Bryston 4B³ Stereo Power Amplifier - Silver, 17 Inch
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Bryston 4B³ Stereo Power Amplifier - Silver, 17 Inch
The One Most People Should Buy
Bryston has built a version of the 4B since 1976, and the Cubed generation is the one to own. It makes 300 watts per channel into 8 ohms and 500 into 4, which is enough for nearly any speaker in nearly any room, without stepping up to the size and cost of a flagship.
Each channel runs its own power supply and its own transformer. Nothing is shared but the power cord. So a bass note that leans hard on one channel cannot rob the other, and the stereo image holds together when the volume goes up rather than collapsing toward the middle.
And it has a second life if you need one. A pair of 4B³s can be bridged to mono, 900 watts each into 8 ohms, so the amplifier you buy today can become half of a monoblock pair later rather than being traded in.
Quiet by Design, Not by Accident
All Cubed amplifiers use a patented input circuit developed with Dr. Alexandru Salomie. It takes the first stage of gain and is built to reject the interference a modern house is full of, from Wi-Fi to switching power supplies.
The result is a background that stays out of the way: noise measures −112dB through RCA and −117dB through the balanced XLR input. THD+N holds at or below 0.005% from 20Hz to 20kHz at the full 300 watts, and response runs from below 1Hz to 100kHz at −3dB.
Every 4B³ is burned in at the factory for 100 hours and comes with a printout of its own measurements, so you see how your unit performed rather than a brochure figure. It weighs 42 pounds, is convection cooled with no fan, and Bryston builds it in Dwight, Ontario, with a 10-year warranty.
What Reviewers Are Saying
Roger Kanno reviewed the 4B³ for SoundStage! Hi-Fi. "With virtually faultless sound and the ability to drive just about any speaker with ease, the 4B3 may well be the best value today in a high-end, high-powered, solid-state amplifier," he wrote.
What he heard was "sound that was at once brawny and precise, yet very subtle and refined when the music required it." His bottom line: "If I were in the market for a new amp, I'd buy the Bryston 4B3 without hesitation."
Christiaan Punter of HiFi-Advice, reviewing the Cubed range on 26 December 2017, found the treble "supremely subtle and decidedly non-edgy, even with the most critical speakers", and the series as a whole "generous, smooth, rich and relaxed, yet very powerful".
Who Is This Amplifier Best For?
- You want to stop thinking about power — 300 watts into 8 ohms and 500 into 4 covers almost any speaker in almost any room, so the amplifier stops being the part of the system you worry about.
- Your system might grow — a second 4B³ bridges the pair to 900 watts of mono each, so today's stereo amp becomes half a monoblock rig later instead of a trade-in.
- You want proof, not promises — every unit is burned in for 100 hours and ships with a printout of its own bench measurements, so you know what yours actually does.
- You buy once — ten years of warranty on an amplifier built in Dwight, Ontario, and cooled by convection alone, so there is no fan to fail and nothing to service on a schedule.
- You do not own a preamplifier yet — the 4B³ is a power amplifier, with no volume control and no input switching. Choose a partner from our preamplifiers and the two together make a complete system.
How Does It Connect to Your System?
Feed it from your preamplifier by balanced XLR or single-ended RCA, selecting the input on the rear panel. Input impedance is 7.5k ohms unbalanced and 30k ohms balanced. Speakers go to the binding posts, which take spades, bananas or bare wire.
Set gain to 23dB or 29dB so your volume control sits in a comfortable range. A DC trigger brings the amp up with the rest of the system, and a controlled startup sequence stops it tripping a breaker on switch-on.
Pairs Well With
Building around the 4B³? Here are some great companions:
- Preamplifier: Required, and the natural next decision — see our Preamplifiers.
- Speaker Cables: Five hundred watts into 4 ohms needs cable to match — see our Speaker Cables.
- Interconnects: Balanced XLR is the better run from preamp to amp — see our Interconnect Cables.
- Audio Rack: Forty-two convection-cooled pounds wants air around it — see our Audio Racks.
