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21B SST³

The Bryston 21B³ three channel amplifier was crafted to provide superb amplification for your Bryston Active Loudspeaker System.


20 year warranty

Finance example

£2,400.00 initial 20% deposit then £320.00 per month for 30 months. Other finance terms available. Finance subject to status

21B SST³


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.

Inputs: 3x Balanced Inputs (XLR or TRS), 3x Single Ended Inputs (RCA)

Power Capabilities:

1x 600W into 8Ω

2x 300W into 8Ω

1x 900W into 4Ω

2x 500W into 4Ω


Designed to meet the power requirements of a single active loudspeaker

Balanced and Single Ended audio inputs

Selectable gain at 23 or 29dB

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

Tech spec

Harmonic Distortion (1st Channel):

≤.005% from 20Hz to 20kHz at 600W

Noise below full output (1st Channel):

-113dB single ended, -116dB balanced

Harmonic Distortion (2nd and 3rd Channel):

≤.005% from 20Hz to 20kHz at 300W

Noise below full output (2nd and 3rd Channel):

-110dB single ended, -113dB balanced

Slew Rate:


Power Bandwidth:

<1Hz to >100kHz

Damping Factor:

>300 at 20Hz (8Ω

For more information click here to visit the Bryston website


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