Bryston 4B SST Power Amplifier — 300 WPC, Dual Mono, XLR, Canada

Bryston 4B SST Dual Mono Power Amplifier — 300 Watts Per Channel, Balanced and Single-Ended Inputs, Built in Peterborough, Ontario

The 4B is the amplifier Bryston has been building and refining since 1978, and it is the one that made the company’s name. Recording studios bought it because it did not fail. Touring companies bought it because it did not fail after being thrown in the back of a truck. Audiophiles came to it afterwards, and stayed, because an amplifier built to survive a road case turns out to be a very good thing to have at home.

True Dual Mono

This is the SST generation, and it is a true dual-mono design. Not two channels sharing a power supply with a partition between them — two complete amplifiers in one chassis, each with its own toroidal transformer and its own filter capacitor bank, sharing only the power cord. Whatever one channel is asked to do has no effect on what the other one can deliver.

The Power

Three hundred watts per channel into 8 ohms. Five hundred per channel into 4 ohms. Bridged to mono it will produce in the region of 900 watts into 8 ohms. These are Bryston’s own figures and Bryston’s figures have a long-standing reputation for being conservative — independent measurements of this family have consistently come in above the published numbers rather than below them.

The Specifications That Matter

The specifications behind those watts are what matter more. Distortion below 0.005% from 20Hz to 20kHz at full rated output. A damping factor over 500 at 20Hz, which is the number that describes how completely the amplifier controls a woofer — at that figure the driver stops when the signal stops, and bass arrives as pitch rather than as weight. Slew rate over 60 volts per microsecond. Power bandwidth from under 1Hz to beyond 100kHz.

Balanced and Single-Ended Inputs

Both balanced XLR and single-ended RCA inputs are fitted, with a switchable gain setting of 29dB or 23dB so the amplifier can be matched properly to whatever preamplifier is in front of it rather than leaving you to solve a level mismatch with the volume control.

Built in Peterborough

It is built in Peterborough, Ontario, and it has been built there continuously for close to fifty years. That is not a marketing line about heritage — it is why parts and service for these amplifiers remain available in this country when a great deal of equipment of the same age has been orphaned by its manufacturer.

Size and Weight

It measures 19 inches across the front, 5.25 inches tall and 17.25 inches deep, and weighs 50 lbs. Allow for depth: 17.25 inches of chassis plus speaker cable and interconnects behind it wants a shelf around 20 inches deep, or a rack.

Condition

Condition is excellent.

Who This Suits

For anyone driving a demanding pair of speakers — a low-impedance load, a big room, or a panel that has humbled lesser amplifiers — this is one of the few power amplifiers with a genuine reputation for simply never being the problem. Available for pickup in Kanata. Because of its weight, this piece does not travel by standard courier — see the shipping note below; we arrange personal delivery or skid-mounted freight, and every piece is packed in-house in 275 lb test double-wall boxes.

Bryston 4B SST Dual Mono Power Amplifier Specifications

• Configuration: dual mono, two channels
• Power output: 300 watts per channel into 8 ohms
• Power output: 500 watts per channel into 4 ohms
• Bridged mono: approximately 900 watts into 8 ohms
• THD + noise: under 0.005%, 20Hz to 20kHz at rated output into 8 ohms
• Damping factor: over 500 at 20Hz, referenced to 8 ohms
• Slew rate: over 60 volts per microsecond
• Power bandwidth: under 1Hz to over 100kHz
• Inputs: balanced XLR and single-ended RCA
• Input impedance: 50k ohms single-ended, 20k ohms balanced
• Gain: switchable, 29dB or 23dB
• Outputs: five-way binding posts
• Power supply: two toroidal transformers, one per channel
• Built in: Peterborough, Ontario, Canada
• Dimensions: 19″ W x 5.25″ H x 17.25″ D (483 x 133 x 438 mm)
• Weight: 50 lbs (22 kg)
• Condition: Excellent

⚠️ Important Information for International Buyers

This unit is configured for North American 110/120V power. Buyers outside North America will require a step-down transformer and appropriate plug adapter.

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Backed by Radique Audio’s Bumper-to-Bumper Warranty and our Perpetual Trade-Back Program. When you’re ready to move on, we’ll take it back. That’s the Radique difference.

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