind of math I like best.