Bryston 28B³ Cubed Mono Amplifier

The top of the Cubed range

The Bryston 28B³ Cubed Mono Amplifier is the flagship monoblock in the Cubed series, delivering 1000W into 8Ω and 1800W into 4Ω from a quad complementary output stage. It is sold as a single unit, so a stereo system takes two. This is the amplifier Bryston builds when current delivery matters more than chassis count.

Why You'll Love It

• Effortless with any load. 1000W into 8Ω doubling to 1800W into 4Ω shows a power supply that holds its voltage under load, which is what keeps bass tight when the music gets busy.
• Grip on the drivers. A damping factor above 500 at 20Hz into 8Ω means the amplifier keeps firm control of large bass drivers rather than letting them overhang.
• Quiet in every sense. Convection cooling means no fan noise, and a signal to noise ratio of -117dB balanced leaves the background properly black between notes.

Under the Hood

• Quad complementary output topology paired with the patented Cubed input stage and Salomie circuit, cancelling distortion at the input rather than correcting it later.
• Balanced XLR (pin 2 positive) and unbalanced RCA inputs, 29dB gain, 3.16V sensitivity for full output, input impedance 5kΩ unbalanced and 5kΩ per leg balanced.
• Slew rate above 120V per microsecond, THD below 0.005% at rated power from 20Hz to 20kHz, with SoftStart turn-on and a 5V to 12V AC or DC trigger input.

CHT Insider Verdict

The 28B³ is aimed at large rooms and speakers that punish ordinary amplifiers. What you get for the money is not just volume, it is composure, the sense that nothing is being asked to work hard. It is heavy, it draws real power at idle, and you need two of them, so plan the rack and the power circuit before it arrives.

Pro Tip: These run warm even without a signal, so give each chassis breathing room above and to the sides. A closed cabinet with no ventilation is the fastest way to shorten the life of any big class AB amplifier.