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Bryston PowerPac 120
It could be said that these amplifiers are indicative of future developments as the audio/video industry develops into a consolidated media system. What we have here are two monaural Bryston 3B-ST amps which can be mounted on the rear of loudspeakers, or placed on the floor near the speakers. This approach allows for the shortest speaker cable run to the loudspeakers' terminals, but involves long(er) interconnects-really the classic audio component setup. If the amplifiers are mounted on the rear of the loudspeakers, they add mass to the enclosures-which is an additional benefit, because it helps to diminish vibrations. When your system's front end-the preamplifier and source equipment-is close to the listening position, you'll need long interconnect runs. If, on the other hand, the front-end components are close to, or placed in the middle of the loudspeakers, the chance to pick up interferences from the amps is somewhat greater. It is recommended to place the preamp and source components well away from the power amplifier(s).

Appearance:

The two amplifiers are rather small measuring only 12 inches long, 7 wide and 4 inches high. They weigh about 16 pounds each. The chassis has been designed to accommodate the amplifier's heat-sinks and its mounting arrangement. The units can be mounted almost anywhere, even in small spaces. There is a ground-lift switch, an on/off switch, a level control (29 to 13dB), a fuse and a detachable power cord. RCA and XLR connectors and five-way speaker terminals complete the amplifier's design.

Technology:

Fundamentally, the mono amplifiers are left-and-right-channel components of the popular 3B-ST stereo amplifier and, like the 3B, employ four output transistors in each unit. The power supplies are rated at 55 volts and are designed to eliminate most wiring in the signal path. A special printed circuit board and modern connector arrangement provides the shortest means of signal transfer. A special buffer with gain at the amp's input addresses a number of critical elements. It isolates the source from non-linear amp input impedance which can add distortion to the input signal. The signal inside the amplifier is conducted at a very low impedance to eliminate most of the noise added by the amplifier's circuitry. This is accomplished by a split gain function between two low-feedback elements which reduce distortion below that of a single-element path. This and other techniques effectively produce an amplifier which reduces distortions significantly at high frequencies. The end-result is a unit which offers the refinements and resolving capabilities of usually higher-priced-often more powerful-amps. This brings us to...

The Sound:

It has always been our opinion that the 3B-ST is Bryston's statement amplifier. It offers refined sonic characteristics in line with much more expensive units. At 120 watts (per channel) the amplifier doesn't offer a lot of slam, but it delivers exemplary finesse with sparkling highs, finely etched inner detail, fully resolved bass and great tonal equilibrium. Similarly the PowerPac 120 amps, have one of the lowest noise floors in the business, which may account for their uncanny image retrieval. In fact, the imaging is a touch better than the 3Bs, particularly in front-to-back layering and focus on instruments and voices. It's speculation on our part, but it may be because of the power supplies' proximity and the elimination of inter-channel reaction that we perceived the slightly improved imaging quality of the PP120s. Stunningly clear highs, striking midrange, and robust, well-resolved bass complement the all-round presentation of sound/music.

Synopsis & Commentary:

The idea to connect the amplifier directly to the loudspeaker isn't new and dates back to the sixties. Monoblock separates have also been on the market for quite some time, but the industry at large ignored the piggy-back method, unfairly so in our opinion. Most monoblocks perform better because of the separated power supplies and components. The PP120's, yes, of course, they are monoblocks - mountable monoblocks, that is. They can be mounted on a wall, in a wall, or on the rear of loudspeakers, making them versatile in applications such as home installations, home theatre setups and as part of multi-amp systems. We have no idea why it took the industry so long to re-introduce this rather efficient method of amplification. Placed out of the way, the amps can't be seen, fulfill the same function as a typical stereo component and offer sonic advantages to boot. It may be of interest to our readers to learn why Bryston came up with the design and what prompted them to offer this rather pro-audio approach to consumers.

Bryston's distributor in the U.K. is also the manufacturer of the PMC brand of loudspeakers and for some time now, they have sold their PMCs with Bryston electronics, which they believe to be a match made in heaven. For convenience, most PMC models offer predrilled mounting threads on the rear panel of their speakers. They registered great success with this arrangement which encouraged Bryston to explore the potential with other loudspeakers. So, if and when you are in the market for a new amplifier, you should consider the PP120s instead of a single amplifier. As always, hearing is believing and you must listen for yourself. The PowerPac 120 amplifiers have our blessing and you may agree with us as soon as you have auditioned them.

We invite you to experience the Bryston SST² Series amplifiers

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