Bryston 21B³ 3-Channel Power Amplifier

Bryston 21B³ 3-Channel Power Amplifier

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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.


  • Designed to meet the power requirements of a single active loudspeaker
  • Balanced and Single Ended audio inputs
  • No fans or other moving parts
  • Regulated power supplies to all voltage gain stages
  • Convection cooled and housed in a fully aluminum chassis
  • Independent power supplies for each channel
  • Energy storage power transformers maximize dynamic range

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Frequency Response
<1Hz to 100kHz (-3dB)
Total Harmonic Distortion Plus Noise <0.005%
Power Output (Per Channel) 8 Ohms (Channel 1)
Power Output (Per Channel) 8 Ohms (Channel 2/3) 300W
Power Output (Per Channel) 4 Ohms (Channel 1) 900W
Power Output (Per Channel) 4 Ohms (Channel 2/3) 500W
Noise - Unbalanced (RCA) <-115dB
Noise - Balanced (XLR) <-116dB
Input Impedance - Unbalanced (RCA) 7.5 kOhms
Input Impedance - Balanced (XLR) 5 kOhms / leg
Switchable Gain 23dB / 29dB
Standby Power Consumption <500MW
Dimensions WxHxD 17/19" x 8.1" x 16.8"
Dimenions (With Front Handles) WxHxD 17/19" x 8.1" x 18.4"
Weight 91lbs (41kg)