Viola Audio Laboratories Cadenza preamplifier
By Wes Phillips   •   December, 2005 "So what are you reviewing now?" A polite question, considering that my old friend Randy is definitely not an audiophile.

"A really interesting preamplifier from Viola Audio Laboratories. It costs $16,000." I wasn't sure Randy knew what a preamplifier was, but I thought the price might get his attention.

"Wow—that better be the best in the world!"

You'd think so, wouldn't you? Especially a preamp that doesn't even have a remote control, which Randy's department-store rack system has. However, the thing that made this too deep a subject for a cocktail-party conversation was that, good as the Cadenza was, it was making me question the whole concept of "best." Is a Stradivari violin better than a Guarneri? Is either really better than that fiddle your uncle Arthur made in his workshop?

The answer probably depends on whether you're asking your intellect, your ears, or your heart.

A brilliant solo passage
Viola Audio Laboratories may be a new company with an unfamiliar name, but it has deep audiophile roots. It's the latest incarnation of part of the brain trust behind Cello Music and Film: audio designers Tom Colangelo and Paul Jayson, both veterans of the original Mark Levinson Audio Systems (MLAS); and COO Tony Disalvo (who has since left Viola to pursue other interests).

Viola is bucking the whole trend toward "convergence." It makes exclusively two-channel gear and steers clear of digital design, its designers having already proven to themselves that even something as "basic" as analog design requires a lifetime of mastery. In their words, Viola creates "top quality audio reproduction in the tradition of the early MLAS equipment: best parts, highest standards, close inspection, quality workmanship, and simple design." And, oh yeah, "a belief in the validity of measurement as well as an acceptance that music is experienced in addition to being measured and delivered by mathematical formulas."

The Viola designers work as a team, but, as in a Beatles song, one member generally takes the lead while the other one makes it better. In the case of the Cadenza, Paul Jayson was the primary. The Symphony power amp, which I also used to audition the Cadenza, was more Tom Colangelo's baby.

The Cadenza uses an external choke-input power supply, a topology that Jayson says produces less electromagnetic interference than a conventional capacitor-input design. It also produces fewer high-peak ripple currents, he says, which means less intermodulation distortion on the power-supply rails and ground returns. Translation: a quieter preamp with a lot less high-frequency noise. Jayson points out that the choke also "cushions" power-supply components from major fluctuations, which prolongs reliability.

The audio portion of the Cadenza employs fully balanced class-A circuits. The motherboard houses the signal switching relays, local power-supply sections, and input and output connectors—a topology that keeps signal paths as short as possible. The amplification stages are handled by three custom-designed OTA gain modules, which combine dual-monolithic FET input and cascode topology to preserve wide dynamic range while minimizing the effects of power-supply variations. Jayson reckons the OTA modules "approximate an idealized gain stage." Constructed from discrete components, each module employs ultra-high-precision (0.1%), thin-film resistors (for their low noise characteristics) and is optimized for its specific application within the circuit.

Jayson designed the input section to have a 1 megohm input impedance, reasoning that high impedances: 1) reduce errors at the connector contact junctions; 2) conserve the source's output drive current, which makes more of the source unit's output current available to drive the interconnects, therefore improving the high-frequency performance and transient response; and 3) preserve the balanced input's ability to reject interference if the output impedances of the signal source are not perfectly matched.

Regarding this last point, Jayson says that small differences—say, 1%—in the output impedances of the two halves of a balanced output (a not infrequent occurrence) can lead to a "significant reduction in the preamp's common-mode rejection ratio (CMRR)—and a consequent rise in the noise level—when used with an input impedance in the conventional range of 10k ohms to 50k ohms. Not so much with high impedances," he says.

The Cadenza's output-stage modules employ a "special kind of compensation which preserves the phase integrity of the balanced output signal across the audio spectrum." Translation: increased timbral accuracy and three-dimensional imaging and soundstaging. The output stage is muted during power on and off.

In addition to its stereo volume control, the Cadenza has two 11-position stepped gain switches that control channel balance and allow input sources with widely divergent output levels to be matched. Jayson placed these in the inverse feedback loop because that's where they're quietest.

Then there's the volume control itself, a custom-made, stepped attenuator with 59 increments of 1dB each. It uses 0.1% Vishay film resistors, and the contact material is a high-gold-content alloy that also contains platinum, silver, and copper. The wiper contact was designed so that "external vibration does not modulate the pressure," because that would affect the sound. This is one sexy volume control—I had to restrain myself from clicking it up and down while cackling Bwah-ha-ha-hah! You laugh, but only because you haven't experienced anything like the tactile sensation of this jobbie.

