Hovland Radia power amplifier

For better or for worse, appearances can make a profound first impression. Think of the bold, muscular curves of an Audi TT coupe, the planes and facets of a Lamborghini Murcielago, the sleek lines of a Gulfstream jet. In these vehicles, function and art are combined with smooth facility and perfect aesthetic balance.

The Hovland Radia power amplifier, introduced at the 2003 Consumer Electronics Show, makes exactly the kind of vivid visual impression as a fine sports car or an Ermenegildo Zegna suit—to see it is to want it, even if all you know about it is how it looks. To describe the Radia as "gorgeous" is an understatement; its looks alone make it as worthy of a spread in Architectural Digest as in Stereophile.

But this is Stereophile, so the Hovland's stunningly pretty face won't by itself be enough to get it by, though when combined with its price—$10,000—beauty like this does raise expectations. Does this bombshell have the depth and moxie to back up its looks, or is it the audio equivalent of Britney Spears: a traffic-stopping but hopelessly dumb blonde, all sizzle and no steak?

They will make no amplifier before its time
To learn the basics of the Radia's design goes a long way toward answering that rhetorical question. The Radia is the Hovland Company's first solid-state product, and, like all of their products, it was a long time a-brewin'. Bob Hovland believes firmly in taking as much time as is necessary to get it right. In the case of the Radia, that meant a total of 25 years of experimentation with circuit topologies and parts, extensive development work, refinement and re-evaluation of basic concepts, and careful consideration of the suitability of every component, active and passive. Whew!

In the white paper on design and tech info that Hovland's Alex Crespi sent me, much is made of the fact that the Hovland design team considers each component to be a system—and that each individual component is a subsystem of the entire hi-fi reproduction chain. Hovland's approach is holistic in nature, and specifically disclaims any one technical feature as being more important than any other—everything "from resistors, to active devices, to fastening screws" is taken as a vital part of the design as a whole.

The Hovland Co. also takes pains to point out that no component can be better than the signal supplied to it, and that "under optimum conditions the best performance that can be achieved is to provide an amplified version of the signal that is equal in quality to the signal it receives." (Footnote 1) Hovland also explicitly acknowledges that there is no such thing as a "no-compromise" component, and that the designer's job is to "develop a comprehensive and real world understanding of what is meaningful in design and where to make informed compromises." An eminently sensible approach, methinks.

Despite disavowal of any "magic bullet" topologies, parts, or construction techniques, Hovland does provide a lengthy list of things that they think contribute substantially to the Radia's performance. The amplifier is fully dual-mono internally, its two channels sharing only the power cord. The power supply was the subject of much effort, and uses "oversized power transformers" for each channel, in tandem with ultra-high-speed capacitors and Schottky rectifiers. The input stage employs matched J-FETs for high input impedance and optimum DC offset stability, and the fully symmetrical circuit topology uses four bipolar, metal-enclosed TO-3 output transistors per channel. All internal wiring is Hovland's own Generation 3 shielded, silver-plated interconnect, Hovland Reference speaker wire, or military-spec, Teflon-insulated silver-plated wire, and extensive use is made of Hovland's own MusiCap film-and-foil capacitors in key circuit locations. Thorough protection circuits shield the Radia from unexpected electrical events. The Radia is available with either RCA or balanced XLR inputs, and has a remote turn-on jack on its rear panel.

Then there's the industrial design. As you may have gathered, the Radia is one of the loveliest-looking pieces of audio gear I have seen. Simplicity, functionality, and elegance have been Hovland's watchwords, evidently, and the diffuse effect of the front panel's seven sapphire-blue lights in a dark listening room is quite sexy. The lights can be turned off, should you care to listen in total darkness.

The Radia's chassis is also worthy of description, as it's not an example of art for art's sake. Designed as an active part of the amplifier's performance, it is a multilayered monocoque that provides exceptional rigidity of support for the internal components, as well as extensive damping to isolate the Radia's innards from the outside world's intrusions. The bottom of the chassis consists of three layers: two different thicknesses of a "high-strength alloy plate" coupled to a ¾"-thick plate of machined acrylic.

