Solid State Power Amp Reviews

Resisting the strong temptation to hitch ol' Betsy to the sleigh and wassail Stereophile's neighbors, I switched to something a bit more summery—the terrific new orchestral soundtrack from Jurassic Park (MCA MCAD-10859). It begins with three powerful drum strokes (use caution with this if your loudspeakers lack power-handling capability in the deep bass). The drum strokes were powerful and solid through the Brystons, definitely on the full side of neutral but not unnaturally so. The drums were also placed at a convincing depth. Later in the recording the full orchestra enters, and there was a natural lushness to the strings (especially on the lower strings as they echoed the first strains of the compelling main theme). The brass and high strings tend to dryness and thinness on this recording (made in the old MGM, now Sony, Scoring Stage in Culver City, California, site of the late-'70s Sheffield/Leinsdorf direct-disc recordings with the LA Philharmonic). But, overall, the reproduction engaged me enough that I had to fight the urge to run out and see the film again.

But both of these recordings are a shade lean in the midbass area—in fact, both could be considered a bit dry in this region. Over the Brystons/Wilsons they sounded about right—neither too full nor too lean. Further listening to a wide variety of recordings led me to confirm my earlier observation, gleaned during those Mirage M-1si sessions, that the Bryston 7Bs do tend to a rather full, warm low end, lacking that last word in hair-trigger bass-transient response. No problem on the quantity, but the quality of the Brystons' bottom end left me scratching around for answers. The vocals on the Fairfield Four's Standing in the Safety Zone (Warner Bros. 26945-2), while rich and full-bodied, were a bit too rich and full-bodied, needing a bit more fleetness of foot to really move along. Switching to Kimber Kable's KCAG digital interconnect tightened and opened up matters a bit, but did not completely eliminate the problem. The acoustic bass on King and Moore's "Man in the Oven," from Justice Records Sampler, The First Year (Justice JR#0002-2), was rather furry and ill-defined.

The Brystons' midrange and top end remained their strong suit. I got the impression over the course of time that the 7Bs' very highest frequencies were somewhat restrained—on "I Was Glad" from Magnum Mysterium (Chesky CD83) I wished for more of a sense of air and transparency. However, the consistent lack of any nasty surprises at the top were strong compensation. The Brystons' three-dimensional, natural midrange reproduction continued to be a delight. The sound bloomed in an almost tube-like fashion. And while I would not confuse the sound of the Bryston 7Bs with that of a good tube amp—it did not have the lively openness of the best of that breed—it still had some of that soft, sweet high end, glowing midrange, and, yes, overwarm bass that defines (and limits) the sound of tubes.

With analog program material (the above observations were made with Compact Disc as a source) the picture changed rather significantly. Much of the excess warmth dried up. This was a rather surprising observation, inasmuch as analog is often credited with being warmer-sounding than digital. My experience with a Clavis cartridge—a close relative to the more expensive Parnassus in the present system—does indicate, however, that this family of cartridges tilts more to the lean and tight than to the rich and full. As I am still scoping out the sound of the analog front-end used here, it's a bit early to totally pin down its inherent sound, but in fairness I cannot ignore the fact that the Brystons definitely sounded lighter on their feet with this particular analog front-end.

I used the digital front-end for the remainder of the evaluation because I am more familiar with its performance. The C.E.C./Levinson is a first-rate combination, but the C.E.C. transport is also slightly rich rather than analytical. A brief trial of the setup with the yet-to-be-reviewed California Audio Labs Delta transport did indicate a slightly cooler sound with the latter, though with a slight but noticeable sacrifice to that three-dimensional, grainless midrange heard with the C.E.C.

Krell Komparisons
To settle the matter—if not once and for all, then at least to my present satisfaction—I pulled out (footnote 2) our Krell KSA-250 for a side-by-side comparison with the Bryston 7Bs. This particular Krell model was discontinued earlier this year, but it's a Class A amp with which I have had a great deal of experience. The listening room took on a toastier ambience with the KSA cooking on all burners (the Brystons, unlike the Krell, run relatively cool), but I proceeded with the comparison regardless. Somebody had to do it, and all that.

I began with unbalanced inputs to both amplifiers, and the Brystons still in the parallel mode. With the Krell, the sound tightened noticeably. It was not quite as sweet-sounding overall as the Brystons, but was in no way lean'n'mean, either. The Krell's bottom end was tighter and more detailed, its potency a bit less obvious than that of the Brystons, but certainly not seriously lacking in that respect. "Man in the Oven" on the Krell definitely had a more defined, transparent quality, with a less warm but better focused acoustic bass. The extra warmth of the Brystons added a welcome warmth to the vocal, however, pulling it slightly more forward and imparting immediacy. The Bryston did display a touch of occasional brightness in the low treble here. This hadn't been evident when I auditioned it alone, but it was audible next to the more laid-back Krell. This was quite minor, however.

