Hyperion HT-88 monoblock power amplifier Page 2

In recent weeks, the Hyperion HT-88s have performed without flaw in two different systems. They've driven those same Quad ESLs, now in my much larger living room (ca 21' by 27'), as well as the Audio Note AN-E/SPe HE loudspeakers in the listening room described above. In both cases the amps were driven by my Shindo Masseto preamplifier (output impedance: 600 ohms), using either Shindo silver or Audio Note AN-Vx interconnects. For the most part I relied on the AC cords supplied with the HT-88s as standard equipment, although some aftermarket upgrades I tried had an audible effect. Speaker cables varied, an old pair of Audio Note AN-SPe silvers giving the best results.

A bit of miscellany: While there were, of course, audible differences among the Hyperion amplifiers' 4, 8, and 16 ohm speaker taps, I always found myself preferring the 8 ohm secondaries. Go figure.

Back to the Quad ESL, a loudspeaker notoriously difficult for any amplifier to drive: Its impedance varies from a peak of 36 ohms (80–100Hz) to less than 2 ohms (at 20kHz), and the trip from one extreme to the other is less than straight. The Quad also demands more voltage than some in order to give full-range sound at reasonable volumes—but its voltage ceiling isn't a great deal higher than its voltage floor, especially if modern protection circuitry hasn't been retrofitted. Consequently, although the ESL is linked in most audiophiles' minds with tube amplifiers, not just any tube amp will do. Of vintage designs, the Quad II and the Leak Stereo 20 top most people's lists, along with a handful of others in the 15–40W range. But be forewarned: A certain amount of global negative feedback, to minimize output impedance and flatten the amp-plus-speaker response curve, appears to be a requirement—one of virtually deal-breaking proportions.


yperion's literature doesn't specify the amount of feedback they've engineered into their amp; the HT-88 exhibited sufficient gain in my system that I assumed its feedback is no more than moderate. In any event, the HT-88 drove the ESL with acceptably flat power response, exaggerated mid- and upper-bass content being objectionable only on certain recordings: 1970s rock such as the Band's Stage Fright (CD, Capitol 25395-2) and Procol Harum's Something Magic (LP, Chrysalis CHR 1130) were among the most trying.

Predictably, small-scale classical music fared best with this combination. And if only because that material is itself why some Quad enthusiasts find the strength to go on living from day to day, the beauty of the pairing can't be ignored.

It was just such a record—the indispensable recording of Brahms' Clarinet Quintet made by members of the Vienna Octet (LP, Decca/Speakers Corner SXL-2297)—that I was enjoying during my first, abortive audition of the Hyperion HT-88. The combined textures of reed and strings was almost indescribably beautiful, and the sheer solidity and presence of the musicians between and behind the Quad panels were memorable. More important, the pacing, momentum, and flow were superb—as good as those qualities get in domestic playback. I was thoroughly involved, thoroughly enchanted by the music .†.†. until, you know, the thing with the hum.

Some pop recordings were well served by the Hyperion-Quad combination. On Jeff Buckley's "Lilac Wine," from Grace (CD, Columbia CK 57528), I was impressed by the levels of nuance and sheer expressiveness in his singing. Sibilants were somewhat pronounced, but that's in the recording itself, and while the Hyperion amp didn't shy away from presenting that characteristic, it didn't exaggerate it, either. The very subtle drum roll toward the end of the first chorus was spine-tinglingly tactile and there, and the sound of Buckley's electric guitar—apparently strummed with bare fingers rather than a plectrum—was colorful and, again, eminently tactile. And on World Party's "Is It Like Today," from Bang (CD, Ensign/Chrysalis 321991 2), the Hyperion-Quad machine latched on to the beat the very instant the bass and drums kicked in, after the ragged opening measures. The downside: The Hyperion's abundance of texture worked against it, calling undo attention to the grain in the "pores" of this mediocre digital recording.

Before leaving the Quads, and notwithstanding my concerns about potentially overcooked bass content, I tried a few discs of large-scale classical music. It's difficult to imagine a more expressively played Bruckner Symphony 5 than the one recorded in 1970 by Lovro von Matacic and the Czech Philharmonic Orchestra (CD, JVC JM-XR24203): Just a few measures into his uncannily slow intro, Matacic combines ritardandi with a succession of startling dynamic accents before leading into an especially colorful, vibrant orchestral tutti and a near-breakneck dance theme. I won't begin to suggest that those and other musical nuances couldn't survive lesser gear, but I came away believing that the Hyperion-Quad combination served them better than most, heightening those pleasures in their timing and intensity. If Bruckner's Symphony 5 were sex with a beautiful woman (which it clearly is not), the Hyperion amp would have been the ice cube on her nipple.

