Solid State Power Amp Reviews

I also ran my reference Musical Fidelity kWP single-ended preamp into a single 9007 configured for stereo, though mbl of America's Jeremy Bryan made clear that the stereo configuration was intended more as a convenience for those who couldn't afford to buy two 9007s at once, and that it wouldn't sound nearly as good that way.

He was right. You don't want to buy a $13,300 Reference 9007 and use it as a single-ended stereo amp unless you plan on adding a second one some time soon. The 9007's performance in stereo mode, while competent, was not particularly distinguished for a $13k amplifier. In fact, it sounded spatially flat, anemic, and somewhat bright. Run as balanced monoblocks, two 9007s took on a considerably different personality.

The 9007 produced an appealing sense of continuous, liquid musical flow, combined with exceptional transparency and taut, rhythmic assertiveness. The amps presented a sonic picture that was coherent and whole—a prerequisite for $26,600/pair. While never bright, hard, or brittle, the overall presentation was nevertheless oriented more toward rhythmic drive, transient speed, and clarity than toward harmonic richness or textural suppleness. These qualities made the 9007 a perfect complement to the Mac C1000's moderate tendency toward delicacy, richness, and midband bloom.

Compared to the presentation of my reference Musical Fidelity kW amplifiers, the mbls sounded faster, somewhat more effervescent, and more "together," notes appearing instantaneously out of a black background and disappearing into the ether with equal speed—perhaps a result of the amplifier's ultra-low noise floor.

The 9007's fast attack and decay were especially well suited to reproducing music with heavy rhythmic drive. I recently acquired a copy of the vinyl edition of Give Up (Sub Pop SP595), by The Postal Service, the synth-heavy side project of Death Cab for Cutie's Benjamin Gibbard. The music—built from the sounds of drum machines, electronic blips, and occasional electric guitar and piano—sounded absolutely pristine, each carefully chosen element hovering and shimmering, tightly focused in three dimensions against the blackness.

When I hear a component excel with surgical precision at a particular musical task, as the 9007 did with percussion, I pick through my record collection looking for more such challenges. After Give Up, I pulled out an original LP (New World 319) and Classic's reissue of Pulse! , and reveled in John Cage's Third Construction, written for four percussionists playing everything from 20 tin cans of various sizes to tom-toms, claves, gongs, ratchets, cowbells, maracas, and even a conch shell. At one point a rubbed bass drum creates an explosion of low-frequency energy. The mbl 9007 delivered this stupendously recorded piece the way it was meant to be heard: with razor-sharp clarity, equally nuanced rich textures, and full-throttle dynamic authority.

I then moved on to an original pressing of Philip Glass's Einstein On the Beach (LPs, Tomato 4-2901), which is a genius, a genius piece, a genius piece to, a genius piece to, to, too, two, three, four, actually, to actually bring, to actually bring to, to actually bring to a crowded, to actually bring to a crowded beach, to a crowded beach, and play and play on a boom, on a boom box. After five minutes of it, the people around you will run screaming and you'll have a clear patch of sand to yourself. Anyway, I like Einstein; a while back, I sat through all four hours of it at the Brooklyn Academy of Music. This time, I sat through only one side. The 9007s reproduced the synthesizer parts and the male and female voices with bell-like clarity, offering sharply focused three-dimensional images, taut transients, and total freedom from smear, while decisively carving out and plumbing the depths of the low-bass synth notes.

Though the 9007 was a somewhat cool customer, less "ripe" than some other amplifiers I've encountered, it managed to effectively capture the harmonic structures of instruments on familiar recordings, reproducing with great clarity the texture and tonality of pianos, for instance. I pulled out Nat "King" Cole's 1956 trio recording After Midnight (LP, Capitol W782) one evening, and this mono recording's three-dimensionality and instrumental palpability were impressively revealed thanks to the 9007's musical grip. Rhythmically, the record had never sounded more assured, though it had less of its familiar tubey warmth and "golden glow" than I'm used to.

Andrew Litton and the Dallas Symphony Orchestra's recording of Mahler's Symphony 2 (CD, Delos DE 3237), which I picked up during a recent visit to Dallas, demonstrated the 9007s' impressive dynamic reserves and soundstaging prowess, as well as their harmonic capabilities. While the amps' midband was somewhat reticent compared to my reference kWs, and certainly when compared to what tube lovers might expect, I found that the cellos and basses on the right side of the orchestra sounded woody and full-bodied, and the brass had a proper velvet glow and sufficient bite to satisfy, though the 9007s were more "event-oriented" than emphasizing tonality and texture. When timpani mallets hit drumheads, the emphasis was more on the impact than on the ensuing reverberation.

Well-recorded female voices confirmed that while the 9007 was not the richest-sounding amplifier you'll ever hear, neither was it thin or bleached-out. Its tonal balance tilted only slightly to one side: it could tidy up and clarify a too-warm recording or ever so slightly lean out a neutral one. More important, its balance was consistent throughout the audioband, giving it the coherence and authority one expects at this price point.

The 9007s' imaging and soundstaging were up there with the best I've heard: tightly focused, not edgy, and presented with great solidity and three-dimensionality. The 9007s produced believable, palpable, properly sized images on stages whose width and depth were appropriate to the recording. The "black" backgrounds added drama to the picture.

Overall, what made the Reference 9007 an exciting, credible performer was that it spoke with a singular voice: It was as fast on top as it was on the bottom. It delivered sparkling, transparent, shimmering highs, and tight, well-damped bass. The 9007 never sounded mechanical or thin, nor did it show any grainy, bright, or etched seams. While it sacrificed a bit of bloom and suppleness to deliver the music with crystalline transparency, the tradeoff was more than worth it. The Reference 9007 was among the most exciting and engaging amplifiers I've heard.

Conclusion
I have come to appreciate what lots of power can bring to an audio system. An amp working at the lower end of its power limits always sounds more relaxed than one asked to perform at or near its upper limit (lovers of mini-watt single-ended-triode amps, start screaming now). Even though the mbl Reference 9007 used as a monoblock is rated at a prodigious 440W into 8 ohms and delivered authoritative, powerful musical experiences, it couldn't scale the dynamic peaks produced by my 1000W references, the Musical Fidelity kWs, or provide the kWs' weight and sense of ease. But in other, very significant ways I felt the 9007 outperformed the kW: in terms of rhythm'n'pace, overall coherence, and high-frequency transparency, where it set new standards in my listening experience.

Overall, the mbl 9007 struck me as delivering almost as much detail and resolve as the big Halcro dm68s, which I was fortunate to spend some time with—but with greater musical flesh on the bone and more intense emotional involvement. The 9007 offered sound about halfway between the sweetness of the far more powerful (and less than half as expensive) Musical Fidelity kW750 dual-mono amp and the resolution, ultralow distortion, and analytical prowess of the big Halcros. That's saying a lot.

While a single Reference 9007 can be configured as a single-ended stereo amplifier, I don't recommend this except as a temporary measure for buyers who can't afford to buy two at the same time. But as a pair of monoblocks, the mbl Reference 9007's exceptional qualities of sound, build, and appearance justify its high price. Here's hoping its measured performance backs me up. If you're comfortable spending $26,600 for a pair of solid-state monoblocks, add these to your list.