August 1999 Bryston 4B-ST Amplifier by Jon Gale

A high-power amp with refined sound and a reasonable price tag.

High performance. We expect this term to imply faster, stronger and more efficient. But what does it mean to us audiophiles? A not altogether improper analogy can be made to racing. In my 20s, I fell in love with sport motorcycles, so much so that I decided to try my skill in the club-level road-racing scene. I soon came to find that the "box stock" class is anything but. Engine blue-printing and intake and exhaust modifications are the rule. Throw in performance running gear and rubber, and it starts to make audio look sane! Unfortunately, a funny thing happened along the road to high performance. In essence, I took a wonderful broad-focus, "streetable" motorcycle and transformed it into a fire-breathing, single-purpose, unforgiving racing bike. Riding it on the street was a lesson in futility. Its single purpose was to go, turn, and stop as swiftly as possible.

Lately I have been thinking that high-performance audio, in its quest for ever higher resolution, is leading us down this same narrow path. Countless times I’ve auditioned a sparkling new component only to find that although the performance is wonderful on my 12 or so puuuuurfect discs, the playback of more real-world recordings leaves me wondering where the music has gone. This quest for resolution results in every component in the chain being a highly refined microscope instead of a messenger of music. This is progress?

Of the many ways one can go about assembling a reference system, I tend to choose a method that is both straightforward and, for me, possesses the most common sense. I assemble, within my given budget, the most neutral-sounding electronic components of my choice. I will then use the choice of speaker, arguably the most variable of all components in a system (excluding the room of course), to achieve the final voicing of the system. This is not to imply that the speaker is the most important link in the chain, however. As one sour choice in electronics soils everything downstream from that component, I prefer to have any anomalies or distortions to be at the end of the chain. This is certainly not the way -- just my way.

Heeeeere’s Bryston

Until the arrival of the 4B-ST, I had never had the chance to hear any Bryston amplifier, although I had a Bryston 10B electronic crossover in my system for years with very good results. As the 10B seemed to have very little of the oft-rumored pro-sound quality, I was very intrigued to hear what Bryston could do in the area of high-end amplification.

The Bryston 4B-ST is a quite handsome little devil in its own modest way. While at this price level one mustn’t expect audio jewelry, Bryston does a nice job with a few machining touches to enhance the basic black-block look. At 19"W x 14 1/2"L x 5 1/4"H, the 4B-ST is not a room-filling monster by any means. Sporting nicely beveled handles and two 45-degree chamfers running the width of the amp, the 4B-ST has nice business-like cosmetics that shouldn’t intrude on any décor. The front panel consists of a power switch with two green LEDs above it, nestled in the top groove. These LEDs are said to be three-color units to warn of clipping or its onset. I use "said" because never in use could I get them to turn orange (onset of clipping) or red (clipping).

Rated at 250Wpc (8 ohms) and up to 800 watts bridged (also 8 ohms), the 4B-ST never seemed to run out of steam even at some raise-the-roof levels. Further, specs imply good engineering and a stiff power supply. Distortion is at less than .007% from 20Hz to 20kHz, with a slew rate greater than 60 volts per microsecond. (120 volts per microsecond bridged). Coupled with a damping factor of over 500 (at 20Hz, reference 8 ohms), this is a good recipe for woofer control.

Other features include a stereo/mono switch, gold-plated input/output connectors, and switchable balanced XLR and RCA single-ended inputs. One nice feature I would like to see more of is the ground-lift switch. This lifts the internal circuitry while still grounding the chassis. As I noticed a slight ground-loop hum upon hook up, a flick of this switch resulted in a dead-quiet background.

What became immediately apparent during setup was the need for an industry-wide standard for connection devices. I’m specifically referring to the 4B-ST’s speaker binding posts. These beefy posts have a protective shroud over them per a Canadian mandate. It’s said to eliminate a short circuit problem if you drop something between the outputs. I ask you, when was the last time this happened to you? Trying to hook up the new MIT MH-750 speaker cables (review in the works), I found the supplied spade connectors too small to fit the posts. No problem says I, a great chance to work with the new Icon connector system MIT has devised. I simply unscrewed the small spades and mounted the larger versions. Ah, not so fast Audio Boy, now the spades were too thick to insert into the protective shroud! After much cursing about the litigious society we live in, I had to settle for using Monster Cable banana plugs on the MIT. This wasn’t a problem only with MIT, however. The manufacturer of a speaker under test suggested best performance would be obtained with Cardas Neutral Reference cable. Alas, the Cardas spades were also too thick to be accommodated by the protective shroud.

Sorry Bryston, but owners of kilobuck speaker cables won’t look too kindly on having to re-terminate them, so these shrouds need to be retooled with a larger gap to accommodate the thicker series of spades hitting the market.

Sound

Instantly evident was the fact the 4B-ST was the master of whatever transducer was down-wire. In removing the B&K Sonata monoblocks and inserting the Bryston, the sense of authority, or "room lock," in the bass and the overall dynamic control were significantly heightened.

