B1xi - Overview

The B1xi integrated amplifier channels Musical Fidelity’s renowned amplifier expertise into a versatile, high-performance package. Driven by the design principles of our flagship models, the B1xi delivers 100W per channel into 4 ohms through a refined Class A/B circuit, offering a rich and dynamic tube like sound.

Designed for today’s diverse listening needs, it features a comprehensive input selection: MM phono stage, coaxial and optical digital inputs, ARC, Bluetooth, and three RCA line inputs—all engineered for seamless source integration. A variable 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 streamer. Encased in robust all-metal construction with solid metal controls and a solid aluminum front panel, the B1xi offers the sonic and build quality Musical Fidelity is known for, delivering a pure, uncompromised audio experience for discerning music lovers.

Pure Class A/B Excellence with True High-End Audiophile Design

Transistor amps in Class A/B are best after tubes and Class A amps. Musical Fidelity is tube like sound and power. The B1xi delivers 60 watts per channel into 8 ohms, 100 watts into 4 ohms and 140W peaks into 2 ohms. It won’t struggle to drive a wide range of speakers, even power-hungry models.

Discrete power and toroidal transformer

The fully discrete Class A/B power amp, complemented by its dedicated power supply and generously proportioned toroidal transformer, guarantees reserves for proper peak delivery and a wide dynamic range. Power hungry and difficult speakers are driven with ease. Low impedance dips are managed gracefully and the judiciously rated output devices won‘t faulter under any load.

Low noise preamp and phono stage

The preamp section features its own dedicated linear power supply—a rarity in integrated designs. This separation ensures ultra-low noise and excellent channel separation, rivaling high-end pre/power separates. Volume control is handled via a motor-driven analogue potentiometer, preserving signal purity—unlike many modern digital volume controls that compromise fidelity due to a loss in signal resolution. Vinyl lovers will appreciate the B1xi’s exceptionally low-noise, high-gain phono stage. Carefully tuned for musicality and detail, it brings out the best in your MM cartridges without adding coloration or distortion.

Separate digital boards

Digital and analogue hardware needs to be carefully separated from each other. Even the smallest amount of RF interference is known to cause trouble for analogue amplifier stages. Therefore, the digital and ARC boards are physically separated on their own PCBs and have their own linear power supply.

Drawing from our decade long experience in designing DACs (recently with our ground-breaking Nu-Vista DAC and M8x DAC), the B1xi uses a carefully trimmed DAC design using the superb ESS9018 chip. The digital coaxial and optical inputs accept high-resolution sample rates up to 24bit and 192kHz and the HDMI ARC input allows your home theatre to be brought to life and properly invigorated by the powerful B1xi analogue amp stages.

Uncompromisingly heavy mechanical design

The inclusion of high-end elements such as the robust metal controls, extruded aluminium front panel, and a chassis crafted entirely from metal, the B1xi occupies an enviable position for discerning audiophiles seeking an unadulterated high-end amplifier.

No WiFi on Purpose

The B1xi remains committed to sound quality instead of WiFi, a display and an App. There is NO WiFi streaming on purpose. We’ve seen a surge in offerings from HiFi companies with all-in-one solutions and unfortunately, such developments are HUGLY EXPENSIVE and on top very maintenance heavy.

Consequently, manufactures started to save the money somewhere: Cheap plastic cabinets, low-cost digital amplifiers, low-cost power supplies. Musical Fidelity stands for sound quality and robust design that lasts for decades. We INVEST our money and resources in top-tier hardware and the pursuit of optimal music reproduction. This means: Robust mechanics - Discrete circuits - Huge transformers - Class A/B amps. Fast moving streaming technology is best kept separate and therefore will not negatively impact the lifecycle of the B1xi. For that reason, the B1xi features a high-quality isolated USB C 5V power output for your favorite modern streamer – effectively also doubling as a power supply upgrade for it.

The Audiophile Truth

Any RF frequencies are influencing the performance of the analogue amplifier. Consequently, our design team, headed by chief technical director Simon Quarry:

• took one year to improve the layout of the circuitry and match the boards in relation to the transformer
• carefully selected components for long-term availability and reliability, to avoid any change which would cause a redesign of the product
• RF shielding and board placement to avoid interference with analog stages



The B1xi achieves price/performance like never before for Musical Fidelity. With carefully selected components, precisely tuned circuitry layout and years and years of research and development the B1xi stays true to the Musical Fidelity philosophy and makes high-end affordable like never before.



The B1xi In Brief

Amplifier

• Fully discrete transistor based Class A/B power amp design in Musical Fidelity tradition
• Drives power hungry speakers with ease
• 60W/8 Ohm, 100W/4 Ohm & 140W/2 Ohm output power
• Power reserves for proper peak power delivery and wide dynamic range
• Pure sound quality instead of WiFi, display and App
• No WiFi, display and App on purpose: Instead, we invest in components, which decide the sound quality



Preamplifier

• Low noise design for best THD and signal integrity at low as well as high levels
• High quality motor-driven analogue potentiometer
• Pre out for bi-amping or active subwoofer connection
• MM phono stage



Digital

• Separate digital and ARC boards with own linear PSU
• Up to 24bit/192kHz Stereo PCM: 1x Coaxial, 1x optical, 1x ARC inputs
• Bluetooth 5.1 input



Power Supply

• Generously rated toroidal transformer
• Independent power supplies for preamp, poweramp and digital part
• Output devices, and power supply generously rated to provide peaks even into difficult to drive speakers
• 5V USB C power output to power many new modern external streamers



Mechanical Construction

• Uncompromising metal work in typical Musical Fidelity tradtion
• Heavy front panel milled from extruded aluminium profiles
• Clean, stunning and indestructable metal exterior protects against electromagnetical