Musical Fidelity B1xi stereo amplifier

The B1xi integrated amplifier channels Musical Fidelity's renowned amplifier expertise into a versatile and powerful package. Following the design principles of our flagship models, the B1xi delivers 100W per channel into 4 ohms through sophisticated Class A/B circuitry, delivering rich and dynamic tube-like sound.

Designed for today's diverse listening needs, the amplifier offers a comprehensive range of inputs: MM turntable, coaxial and optical digital inputs, HDMI ARC, Bluetooth and three RCA line inputs – all designed for seamless integration of audio sources. An adjustable RCA pre-out supports subwoofer connection or bi-amping, while a 5V USB-C output provides convenient and clean, high-quality power for an external streaming device. With a durable all-metal construction, solid metal controls and a sturdy aluminum front panel, the B1xi offers Musical Fidelity's renowned sound quality and build quality, providing a pure and uncompromising audio experience for discerning music lovers.

Pure Class A/B excellence with true high-end audiophile design

Class A/B transistor amplifiers are at their best after tubes and class A amplifiers. Musical Fidelity is tube-like sound and power. The B1xi delivers 60 watts per channel into 8 ohms, 100 watts into 4 ohms and 140 watts peak into 2 ohms. The amplifier will have no trouble driving a wide range of speakers, even high-power models.

Discrete power supply and toroidal transformer

A fully discrete Class A/B power amplifier, complemented by its separate power supply and generously sized toroidal transformer, ensures sufficient peak power and a wide dynamic range. Driving power-hungry and difficult speakers is easy. Low impedance drops are smoothly managed, and the thoughtfully sized output devices do not stall under any load.

Low-noise preamplifier and turntable stage

The preamp section has its own dedicated linear power supply – a rarity in integrated models. This separation ensures very low noise and excellent channel separation that rivals high-end preamp/power amplifiers. Volume control is via a motorized analog potentiometer, preserving signal purity – unlike many modern digital volume controls that compromise accuracy due to loss of signal resolution. Vinyl enthusiasts will appreciate the B1xi’s exceptionally low-noise, high-gain turntable stage. Carefully tuned for musicality and detail, it brings out the characteristics of your MM speaker without added coloration or increased distortion.

Separate digital circuit boards

The digital and analog sections must be carefully separated. Even the slightest RF interference is known to cause problems for analog amplifier stages. That is why the digital and ARC boards are physically separated on their own circuit boards and have their own linear power supply.

Drawing on our decades of experience in DAC design (most recently with the groundbreaking Nu-Vista DAC and M8x DAC), the B1xi features a carefully refined DAC utilizing the excellent ESS9018 chip. Digital coaxial and optical inputs accept up to 24-bit and 192kHz sampling rates, and with HDMI ARC input, the B1xi's powerful analog amplifiers bring your home theater to life and really spice it up.

Uncompromising mechanical design

With high-end elements such as durable metal controls, an extruded aluminum front panel, and an all-metal chassis, the B1xi is an enviable choice for discerning audiophiles looking for a pure high-end amplifier.

Intentionally without WiFi

The B1xi remains committed to sound quality over WiFi, display and app. It NO We have seen a proliferation of HiFi companies offering all-in-one solutions, and unfortunately such developments have become expensive and difficult to maintain.

So manufacturers started saving money somewhere: Cheap plastic cases, cheap digital amplifiers, cheap power supplies. Musical Fidelity means sound quality and durable design that will last for decades. WE INVEST our money and resources in top-notch hardware and the pursuit of optimal music reproduction. This means: Durable mechanics - Discrete circuits - Huge transformers - Class A/B amplifiers. Rapidly evolving streaming technology is best kept separate, so it doesn't negatively impact the lifespan of the B1xi. That's why the B1xi features a high-quality isolated USB C 5V power output for your favorite modern streaming device - in effect, it also acts as a power supply upgrade for it.