Heard in my smaller room through the Audio Note AN-E speakers, the Hyperion HT-88s surprised me by retaining some of the bass-rich character I heard with the Quad ESLs. But the amp showed that it had enough midrange and treble glow to counter its own occasional heaviness and to prove musically and sonically satisfying in the long term. János Starker and Gyˆrgy Sebök's fine recording of the two Brahms Sonatas for Cello and Piano (LP, Mercury Living Presence/Speakers Corner SR 90392) provided a good example of the Hyperion's overall timbral perspective: Compared with the arguably sunnier Shindo Corton-Charlemagne monophonic amplifier, the Hyperion focused my attention on the weight of the cello and the purr of the piano's lowest strings. Instrumental textures were convincing, if not as real-sounding as with the Shindo, but, more important—and, again, rather surprisingly—it was nice to hear an unambiguously rich-sounding amplifier that was also musically quick enough to get out of its own way: There was no cluttering of attack components, the likes of which can make some electronics seem to distort the flow of the music.

Scores of pop records in my collection benefited from the Hyperions' combination of deep, bass-rich sound and musical speed, and none more than the Grateful Dead's American Beauty (LP, Warner Bros./Mobile Fidelity Sound Lab MFSL 1-014). Phil Lesh's inventive bass lines (guest bassist Dave Torbert's, too, on Lesh's own "Box of Rain") were fat and colorful, yet moved quite well. The same could be said of Bill Kreutzmann's insistent kick-drum playing, which seemed to come up in the mix—bordering, in fact, on being just a bit too much through the Hyperions. The spatial presence of some recorded sounds on this album—the backing voices on "Box of Rain," the guitar that opens "Candyman," virtually everything on "Operator"—was first-rate.

Orchestral music of a decidedly more sensual nature than the Bruckner was also well served, thanks especially to the Hyperion's capacity for expressing the depth and breadth of timbral colors. Nothing showed that off better than Dance of the Seven Veils, from Richard Strauss's Salome, which I listened to in recordings by Herbert von Karajan and the Vienna Philharmonic (LP, London CS 6211) and Artur Rodzinski and the Philharmonia Orchestra (LP, Angel S-60030). The Hyperion did a fine job (you can indeed add "for a tube amp") of controlling the deep bass drum sounds in the former; but the latter, which appears to have been mastered at an unusually high level, gave the amp even more of a run for its money, with ruthe-like tambourine sounds leaping well proud of the mix, and, in the final climaxes, really excellent separation between rich, swooping strings on the one hand and percussion instruments on the other. I was captivated all the way through the final appearance, at the end of the piece, of the oboe, which apparently signals the banality of Salome's evil. Without meaning to paint this product with too limiting a brush: The Hyperion was a brilliant Strauss amp!

What does my Shindo Corton-Charlemagne ($10,000/pair) offer that the Hyperion did not? Turning to Strauss's Death and Transfiguration, on the same Rodzinski LP: from the Shindo I heard more texture and purr from the contrabassoon and the deepest strings, more drama in the staccato notes from all the voices, and an appreciably larger scale overall—all good, lovely things. But the Hyperion was not embarrassed in any of the key criteria for getting to the heart of the music: The cheaper amp conveyed superb tension in the opening bars, and equally superb flow and momentum throughout the piece.

To put it somewhat differently: Through the very expensive Shindo amp, the Bonzo Dog Band's 1969 recording of King Oliver's "Doctor Jazz," from Tadpoles (LP, Liberty), has everything I could ask for: vibrant, present-sounding percussion instruments (spoons, in this case), colorful reeds and brass, and a fine sense of momentum. Through the Hyperion, the record lacked some of those qualities to a small degree—but it was still funny and not just weird.

A comparison of the Hyperion with the similar-sounding Quad II was similarly interesting: The new Chinese amp had literally all of the color and texture of its English forebear—yet with the added benefit of much better bass impact, not to mention wildly better rhythm and timing throughout its range. The Hyperion could rock, whereas the charming old Quad II, God bless it...well, it can sound charming.

With record after record, the Hyperion HT-88 did what I wanted: It found humanness in the recordings I played through it—enough so that the sound sounded like music.

The Hyperion HT-88 probably doesn't have enough negative feedback—unscientific though that observation may seem—to qualify as a great "Quad amp," but it isn't too far off. Especially if you keep your ESLs well away from room boundaries, and especially if your musical diet is limited to jazz, folk, and small-scale classical, you should jump on a pair of these like a hen on a June bug.

Beyond that, it's difficult to imagine a full-range dynamic loudspeaker of reasonable impedance and higher-than-average sensitivity that wouldn't shine with the Hyperion HT-88. If you really understand and prize the value of good timing in domestic audio electronics; if good texture and color are among the things that stiffen your nipples; and if your tastes or your system are such that a mildly bass-rich amplifier will be welcome in your home, then the Hyperion HT-88 would be a fine choice at even $5000 or $6000/pair. At $2800/pair, it's a steal.

Hyperion Sound Design, Inc.
1305 John Reed Court
City of Industry, CA 91745
(626) 968-1022