Driving my (departed) reference Alón 4 speakers, the 4B-ST’s high-current delivery and damping factor ameliorated to a good extent the Alón’s upper-bass looseness. This bass anomaly has always been problematic in my concrete room, coincidentally coupling with a major room mode so as to make positioning particularly troublesome. I have effectively dealt with this problem by crossing over (at 80Hz) to a Vandersteen 2Wq subwoofer. Driven by the 4B-ST, the Alóns became very listenable when run full range, transforming a noxious bass hump into a controllable peak. It was during a particularly raucous listening session my friend Gary (Dr. Pizza to you), an unapologetic Krell man, exclaimed, "Now THAT’S a nice little amplifier!" As this session became an audition for the eventual buyer of the Alóns, we culled many of the bass torture tracks in my collection for play at decibels far above my normal listening levels. The "little" Bryston never cried foul, delivering tight, and suprisingly good ambient retrieval well into the deepest bass.

Towards the end of the review period I added the Vandersteen 2Wq subwoofer to the mix. This unit is not powered directly from the main amp, but is configured to take the high-level signal from its binding posts. The signal is then said to take on the character of the driving amp. As I have never put too much weight in this claim, I was surprised to hear a clear improvement in the sound of the sub. (Don’t you love being proved wrong at times like these?) Deep bass notes were loading the room with much less hangover, with the lower-register-piano and strung-bass notes showing more delineation.

In regard to the 4B-ST’s pro-sound heritage, I was anxiously suspicious of the mid/treble performance, specifically tonal voicing. I was curious to see if there would be vestiges of hardness or brightness. The first criterion of any product I audition is its intrinsic tonal quality, especially the upper octaves. As I have religiously (some say maniacally!) protected my hearing all my life, I find myself extremely sensitive to the voicing in this region. (Performing lawn maintenance, use earplugs. Power tools? Ditto. ANY concert, nightclub, bar? You figure it out.)

I found the tonal voicing to be near spot-on for my biases, seemingly delivering the signal presented at the inputs undiluted. Detectable was a slight, and I do mean slight, whitening of overtones in the upper midrange, accompanied by a once-again-slight drying of ambience in the treble region. On some pop material, there did seem to be a slight lift in the treble response, nothing noxious mind you, but perceptible. Utterly clear with exceedingly low distortion? Yes. Bright? Certainly not.

Detail retrieval was quite good. Listening to Reference Recordings HDCD Sampler, [RR-S3 CD], I found that the system-bending cut "The Vikings" was full of ambient bloom while capturing the wonderful bleat of the horns. The immense control of the speakers exhibited by the 4B-ST was shown to good measure in the dynamic peaks of this movement. (And peak this movement does! Bravo Prof. Johnson!) I find detail retrieval and tonal balance to be closely intertwined. It is very easy for a manufacturer to voice a product a little hot in the upper octaves in order to fool the listener into perceiving added detail. Such forced detail usually results in long-term listening fatigue. On the contrary, Bryston has addressed detail resolution through the (near) elimination of linear/non-linear distortions.

Quite capable performance was to be had in the area of imaging. While the 4B-ST just missed the separation of my (departed) B&K monoblocks, I found it interesting that image bloom, or rather the sense of the recorded venue encompassing the listener, was actually improved. I attribute this to the lack of bass smearing in the stiff power supply, much like the way a bass trap affects the room acoustic, in that it unmasks previously hidden low-level information.

It was in the area of depth presentation that I found the 4B-ST’s only major shortcoming. When compared to some other heavy hitters that I have experience with (granted, in different room and systems, but those in which I’m intimately familiar), depth does seem mildly foreshortened. Suprisingly, the rear of the soundstage expanding into the corners was noticeably improved. In all honesty, this is the first time I’ve heard this in my room. Using the aforementioned HDCD Sampler, "Behold Man," featuring the Turtle Creek Choral, there just wasn’t the sense of volume in the hall that other amps have projected in my room.

In my yearlong search for new amplification, two relatively recent visitors that have spent time on the floor were the McCormack DNA-1 and the Balanced Audio Technology VK-200. All three amplifiers were startlingly alike, although with subtle differences discovered over long-term listening. Each offers decidedly high value and will certainly have an audience. Of the three, the DNA-1 was the most sonically aligned with the Bryston, displaying a vice-like grip on the bass, although with a slightly forward upper midrange for my biases. The BAT VK-200 was voiced beautifully in the upper octaves, but had rather soft, undynamic bass response. I found the happy middle (as with Goldilocks) was the Bryston 4B-ST.

Rich man’s Adcom or poor man’s Krell?

The title of this segment was actually tossed out during an extended listening session with friends. Alas, the flippancy of this remark does not convey the real value of the Bryston 4B-ST. I feel the 4B-ST occupies a market niche that should strike fear in opposing camps. Priced squarely in the upper/middle price range, its performance is on a par with the big guns, sacrificing little of their refinement. Even more enlightening is the fact that this level of refined performance is brought to market by a decidedly non-tweaky manufacturer. If you are in the market for high-current, refined amplification, the Bryston 4B-ST should be on your proverbial short list. It was on mine, and I didn’t cross it out. But about those binding posts….

Concerning SoundStage!’s Reviewers' Choice appellation, readers will find me to be discriminating in the extreme. That said, on this combination of refined performance, tank-like build quality and high perceived value (with a 20-year warranty), I unhesitatingly bestow the honor.

...Jon Gale
jon@soundstage.com

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