On the strikingly recorded "Under the Boardwalk" from Rickie Lee Jones's Girl at Her Volcano (WEA International WPCP-3710)—which is an early RLJ album that's not, to my knowledge, generally available on CD in this country—the Bryston brought a good sense of space and openness with its characteristically clean top end. The vocals were solidly set in space, both in width and depth. The sound was very dynamic and slightly forward, which suits this music perfectly. The bottom end here had solidity and drive. Only a slight hardness was noted at the conclusion.

Surprisingly—based on my experience with the two amplifiers to that point—the Krell only finished a strong second here, with the lead-in voices less spacious and differentiated, the highs a bit drier and less clean. The bottom end on the Krell, as before, remained tighter and leaner than that of the Brystons. This tended to open up the overall sound somewhat, but the bigger bottom end of the 7B was put to good use on this recording. Both amplifiers turned in first-rate performances here, but the Brystons took the checkered flag.

Overall, however, the balance of strengths on the WATTs/Puppies slightly favored the Krell, particularly with its more tightly controlled—if not always as big or impressive—bass. But the strengths of the Brystons continued to impress, and they presented a strong challenge to the more expensive Krell.

On the Alón IVs
To gain an additional perspective on the 7Bs' performance, I also auditioned them driving a pair of Acarian Alón IVs. The Alóns, still in their break-in stage, were less neutral through the midband and a bit more potent in the deep bass than the WATTs/Puppies. They also had a less finely rendered (though still very good) soundstage, and, I felt, a smoother though no less detailed top end. The Alóns are considerably less pricey than the Wilsons, though hardly cheap, and are more likely to be found at home in a system with the comparably priced Brystons.

My observations on the 7Bs through the Alóns were little different. The Brystons remained in the parallel mode. Their top-end response was still clean and detailed, yet at the same time silky and sweet. That bloom to the midrange remained. Imaging was excellent, though the Alóns were, as I noted above, a bit less holographic than the Wilsons, particularly in defining front-to-back-depth. The Brystons' slight lack of top-end air and more obvious low-end softness remained.

My notes comparing the Bryston 7Bs (still in parallel) with the Krell KSA-250, this time on the Alón IVs, also look like near copies of my earlier notes with the WATTs/Puppies. The Krell continued to have the less rich, more open sound. On the Rickie Lee Jones "On the Boardwalk" cut, the Krell came out ahead. At the very beginning of the piece, there is a hard-to-identify sound in the far background. On the Krell, it was more sharply defined, and while I still could not make out exactly what it was, it sounded like a young child saying something that prompts a chuckle from one of the musicians. With the Brystons it was still audible, but less clearly focused. The Krell also gave a more immediate sense of the recording space.

Listening to both the Krell and the Brystons with a balanced connection, I initially thought that the Brystons, if anything, were now a bit softer and looser—not a plus. But further listening indicated that the sound was essentially similar to that with the unbalanced link, consistent with my ongoing observations about balanced vs unbalanced connections when used for short runs in home audio. In another environment, perhaps, balanced operation might make more of a difference.

Despite some of my reservations, however, the Brystons were always a pleasure to listen to. That sweet top end and palpable midrange were powerful attractions, counterbalanced only by a slightly too rich balance and the lack of that last iota of transparency.

Conclusions & Further Thoughts
While they don't quite equal, in my judgment, the sonic performance of the very best amplifiers in Stereophile's "Recommended Components," a pair of Brystons will take a smaller bite out of your bank account. The Krell KSA-250, for example, is both less powerful than the Brystons (though this did not have audible consequences in my listening) and about $2000 more expensive. And the most powerful Krell stereo replacement for the KSA-250, the new KSA-300S, which I have not yet heard in familiar circumstances, will cost over $3000 more than the Brystons and still have a lower rated power output.

While I felt that the warm, full quality of the Brystons was their main limitation, others aspire to this quality in their systems, provided it is not taken to unnatural extremes—which the 7Bs certainly do not. When DO heard the Brystons in my system—though admittedly with an additional variable in the form of the California Audio Labs Delta transport and new Alpha D/A converter—he remarked that the WATTs/Puppies sounded better than he ever recalled hearing them in the Stereophile listening room. That's certainly not to be ignored, considering that Thermionic Dick heats his room with tubes.

Nor can I ignore the fact here that the Stereophile listening room tends to a warm sound. The Brystons' inherent warmth would likely be less of a problem—perhaps even a benefit—in a larger and/or cooler-sounding room or system. And its rich, tactile midrange and clean high end would be a benefit anywhere.

A Class B call here, in my opinion. Among the strong contenders in this class, both the Aragon 4004 Mk.II and the Hafler 9500 will, I believe, give you a more lively, immediate sound, but one that is less sweet and subtly refined.

Our recommendation that you listen to any high-end amplifier you are considering in your own system holds true here as much as ever. But if the 7Bs lock into your room/system, you won't regret their purchase.

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Footnote 2: Actually, one does not ever "pull out" a Krell.