Authorized Re-print of:
The Inner Ear Report
Volume 7, #4

Bryston Amplifier Model 3B ST Bryston has been around for a long time and, contrary to common belief, the company has been catering to aspiring audiophiles as long as they have been in the professional field. Its been about four years since Bryston brought us new models of the 3B NRB and 4B NRB. With the new models, the designation NRB has been dropped and a rather visible ST designation depicts the current design. Bryston has always been a rather conservative company who doesn't jump on trendy new technology and the ST series came as somewhat of a surprise to us. However we know that the company has devoted a lot more energy to research and development of new technologies, the sum total of is the ST Series amplifier.

Appearance

Nothing much has changed and at first glance, the amplifier appears to be the same as the previous model. The faceplate is beautifully styled and offers a classic look which almost became Bryston's trademark. A pair of handles reminds us of Bryston's world-wide involvement in the pro market. An On/Off switch and two small LEDs blends well in to the frontal appearance. The rear of the amplifier accommodates RCA inputs as well as balanced (XLR) inputs. A small self-cleaning side switch allows selection of the inputs. Another switch serves as a ground selector whereby the signal ground can be floated from the chassis ground. Another slide switch allows stereo or mono operation. A detachable power-cord connects to a push/lock holder which accommodates the fuse. A pair of five-way binding posts completes the units rear panel. The amplifier weighs twenty-two pounds and measures 19 x 5 1/4 x 9 inches.

Technology

The 3B-ST is made up of two amplifier modules which employ four output transistors per channel -- eight in all. Two power supplies rated at 55 volts each have been employed The ST-Series amplifier offers a number of improvements. There is a special buffer-with-gain at the amplifier's input, which addresses a number of important parameters. It isolates the source from the non-linear input impedance of the amplifier's input. These impedance variations are tiny, but still measurable and can add distortion to the input signal. In this design, the signal within the amplifier is conducted at a very low impedance to eliminate most, if not all of the noise that's added by the amp circuitry. It's done with a split gain function between two low-feedback elements to reduce distortion below that of a single-element path. The power supply differs from the earlier model as well. Special printed circuit boards and connector technology virtually eliminates wiring in the signal path and prevents unit-to-unit variability and signal degradation in cabling. The amplifier circuit has been refined to drop distortions at high frequencies by more than 50%. With the ST-Series, Bryston has achieved new standards for low distortion and a noise floor ten times lower than that of the best digital signals. Our model has been bench tested with following results: Total harmonic distortion at full power -- no more than 0.00556% Intermodulation distortion (60 Hz to 7 kHz) -- no more than 0.00168% Power at clipping (8 ohms) -- 152 watts Noise 20 Hz to 20 Hz, input shorted in dB below rated output -- minus 108 dB

The Sound

The brand new unit, just out of the box sounded quite good although it hadn't been burned in by us (Bryston operates each amplifier for one-hundred hours to burn it in). We connected the 3B-ST the PMCs, reviewed in this issue, tuned in to an FM station and let it play for about three days, before we settled into the first listening session. The most apparent trait -- if one could call it that -- is the amplifier's knack to resolve inner detail. Whereas the highs sounded extremely smooth with the NRB model , the ST comes across more detailed with a better reach into the upper ranges. The ST's entire midrange area exhibited a more detailed character then the previous NRB model -- which lends the amplifier a revealing and resolving quality rarely found in amplifiers in this price category. The mid-base area of the amplifier has much the same quality as the region above. These characteristics lend the unit an uncanny tonal equilibrium and may be responsible for the excellent presentation of inner detail. In one of our tests, we connected the amplifier with a pair of our in-house Ethera Vitae loudspeakers. The Ethera have that certain sonic sophistication to correctly manage (play back) characteristics of amplifiers. As well, we have had a 3B-NRB in our studio for about one year so that we can find compatible equipment for components under review. The system is well known to our listening panel and all we had to do, was insert the 3B-ST where previously the NRB had been used. We did just that and this turned out to be quite an experience. Whereas the NRB model hinted at some hardness in the upper frequency regions, the ST model remained much more refined, yet utterly revealing. We evaluated the base and compared it with the NRB; and again, the ST outperformed the earlier model, distinguishing itself with a richer, more robust mid and low base performance. Finally, and not immediately noticeable, the 3B-ST offered a better defined sound-stage, specifically, the front-to-back information is more apparent and the image depth is improved. This sort of refinement isn't overwhelming and some of our panelists didn't notice it until the more experienced listeners pointed it out. It is possible that the amplifier's subtle revealing quality, the lowered noise floor and the smooth sonic quality made the previously mentioned image more apparent.

Synopsis & Commentary

Bryston is a relatively conservative company which doesn't come up with new "improved" models every year. Traditionally, Bryston will not touch that which hadn't been successful and hadn't proven its value in the market-place. The new ST series had been quietly developed and its technology had been implemented in the model 8B before the company made the decision to change all of their designs. In other words, the ST series has already been tested in the applications around the globe. In all of our tests, the 3B-ST exhibited an improvement over the NRB model. The all-round sonic character of the new 3B can be described as refined, very detailed and certainly musical. The old NRB model; has been one of our favorite amplifiers in the lower wattage range -- if one can call 120 watts "lower wattage". However, the 3B-ST -- while not dramatically different -- offers improvements not related to dynamics, more power or more refinements in one specific area; it supplies better all-round sound, best described as more sonic sophistication. We feel that the 3B-ST's performance/price ratio is astounding. Add to this, Bryston's twenty year warranty, and there isn't a doubt the 3B-ST amplifier comes in as a bargain since we are getting a high resolution amplifier at a relatively low price.

We invite you to experience the Bryston SST² Series amplifiers

20 Year Warranty - A Generation of Music