21B Cubed 3 Channel Amplifier Pair - Open Box

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To some, their favorite Bryston amplifier is the 14B³. It features huge power, utterly silent noise floor, grace in an iron fist. The Bryston 14B³ has the kind of power usually only found in monoblocks, yet this model is a dual channel. That's not to say it is compact, however. This amplifier is big and heavy. Yet it drives any loudspeaker with agility and speed rendering your favorite music with exquisite detail.

Bryston impressed the audiophile community with an ultimate fully active loudspeaker system that let you choose your own amplifiers. Listeners were free to build 6-channel systems any way they liked. Now Bryston introduces the 21B³-an amplifier dedicated to bringing Cubed Series excellence to an easy to manage package. Each 21B³ has 3 channels. One is rated at 600 watts, the other two are rated at 300 watts each. Active loudspeaker customers will use the high powered channel for the bass section and smaller channels for the midrange and high frequency sections of their 3 way systems. Since the 21B³ is based on the 7B³ and 4B³ amps, it can also be used to power any 3 channels such as the front LCR in a home theatre.

The Bryston 21B³ three channel amplifier was crafted to provide superb amplification for your Bryston Active Loudspeaker System. The Bryston 21B³ is essentially composed of a 7B³ and a 4B³ amplifier, which provides plenty of power for a single active loudspeaker. Two of these amplifiers will drive your active system with breathtaking ease and clarity.

The Bryston 21B³ three channel amplifier was crafted to provide superb amplification for your Bryston Active Loudspeaker System. The Bryston 21B³ is essentially composed of a 7B³ and a 4B³ amplifier, which provides plenty of power for a single active loudspeaker. Two of these amplifiers will drive your active system with breathtaking ease and clarity.

Fully active loudspeaker systems dispense with passive crossovers found in conventional loudspeakers in favor of inserting the crossovers before the amplifier. The benefits include increased flexibility of filter shapes, the ability to make fine-grained adjustments resulting in improved on and off axis response (these are often competing objectives in passive loudspeakers), direct coupling of the amplifier to the driver (avoiding losses inherent in passive crossovers), and higher SLP with lower distortion. The Bryston Active Loudspeaker System combines decades of research into acoustics, electronics, amplification, and state of the art components to recreate your recordings with stunning realism.

First to Last Watt Philosphy

A significant part of the design criteria for the new Cubed series was to develop amplifiers that would maintain an ideal power curve from the first watt to the last. Most amplifiers exhibit a power curve where the best noise floor, drive capability and distortion are acheived from about 1/3 power and up. The new Bryston Cubed series amplifiers maintain their ideal power curve starting right from the first watt.

Achieving this starts with a number of design approaches:

1. Complete freedom from low-level crossover, zero-crossing, artifacts

   Most class-AB amplifierrs have sufficient bias to prevent primary crossover distortion, but secondary crossover distortion is caused by insufficient speed in the driver transistors. The Cubed Series uses very fast drivers to help prevent this, as well as proprietary technology. Bryston's Quad Complementary Output design vastly reduces the capacitance seen by the driver transistors, virtually eliminating storage delay in the output stage that could contribute to nonlinearities in the zero-crossing region.

2. Continuing efforts to reduce low-level noise. The clarity of level noise

   The clarity of Bryston's designs is enhanced at low listening levels by pushing the noise floor far below the signal level, improving the silence between the notes and enhancing the clarity of the music at low power levels.

3. Concentration on reducing distortion at all levels, especially high frequencies

   Bryston amplifiers are perhaps the only designs to concentrate so much effort at reducing HF distortion artifacts, and the results are remarkably flat THD-with-frequency curves, sho frequency curves, sho frequency curves, showing almost no tendency to wing almost no tendency to increase distortion as frequency rises. This has the effect of reducing overall haze, helping to pull the quietest passages out of the background.

Additionally, the new Cubed Series employs highly effective RF employs highly effective RF rejection in the power supplies, which traps and eliminates radio-frequency hash from either interfering with or emanating from the amplifier via the power cable or signal cables.

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Press and Reviews

Bryston Magazine

Guides & Advice
by Moon Audio

Soundstage

by Roger Kanno
Dec. 2018