Frequently Asked Questions
How much power does it make?
300 watts per channel into 8 ohms and 500 watts per channel into 4 ohms. Bridged to mono, a 4B³ makes 900 watts into 8 ohms.
How is it different from the 3B³ and the 14B³?
Power, mostly. The 3B³ makes 200 watts per channel, the 4B³ 300, and the 14B³ 600. All three share the same Salomie input circuit and dual-mono construction.
What do the two gain settings do?
They set how hard the amplifier amplifies, at 23dB or 29dB. Choose the one that puts your preamp's volume control in a usable range.
Can I rack-mount it?
The 17-inch and 19-inch faceplates on this listing are not rack-mountable, though the 19-inch does add front handles. Bryston makes a separate PRO version with a rack-mount panel — call us on 800-942-0220 and we will work out which one you want.
Does it come with test results?
Yes. Every Bryston amplifier is burned in for 100 hours and ships with a printout of its own measurements.
Where is it built, and what warranty does it carry?
Bryston builds it in Dwight, Ontario, Canada, and covers it with a 10-year warranty.
See It in Action
A first listen to the 4B³ in a working system:
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Learn More
Want to learn more about power amplifiers, bridging amplifiers to mono, or building a separates system? Visit our Learning Center for guides, tips, and expert advice.
4B³ Power Amplifier
- Two-channel power amplifier
- Power output: 300 watts per channel at 8 ohms; 500 watts at 4 ohms; bridged mono 900 watts per channel at 8 ohms
- Balanced XLR and TRS as well as singled ended RCA inputs are both available and can be selected using the Input Select switch on the rear panel of the amplifier
Cubed Series Features
- Patented circuitry developed in conjunction with Dr. Alexandru Salomie
- New patented input circuit is precisely optimized and linear
- Input circuit features 12 active devices in a groundbreaking array
- Quad-Complementary output mimics the characteristics of a Class-A design, but with dramatically lower distortion
- Each amplifier channel includes its own fully independent power supply with separate transformer
- Dramatically less distortion at the input stage
- Improved common mode noise rejection
- Major improvement in EMI/RFI noise rejection
- Less than 500mW standby power consumption
- Updated dress panel aesthetic with clean lines and new finish
- Cubed Series models are available in black or silver colored dress panels and are 17 or 19 inches wide; 19"-wide models include front mounted handles.
- Manufactured in Bryston's state-of-the-art Peterborough, Ontario Canada facility utilizing many locally sourced components
- Each product receives one hundred hours of burn-in before shipping and rigorous pass/fail testing plus achievement of performance benchmarks
- Amplifiers are warranted to be free of defects in materials and workmanship for a full twenty years
- Power output: 300 watts per channel at 8 ohms; 500 watts at 4 ohms; bridged mono 900 watts per channel at 8 ohms
- Gain: High 29 dB at 28.28 V/V; Low 23 dB at 14.14 V/V
- Sensitivity: High: 1.0V, 100W; High: 1.7V, 300W; Low: 2.0V, 100W; Low: 3.5V, 300W
- Input Impedance, Individual Mode: Single Ended ≈60k ohm; Balanced + ≈60k ohm; Balanced - ≈12.5k ohm;
- Input Impedance, Bridged Mode: Single Ended ≈10k ohm; Balanced + ≈10k ohm; Balanced - ≈10k ohm;
- IMD: ≤0.005%, Typ. ≤0.002%
- Noise (input shorted 20Hz to 20kHz): High: 29 dB, <0110dB (-75 dBu); Low: 23 dB, <0113dB (-78 dBu)
- Damping: 20 Hz, 8 Ohms, >500
- Power consumption (watts): Standby: <0.5; Idle: ≤70; 2Ch. 35W 8 ohm: 550; 2 Ch. 300W 8 ohm: 1000; Bridged: 900W 8 ohm: 1700
- Dimensions: 17" or 19" wide, 6.3" high, 16.2" deep (add 1.6" depth to C-Series 19"-wide model for front-mounted handles)
- Weight: 63 lbs.
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