Integrated Amp Reviews

For decades, I read all the British and American audio magazines, and I pretty much believed everything written therein—with one exception. The equipment reviews published in Stereo Review had an off-puttingly disingenuous quality. I learned a lot from the magazine's reviews of recordings and loudspeakers, but every time senior editor Julian Hirsch wrote that any amp with sufficiently high power, low measured distortion, and high damping factor would sound the same as any other with similar qualifications, I felt estranged from my favorite hobby. Stereo Review's arrogance came off as duplicitous and self-serving. The magazine seemed committed to stamping out all forms of individualized audio connoisseurship.

While Stereo Review was making such claims, I owned Dynaco A50 loudspeakers and several appropriately powered tubed and solid-state amplifiers. Every time I swapped amps, the sound of my E. Power Biggs and Jascha Heifetz records changed in unsubtle and unmistakable ways. When I noticed this, I would shout, "Julian! Can't you hear this? Stop listening with your oscillograph!"

Eventually, I realized that each of us could hear only what we know to listen for.

Thereafter, every time I met a loudspeaker designer, I was compelled to ask: "What amplifiers did you use to voice your speakers? What power amps do you recommend to your customers?"

Mostly, I'd get dodgy, Julian Hirsch–type answers: "Well, my speaker will work with any amp of sufficiently high power and current capability."

Lately, I've met a few designers who at first say exactly that—but who then, when pressed, look me in the eye, lean close, and whisper, "But we mainly used a Hegel! [wink-wink]" I've also been noticing, at audio shows, a lot of excellent-sounding rooms sporting Hegel amps. Clearly, more than a few speaker designers and show exhibitors think these Norwegian-made amps sound different enough to give them an advantage over their competitors.

Curious
I went online and read every Hegel review I could find. Each seemed to describe what I'd heard in those Hegel-equipped rooms at audio shows: Hegel amplifiers make music sound more visceral and well proportioned than other amps in their price range. In my experience, every amp-speaker combination imposes a unique character on the music. Every combination feels, to some degree, harder or softer, or denser or leaner, or darker or lighter, or stronger or weaker than some other combo. But recently, whenever I heard speakers powered by a Hegel, I noticed something else—something almost indescribable that I'd never experienced before. The Hegels appeared to have a way of "fixing" something—something I hadn't even realized had been wrong with most other amps I've enjoyed. I became so intrigued by my evolving Hegel experiences that I contacted Eileen Gosvig, the charming and knowledgeable national sales manager for Hegel Music Systems USA, to obtain a review sample of the new H160 integrated amplifier ($3500).

A few weeks later, Gosvig brought to my steampunk Bed-Stuy man cave a Hegel H160, the also-knowledgeable Anders Ertzeid (global sales manager), and the suave Harry Bromer (Bach Sales Group). I kept them all busy with nervous Herbchat, organic grapes, and Jarlsberg cheese as I hooked up their very solid-feeling integrated.

Description
While trying to be a good host and connect wires at the same time, I discovered the Hegel H160's unusual selection of inputs. "We designed an integrated with a broader set of connections than any other amplifier on the market," Hegel states on their website.

This had me scratching my head, because the first thing I wanted to do was connect two turntables. But the H160 does not include a phono stage or an option for one, and its "broader set of connections" includes only one analog (RCA) input and one balanced (XLR) analog input. I have at least 10 phono stages and three turntables, but none has symmetrical circuits or XLR outputs. The only other analog (RCA) input is for home theater, which bypasses the volume control. And when I saw that the H160 had six digital inputs—one coaxial/RCA, three optical TosLink/EIAJ, one USB, and one LAN-RJ45 (for streaming music from devices with DLNA; wireless streaming is also available via Apple AirPlay)—I felt obsolete and disconnected. And where's my Mono switch? And my Balance control? I pouted despondently and stamped my little foot.

My self-esteem improved when I scrutinized the H160's front panel, which is handsome and understated in a timelessly masculine way. It has only a rotary selector switch, a blue-lit display, and a rotary volume control with a sexy, silk-suit feel.

Today, many solid-state amplifiers are variations on class-D output topologies; the Hegel H160 is more old school. Instead of using the now-ubiquitous Hypex output module, Bent Holter—Hegel's founder, CEO, and chief designer—opted for discrete bipolar transistors operated in class-A/B. Plus, Holter added a "new" twist in Hegel's DualAmp Technology. He separates the H160's voltage-gain duties from its current-delivery tasks by generating the amp's 32dB of voltage gain entirely in the first stage. Current delivery is then accomplished separately, in the Hegel's unity-gain output stage. Enhancing that topology, the H160 uses separate, specialized power supplies for each stage. Hegel calls this strategy its DualPower Technology. (Dette er nytt?)

I have always believed that the main problem with traditional amplifier measurements was simple: Music is neither a sinewave nor a squarewave. The whack of a snare drum or the pluck of a bass string generates complex, wildly irregular waveforms with insanely intricate shifts in power and voltage levels. Bent Holter agrees, and thinks he has addressed this issue of "waveform asymmetry" in his Hegel amplifiers.

Simply stated, all tubed or solid-state (push-pull) output stages are statically balanced using sinewave inputs until they are pushing and pulling in relatively equal ways. But according to Holter, "the main problem of using push-pull output stages in high-power audio amplifiers is that the music signal is dynamic and asymmetrical most of the time. These kinds of dynamic signals make the temperature of the transistor silicon go up and down with the signal. Unfortunately, the current/voltage transfer curve of the power transistor changes when the temperature changes. Because of this, there will be a kind of memory effect where the instantaneous and recent dynamic historical signal will decide what is the actual temperature point of the transistor silicon. Because the temperature will change the transfer curve of the transistor, the transistor will always move away from any static matched transfer curve. . . . Hegel amplifiers use a unique and patented technology called SoundEngine. This new amplifier topology solves the problems of dynamic crossover distortion."

As I typed all that, my mind kept singing, "and it don't mean a thing if it ain't got that swing!"

Listening
Alone, sequestered in my chambre secrète, I began my Hegel reviewing experience with flutist Gastone Tassinari and I Musici di Roma's recording of Vivaldi's beguiling Four Concertos for Flute, Strings, and Continuo in d, Op.10 (LP, Philips 835005). This mesmerizing recording never fails to transport me to the exotic corners of my imagination. Even with the not-yet-broken-in H160, spatial cues, atmosphere, and instrumental tone were such that all I could do was smile and dream.