Authorized pre-print of:
The Inner Ear Report
Volume 15, #2
www.innerear.on.ca

Source: Bryston Ltd.
Rating :

Bryston is an electronics manufacturer that has been successful in the consumer and professional electronics industry for decades and enjoys an immaculate reputation in both markets. In fact, during the last couple of years, Bryston has produced what we consider to be some of the best solid state audio amplifiers currently on the market - the 14B SST and the 7B SST monoblocks. The amplifier and preamplifier under review are Bryston¹s newest designs and are aimed at the high-end home theatre market where function and features combine with performance. This said, let's get to the components' ...

Appearance:

Both, the power amplifier and the preamp/processor present a clean, refined look that offers functional features, rather than meretricious physiognomy. Both our samples came in a brushed aluminum silver finish which blends harmoniously with the units' indicator lights. The SP1.7s' faceplate accommodates (from left to right) an LCD status display window under which the designer has placed a small toggle switch (on/off), followed by the standby LED, the infrared sensor for the remote control and a three-position toggle that controls dynamic range for Dolby Digital™ encoded bitstream signals. Three menu control buttons for set-up navigation are followed by six source selection buttons (TV/Sat, DVD, CD, Aux, VCR and Tape) and a row of seven mode function buttons and corresponding LEDs. A small balance control knob and a large volume control compete the preamplifier¹s front panel layout.

The component measures 17 inches wide, 13.5 inches deep and 3.8 inches high and weighs about 22 pounds. A rack mount version is available.

The 9B SST's faceplate accommodates the touch sensitive on/off switch in the centre and just above it, a row of five LEDs (one for each channel) to indicate status (green, yellow and red). On the unit¹s rear panel, a switch allows the option of balanced inputs (XLR or 1/4" phone jack) or unbalanced inputs (RCA). The inputs can be switched to allow different gain settings. The amplifier measures 19 inches wide, (a 17" version is also available) 5 1/4 inches high and 19 inches deep. It weighs in at a whopping 65 pounds. Rack mounting option also is available. In all, these components are quite captivating and will appeal to the style conscious as well as to the professional.

Technology & Features:

The SP1.7, though loaded with HT features, has its design origin firmly rooted in two-channel audio and its considerably tougher standards. According to Bryston, the SP1.7 was designed to provide state-of-the-art "audio" for 2 or 5.1 channel analogue playback or digital 5.1 to 7.1 movies.

For starters, the unit has no video switching on board as video switchers operate at very high frequencies (RF) and elevate noise. Like amplifiers, video switchers have different quality levels and it is wise to allow the quality of an outboard video switcher to match the rest of the system (video is changing rapidly and it is not yet clear which direction the industry may take; i.e. composite vs S-video vs component vs Firewire etc.). Bryston is currently marketing their own SPV-1 Video Switcher which can be connected to the rear of the SP1.7 and can also be used with other processors available on the market. The other option is to switch video at the TV or projector, as most units now offer plenty of video connections (provided internally) for use with a universal remote control that allows switching audio and video together.

To keep the design within accepted high-end audio-only standards, Bryston¹s designers opted for two well isolated toroids (one for the analogue circuit, the other for the digital circuit), without digital power supplies as these are also RF generators causing noise.

The SP1.7's volume control has two parts to allow the analogue signal to function independently from the digital signal. Analogue audio is kept free of digital interference by activating the "by-pass" mode. It's interesting to note that, while quite a few processors feature a "by-pass" setting, most use the DACs to raise and lower the volume level‹clean, but digital. All in all, great care has been taken to assure performance in line with audio-only criteria, while also handling all other formats such as "audio" analogue playback for 2 or 5.1 channel or digital playback of 5.1 to 7.1 movies.

The specifications are impressive: frequency response is from 20Hz to 20kHz, with THD at less than 0.006% in DSP mode, less than 0.0025% in by-pass mode; S/N ratio is 105dB in DSP modes, 110dB in 2-channel by-pass mode. Bass management is achieved with 2nd order HPF (x5), 4th order LPF with crossover frequencies from 60Hz to 220Hz. A/D conversion is done with Delta Sigma (system configuration) 24-bit, 48kHz; D/A conversion is achieved with Delta Sigma 24-bit, 96kHz. The Motorola 56367 is the DSP engine.

Now to the 9B SST power amplifier:

This amp belongs to the new series of SST components which feature many improvements over the older series. These include faster, more linear and more reliable output transistors to improve high frequency precision, doubled filter capacitance (for deeper and better-controlled bass), a new proprietary grounding arrangement that eliminates the need for ground-lift switches and reduces system noise, and a new computer-modeled heatsink for cooler operation (and longer component life).

All analog circuitry is fully discrete to avoid the phase shift and non-linearity inherent in IC's. This and other SST models feature an innovative gain stage topology, which results in a remarkably low noise floor perhaps the reason for the system's ability to render astounding clarity. Custom, totally independent and separate torodial power transformers are used for each channel of amplification. The power supplies boast multiple filter capacitors for each channel, rather than single pairs of larger filter cans. This is said to improve high frequency response and maintain stability.

Specifications:

Power: 200 watts/channel into 4 ohms; 120 watts/channel into 8 ohms. Distortion: <0.007%from 20Hz to 20kHz IM or THD+noise is <0.005% from 20Hz to 20kHz at rated output into 8 ohms; signal to noise ratio from 20Hz.to 20kHz ranges from -110dB to -116dB; the slew rate is greater than 60 volts per microsecond; bandwidth ranges from less than 1Hz to over 100kHz; damping factor is over 300 at 20Hz; ref 8 ohms.