The audiophile truth

All radio frequencies affect the performance of an analogue amplifier. That's why our design team, led by Technical Director Simon Quarry:

• spent a year improving the circuit layout and aligning the circuit boards with the transformer
• carefully selected components to ensure long-term availability and reliability, avoiding changes that would require product redesign
• RF shielding and PCB placement to avoid interference with analog amplifiers

The B1xi achieves unprecedented value for money at Musical Fidelity. Through carefully selected components, precisely tuned circuit layouts and years of research and development, the B1xi remains true to the Musical Fidelity philosophy and makes high-end products available at an unprecedented price.

B1xi in brief

Amplifier

• Fully discrete transistor-based class A/B power amplifier in keeping with Musical Fidelity's tradition
• Drives power-hungry speakers effortlessly
• Output power 60 W/8 ohms, 100 W/4 ohms and 140 W/2 ohms
• Power reserves to ensure sufficient peak power and wide dynamic range
• Pure sound quality instead of WiFi, screen and app
• No WiFi, no screen, no app on purpose: Instead, we invest in components that make a difference in sound quality

Preamplifier

• Low-noise design for best THD and signal integrity at both low and high levels
• High quality motor-driven analog potentiometer
• Preamp output for bi-amping or connecting an active subwoofer
• MM turntable connection

Digital

• Separate digital and ARC cards with their own linear power supply
• Up to 24-bit/192kHz stereo PCM: 1 x coaxial, 1 x optical, 1 x ARC input
• Bluetooth 5.1 input

Power supply

• Efficient toroidal transformer
• Separate power supplies for preamplifier, power amplifier and digital section
• The output stages and power supply are sized well enough to provide peak power even for difficult-to-drive speakers.
• 5V USB-C power supply for powering many new external streaming devices

Mechanical structure

• Uncompromising metalwork in the typical Musical Fidelity tradition
• The thick front panel is milled from extruded aluminum profiles
• Clean, sleek and durable metal exterior protects against electromagnetic radiation

SPECIFICATIONS:

Amplifier

• Power, both channels driven at 1% THD: 60 watts per channel into 8 ohms; 100 watts into 4 ohms; 140 watts peak into 2 ohms
• Power, both channels driven at 0.09% THD, 20 Hz to 20 kHz: 50 watts per channel into 8 ohms; 80 W into 4 ohms
• Voltage 21 volts RMS, 20 Hz - 20 kHz; cutting begins
• 30 volts peak to peak
• Current 8 amps peak to peak
• Damping factor 30
• Output devices 1 pair per channel

Line input

• THD+N < 0.02% typical, 20 Hz - 20 kHz
• Signal-to-noise ratio > 100 dB 'A'-weighted
• Input impedance 47 kohm
• Frequency response +0, –3 dB, 10 Hz - 30 kHz

Phono input

• Sensitivity (nominal): 5 mV (suitable for cartridges that output 1.5 mV or more, including high output MC cartridges)
• Signal-to-noise ratio: >70 dB 'A'-weighted
• Input impedance: 47 kohm
• Input capacitance: <100 pF
• Gain: 42 dB
• Frequency response: RIAA/IEC ±1 dB, 20 Hz - 20 kHz

Connections

• Line level inputs: 3 pairs RCA
• MM turntable input
• Optical, coaxial, ARC digital inputs (up to 24-bit/192 kHz stereo PCM)
• Bluetooth 5.1 input
• 1 pair of line-level RCA, preamp outputs for e.g. bi-amping use
• Speaker outputs 1 pair of 4mm banana plugs/pins

Power requirements

• Mains voltage 115/230 VAC 50/60 Hz (factory setting)
• 100 VAC 50/60 Hz (optional)
• Consumption up to 280 watts

Weight

• Device only 7.2 kg
• In shipping box 8.9 kg

Dimensions

• Width 430 mm
• Height xxx mm, including legs 90mm
• Depth (front to back) including connectors 324 mm