Bryston
9B SST THX 5-Channel Amplifier
Truth in reporting – I am a fan of Bryston amplifiers, though I became one for the right reasons: when I opened my multiroom commercial studio I had 12 power amps throughout the facility: ten were new and two of which I purchased from a studio closing sale. Those two were Bryston 4Bs, five years old.
When I sold the studio ten years and thousands of recording sessions later, the only amps that had not become dodgy or died outright were the Brystons, which had shown no signs of anything other than steady, reliable clean performance. A call to the current studio owner confirmed what I already knew – five more years on and the Brystons are still going strong, sounding great.
Based on my fondness for the amps and the fact that I have been mixing in surround more frequently, I jumped at the chance to check out the Canadian company’s update on the five-channel 9B ST amplifier, re-dubbed the 9B SST THX .
Features
The Bryston 9B SST THX is a modular, 5-channel, single-chassis power amplifier that delivers 200 Watts per channel into 4 Ohms or 120 Watts per channel into 8 Ohms.
The 9B SST employs modular construction in which each channel is completely self-contained physically, and electronically, with independent I/O connectors, toroidal transformer and independent power supply. The only things individual channels share is the rack enclosure and the power cord.
Each channel is built on its own removable assembly, allowing any channel to easily be swapped out, and enabling the 9B to be configured with fewer channels if required.
The 9B may be ordered in two to five-channel versions, with the five channels as standard. Additionally, any two of the channel modules in a 9B may be run in bridged configuration with an accessory cable.
The 9B SST THX is an update of Bryston’s original 9B ST five-channel amp, introduced over five years ago. As far as circuitry is concerned, it appears that Bryston kept the new amp essentially the same as the well-regarded original, making only minor changes to improve already excellent specs and adding a few theater/THX-related elements.
Changes include a doubling of filter capacitance and the use of highly linear, output transistors to improve already excellent high-frequency accuracy. Bryston also implemented a proprietary grounding scheme that reduces overall system noise and added some bits to receive its THX compliance.
The clean front panel features five LEDs that indicate operating status and five small recessed gain adjustment pots; a membrane power switch is located in the bottom center of the face plate. A rear panel toggle power switch doubles as circuit breaker reset (no fuses). The amp features soft start power control circuitry to eliminate high inrush currents when A/C power is applied. Power up of the 9B SST may be controlled by external components such as a preamp via rear-panel 12-volt input.
The rear panel is where all the action is. Each of the five modules includes: an input select switch for choosing balanced input or single ended input; a combo XLR-1/4-inch balanced input connector and a unbalanced input on RCA; a polarity switch for inverting the polarity of the input signal -180 degrees; a three position input sensitivity switch selects 1 volt (THX home theatre standard for unbalanced inputs), 2 volts (for actively balanced inputs), and 4 volts (for use with high output level preamps); and a heavy-duty three-way binding post that accommodates banana plugs, spade lugs and stripped wire up to 3 gauge.
The rack mount enclosure measures 19 x 5.25 x 19 inches and weighs a hefty 65 pounds. Maximum power consumption is
220 Watts at idle and 2295 Watts at rated output into 4 or 8 Ohms.
According to the manufacturer’s specs, distortion is less than 0.007 percent from 20 Hz to 20 kHz at rated output into 4 Ohms. THD + noise is less than 0.005 percent from 20 Hz to 20kHz at rated output into 8 Ohms.
Signal to noise ratio (Measured with input shorted; 20Hz. to 20kHz.) is greater than 110 dB at 29 dB gain (-75dBu) and greater than 116dB at 17 dB gain (-78dBu). Slew rate is greater than 60 volts per microsecond and the power bandwidth runs from less than 1 Hz to over 100 kHz.
In use
I used the amp for a month in two environments with different objectives: multichannel mixing in a studio control room, and multichannel playback in a high-end home theater setup.
In the studio, hook up of the Bryston 9B SST THX was straightforward.: two digital audio workstations (Pro Tools Mix Plus through a Digidesign 24-bit optical interface, and Steinberg Nuendo/Sonic Foundry Vegas system through a 24-bit RME 9652 interface) were already routed into a TASCAM DS-M7.1 surround controller; five XLR monitor outs were patched into the Bryston amp and out to the speakers (see review setup below).
In the studio environment, I mixed several 24-bit/48 kHz multichannel music-only projects. Halfway through the evaluation, I added the Nuendo and Vegas system and was able to complete a few projects at 96 kHz, including music-only and sound design/multichannel mastering for video.
Without getting into too much audiophile adjectival mumbo, the amp performed and sounded like a Bryston: strong, clean and uncolored, and with a surprising amount of headroom at just 120 watts per channel into 8 Ohms. The amp handled wide dynamic changes impeccably, and there was no perceptible crosstalk.
After a month, the amp was moved into my home theater for more, ahem, relaxed evaluation. Here, I could concentrate on the performance of the amp without distraction.
Many music-only and theatrical DVDs were auditioned through the Bryston 9B SST THX. I used the multichannel outputs directly from the DVD player’s surround decoders and through a Denon AVR-3300 acting as a preamp. There was a slight narrowing of the image and some added “fuzziness” or veil through the Denon’s preamp, decoders and/or D to A. The moral here might be: “The less things between the source and the amp, the better.” Or: “Time for a new preamp.”
With the preamp out of line, the amp performed as above: powerful and dynamic with excellent imaging
Summary
I’ve always felt that playing back music through a Bryston sounds close to what was happening in the studio mix session. That’s possibly because it was mixed on a Bryston; or maybe it’s because it doesn’t get any better when it comes to unfettered neutral and dynamic reproduction.
But it does makes make me wonder why people in the audiophile market are willing to pay tens of thousands of dollars for an esoteric single-ended triode amp (because it’s more soulful, musical; warm yet not limp; up front but not overly urgent…) when they can have the real deal for just a few thousand.
For both studio and home theater use, the Bryston 9B SST THX amp is worth every dollar – a true pleasure to work with professionally, or to simply sit back and enjoy.
Review Setup:
Steinberg Nuendo and Sonic Foundry Vegas DAW with TC Works Powercore; Pro Tools MixPlus DAW; SP Technology Timepiece 2.0 and Westlake LCW 8.1/4.75 monitors; Audience high-resolution speaker and audio cables; TASCAM DS-M7.1 surround controller.
Applications:
Studio, postproduction, theater and installation
Features:
Modular, 5-channel power amplifier; 200 Watts per channel into 4 Ohms or 120 Watts per channel into 8 Ohms; swappable channel modules; THX-approved; 20-year warranty.
Contact:
Bryston at 802-334-1201; www.bryston.ca.