The Sound:

As we do with all two-channel audio system evaluations, we inserted the SP1.7 into an existing set-up, first connected to some of our in-house power amplifiers. The Gershman Acoustic X-1s/SW-1 (reviewed in Vol. 12 #2) served as our auditioning loudspeakers and the Audio Aero Capitole CD player (reviewed in this issue) was used for the audio-only tests. Speaker cables and interconnects were supplied by XLO and Nordost‹Limited Edition (reviewed in this issue) and Valhalla (reviewed in Vol. 13 #2). As we were intimately familiar with all peripheral components, auditioning the SP1.7 in its audio-only mode was relatively simple.

In the HT mode, we connected the SP1.7 to the 9B SST power amplifier to drive the Gershman Acoustics front, centre and surround speakers and a subwoofer, wired with Red Dawn cables. Between amp and preamp/processor, we used balanced interconnects supplied by Bryston. An upscale DVD player and a VCR were used as source components. We used DVDs with familiar program material ranging from sophisticated, subtle soundtracks to out and out dynamics, such as crashes, shots and other bone-jolting information. The system set-up and, later, the fine tuning, was achieved with the help of the cable TV signal, with the monitor¹s screen switched off. This prevented us from being unduly influenced by the visual stimulus when setting up the SP1.7's parameters, achieved by employing the built-in pink noise generator, a sound pressure meter and our ears, of course. It turned out that the unit¹s default settings were almost right for our listening room and only small additional adjustments were required before we fired up the DVD player with a movie that contained the various, aforementioned, sonic elements. The processor literally shone as it extracted subtle, difficult to notice (or appreciate) sounds, commonly found in dialogue and background murmur, almost out of, but absolutely within the range of audibility. The SP1.7 accomplished one of the most important elements of audio-only information by revealing "inner detail". Upon closer investigation, we established that the unit¹s low noise floor is likely responsible for the first-rate articulation of subtle material. Tracking Dolby Digital® and Pro-Logic II® is done with that certain freedom from constriction that results in relaxed, realistic sound that allows dynamics to coexist with soft, quiet data. All that is achieved without emphasizing (or degrading) sound across the audible frequency range. In the DTS modes (both DTS 5.1 and DTS-ES 6.1), the processor decodes the signal without added post-processing! and it does so without limiting any important functions.

The 9B SST power amplifier is another serious component and, for this review, provided muscle and vitality to the all-round sound. For our tests, we bombarded this amplifier with difficult-to-handle information and found that it can not be subdued by overproduced dynamics, often found in film soundtracks such as End Of Days and similar melodramatic movie soundtracks. The 9B SST handles dynamics with staggering reality and without effort. This multi-channel amplifier sounds very close to our in-house 7B SST monoblocks which is to say that it offers smooth, but well-culminated highs, unimpeded midrange and solid, deep-reaching bass. We operated this amplifier in the audio (stereo) mode using the SP1.7 in the by-pass, preamplifier mode, and a pair of Gershman Acoustics X1's with passive subwoofers and noticed the system¹s ability to throw a wonderfully multi-dimensional sound-field. In terms of pure audio, multi-dimensional means depth, width, height and time/space all elements that high-end systems are better equipped to accomplish. The 9B SST/SP1.7 system managed to achieve all aforementioned action, succeeding where most home theatre components do not. The overall sound wasn't as warm as that of the 7B SST monoblocks, but we noted similar speed and dynamics without exaggerating kinetic energy and well within the performance characteristics of high-end audio.

Synopsis & Commentary:

In a consumer electronics market where home theatre sales dominate and systems are available at ridiculously low prices, it is good to see that some companies haven¹t lost interest in quality and performance. A serious HT set-up should perform as well as a professional installation in a movie theatre, perhaps even better because synergistic component matches are readily available and allow the end-user to customize the sound to the highest attainable degree. We feel that the Bryston components offer optimized ³synergy² of amplifier and preamp/processor the system's power and nerve centre. Some time ago, we decided to employ the full-range Gershman Acoustics loudspeakers for most of our HT component evaluations, because we found that they offer enough tonal neutrality to reveal the function of the electronics‹and, except for the centre channel, they adhere to audio-only standards. For this evaluation, they proved to be a good "synergistic" and compatible addition in both the HT and audio-only modes. Nevertheless, there may be as many as one hundred brands that will also qualify as "compatible" but this is where personal taste must prevail as a system must please only one set of ears‹yours.

We believe the Bryston HT system offers unadulterated potency reminiscent of a caged animal waiting to be set free‹confined energy waiting to be released. Unlike a wild animal, however, the sound, once liberated, is well tempered. The system has dynamic reach, but behaves within the realm of authenticity, likely as a result of the preamp/processor's ability to govern the system's parameters without obstructing the original signal from the source components. While we were quite impressed with the 9B SST power amplifier, we were flabbergasted with the quality of the processor/preamplifier. The preamp section is likely the best Bryston has manufactured and the processor is state-of-the-art; this is home theatre as good as it gets. Needless to say, it is advisable to use upscale source components, good wiring and conscientious set-up procedures. Then sit back and enjoy some of the best home theatre experience since the beginning of multi-channel audio.

We invite you to experience the Bryston SST² Series amplifiers

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