The Cadenza has four RCA inputs, one XLR, and—a blast from the past—one Fischer bayonet-style input. Outputs consist of one RCA (plus an RCA tape output), two XLR, and one Fischer. (You younguns won't remember Fischer, but early MLAS and Cello components all sported them; it's a legacy thang.) Oh yeah, and there's a space on the circuit board for an option card—a phono section to be announced later...?

And, despite Viola's two-channel emphasis, the Cadenza does have a board-mounted switch that allows you to use either a balanced or a single-ended input as a processor loop if you want to incorporate it into a multichannel system.

The Cadenza has a beautiful chassis, a milled-from-solid faceplate, a great anodization job, and some nice little touches—such as the drilled-out knobs. A great piece of metalwork all around, it's understated, as audio jewelry goes—most of the Cadenza's fancy is on the inside. Its exterior errs more on the utilitarian end of the scale, if anything, which I respect. It's more Bentley than Lamborghini.

An embellishment or flourish
Setting up the Cadenza was a snap. The nice, long umbilical that connects the power supply to the main chassis let me put that hefty PS down on the floor next to my equipment rack. A good thing—at 20 lbs, it weighs as much as many power amps.

The Cadenza's balanced input let me connect the Ayre Acoustics C-5xe universal player in its best-sounding mode, and the preamp's single-ended and balanced output options allowed me to use it with a variety of different power amps. (I had no Fischer-equipped MLAS or Cello gear on hand, so I couldn't pursue that option.)

The Cadenza and its PS run cool, so ventilation wasn't a big issue, though the generous vents in its top plate gave me a start one evening when I noticed they were glowing bright crimson. I walked over to the preamp and bent down to peer inside. It sure was red in there. I asked Jayson about it. "Those are LEDs. They just mean the power supply is operating correctly."

Do they change color if it isn't?

"No, they don't turn on if there's a problem—and neither does the preamp."

Viola also supplied their 200Wpc Symphony power amplifier for the audition, because everyone there thought that was the way to hear the Cadenza. I also listened to the Coda S5, Conrad-Johnson Premier 350, Ayre V-5xe, and NuForce Reference 8 monoblocks.

A final usage note: It may seem obvious, but the absence of remote control means there's no remote control. Duh. Deal with it—or look for another preamp. At first I suffered from Phantom Remote Syndrome, but I soon adjusted. Actually, I began adjusting loudness before I cued the music and rediscovered my old talent for getting that right—mostly. The Cadenza is a preamp for purists, but I liked it, too.

The fall or modulation of the voice
In a properly run universe, obviously, a preamplifier can't make a whit of sonic difference. I'd like to report that I couldn't hear a thing that the Cadenza did. I mean that literally: I'd like to report that. But it just weren't so.

Cuing up the ReBirth Jazz Band's "You Move Ya Lose," from Do Whatcha Wanna (CD, Mardi Gras 1003), I was slammed into my listening chair by the sledgehammer strut of Philip Frazier's tuba line, followed by the snare drum's ratatatatatatttttttt. (Bet you didn't know you could put a burr on a tat. Actually, I can't, but ReBirth's Derrik Tabb sure can.)

But it wasn't just the muscular attacks, bass solidity, and vivid textures that impressed me. The Cadenza delivered ReBirth's restless energy and sinuously shifting lines better than I'd grown used to hearing them. ReBirth is a jam band, and when it plays, it tends to bulldoze over the conventional structures that normally define the songs it pounds out—the guys seem to cram extra measures into these tunes' conventional 32-bar structures. This is vividly apparent when you hear 'em live—and this sort of fluid shifting in and out and around the form was more evident through the Cadenza than I could remember hearing before from Do Whatcha Wanna. Hmmm, I thought. This has got to go in the demo pile.

Whoa! Sometimes it just makes you want to shout Bamalama.

As I paired the Cadenza with the different power amps and speakers marching through the house (primarily the Peak Consult Empress and the Thiel CS2.4, with and without Thiel's SS1 subwoofer, I continued to be impressed with the physicality and agility of the sound, and with textures that leapt out as new from recordings I'd been listening to for ages. The Cadenza was one of those audio products that had me rooting through my collection for the good old stuff—and rewarded me with millions of little epiphanies.