Inside, the power transformers are isolated from the chassis by three different damping mechanisms. Two different visco-elastic polymers are used in combination with a solid plate installed with damping compound. The entire case is designed to maximize heat dissipation through heatsinking and convection cooling, and it worked beautifully: No matter how hard and long I drove it, the Radia was never more than slightly warm to the touch anywhere. The customer can realistically expect great pains to have been taken with an amplifier costing this much, but the careful attention Hovland has lavished on the smallest details is truly impressive.

Setup was minimal. Given the large number of other amps I had on hand, I placed the Radia atop three Silent Points isolation footers (points down) on the thin carpet covering the concrete floor of my listening room: the hefty Hovland was effectively coupled to the slab.

Round 1
To create a top-flight piece of audio gear, careful design and beautiful cosmetics are necessary but, in themselves, insufficient. In the end, it is sonic performance that gives not just pride of ownership but long-lasting satisfaction. And here things got a little complicated.

At the beginning of my audition, the Hovland Radia's most outstanding qualities were its just-right focus and a floaty, easy, tubelike roundness. Early on, with the Stereovox speaker cables between the Radia and the Legacy Focus 20/20 speakers, the amp had speed and detail—but bass, while cleanly and clearly defined, was too lacking in weight to be fully convincing. The lowest bass was soft, and the transition from the upper bass to the lower midrange was even more so. "Refined, smooth, and classy, with impeccable manners," read my listening notes, but there was a definite lack of authority in the Radia's presentation. There was also a dash of haziness and insubstantiality in the upper treble—a somewhat gauzy, misty character.

With Earl Wild's spectacular traversal of Rachmaninoff's Rhapsody on a Theme by Paganini (LP, The Romantic Rachmaninoff, Reader's Digest/RCA RDA-29A), the Radia had eye-opening clarity and transparency through the vital midrange, but seriously lacked oomph. When I listened to Josef Krips and the Amsterdam Concertgebouw's performance of Mozart's Symphony 40 (LP, Italian Philips 6998 010), the Radia showed itself to be exceedingly insightful as to inner details of the music, if a bit better at micro- than macrodynamics. The Hovland shone from pp to mf, but sounded a bit reticent when handling wider-scale dynamics.

I experimented with cables, substituting the Cardas Golden Reference biwire speaker cables between the Radia and the Legacys. The somewhat diffuse focus resulting from the too-soft treble improved but did not disappear. I listened to the Radia with four different sets of speaker cables on the Legacys, and each had a strikingly different presentation. The speed of the Nordost Valhalla and Stereovox LSP-600 made for a substantially different presentation from the slightly rounder, mellower Cardas Golden References. A brief encounter with Synergistic Research's new X-Series cables was also most enlightening (footnote 2).

Overall, I listened to the Radia for six weeks or so, becoming accustomed to what it did well but always remaining aware of its shortcomings. I wrote up my findings and shipped the amplifier to John Atkinson for him to do his usual technical analysis. As you can see from the "Measurements" Sidebar, this first sample of the Radia suffered from an internal grounding problem. When Hovland received the preprint of the review, they claimed that the review sample no longer represented current production. They asserted that they had made a significant change to the Radia's grounding circuitry since the review sample was manufactured, and that the grounding change would result in significantly superior performance, both sonically and on the test bench. So a second Radia was dispatched to me for auditioning, and JA returned the first one to me so that I could compare the two Radias directly.

Footnote 1: While seemingly obvious, the latter is a point often overlooked, particularly if a listener is married to a particular set of sonic characteristics.—Paul Bolin

Footnote 2: I'll report on this truly original set of cables in a future issue. Just when you think there's nothing left that can surprise you, something like the X-Series comes along. I have never had to turn on a set of cables before.—Paul Bolin

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