Musical Fidelity B1xi Integrated Amplifier
The B-Line Celebrates its Return
Musical Fidelity High-End Philosophy Made Even More Affordable
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, Musical Fidelity invests 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 tradition
- Heavy front panel milled from extruded aluminium profiles
- Clean, stunning and indestructible metal exterior protects against electromagnetical interference
Key Features and Design Philosophy
The B1xi integrated amplifier channels Musical Fidelity's renowned amplifier expertise into a versatile, high-performance package. Driven by the design principles of their flagship models, the B1xi delivers 100W per channel into 4 ohms through a refined Class A/B circuit, offering a rich and dynamic 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.
Internal view highlighting key components:
- High-efficiency mains filter and standby-mode PSU
- MM phono preamp optimized for high gain and maximum clarity with lowest noise & distortion
- Low noise preamp design
- Low noise, generously rated toroidal transformer for clean and ample power reserves
- Isolated linear PSU for digital part
- Analogue motor-driven volume potentiometer
- Generously decoupled and fully regulated preamp PSU to eliminate supply rail variations and associated distortion
- Fully discrete Class A/B power amp driving power hungry speakers with ease and gracefully managing low impedance dips with filtered supply to signal stages
- Substantially rated power amp supply to provide lower overall noise and peaks into even difficult to drive speakers
Pure Class A/B Excellence
Transistor amps in Class A/B are best after tubes and Class A amps. Musical Fidelity aims for 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, capable of driving a wide range of speakers, even power-hungry models.
Internal view of the amplifier's power stage and toroidal transformer.
The preamp section features its own dedicated linear power supply, ensuring 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.
Vinyl lovers will appreciate the B1xi's exceptionally low-noise, high-gain phono stage, carefully tuned for musicality and detail, bringing out the best in MM cartridges without adding coloration or distortion.
Close-up view of internal circuitry, showcasing the preamp and phono stage components.
Separate Digital Boards and Robust Construction
Digital and analogue hardware are carefully separated to prevent RF interference. The B1xi utilizes a carefully trimmed DAC design using the ESS9018 chip. The digital coaxial, optical, and ARC inputs accept high-resolution sample rates up to 24bit/192kHz, allowing for enhanced home theatre experiences.
Internal layout showing separated digital and analogue boards, toroidal transformer, and power supplies.
The B1xi boasts an uncompromisingly heavy mechanical design with robust metal controls, an extruded aluminum front panel, and a chassis crafted entirely from metal, positioning it as a high-end amplifier for discerning audiophiles.
Front panel view of the Musical Fidelity B1xi Integrated Amplifier.
Musical Fidelity prioritizes sound quality and robust design. The B1xi features a high-quality isolated USB C 5V power output for modern streamers, effectively doubling as a power supply upgrade.
The Audiophile Truth
RF frequencies are managed through careful circuit layout and board placement to avoid interference with analog stages. The B1xi achieves exceptional price/performance for Musical Fidelity, combining carefully selected components, precisely tuned circuitry, and years of research and development to uphold the Musical Fidelity philosophy of making high-end audio affordable.
Rear panel view of the Musical Fidelity B1xi Integrated Amplifier, showing connectivity options.
Specifications
Amplifier
- Power, both channels driven @ 1% THD: 60 Watts per channel into 8 Ohms; 100W into 4 ohms; 140W peaks into 2 ohms
- Power, both channels driven @ 0.09% THD, 20Hz to 20 kHz: 50 Watts per channel into 8 Ohms; 80W into 4 ohms
- Voltage 21 Volts RMS, 20Hz to 20 kHz; onset of clipping
- 30 Volts peak to peak
- Current 8 Amps peak to peak
- Damping factor 30
- Output devices 1 pair per channel
Connections
- Line level inputs: 3 pairs line level RCA connectors
- MM phono input
- Optical, coaxial, ARC digital inputs (up to 24bit/192kHz stereo PCM)
- Bluetooth 5.1 input
- 1 pair line level RCA connectors, preamp outputs for e.g. bi-amping
- Speaker outputs: 1 pair 4mm banana plug/binding posts
Power requirement
- Mains voltages: 115/230VAC 50/60Hz (factory pre-set)
- 100VAC 50/60Hz (alternative)
- Consumption: 280 Watts maximum
Line input
- THD+N < 0.02% typical, 20Hz to 20 kHz
- Signal / noise ratio > 100dB 'A'-weighted
- Input impedance: 47k Ohms
- Frequency response +0, -3dB, 10Hz to 30 kHz
Phono input
- Sensitivity (nominal): 5mV (suitable for cartridges giving 1.5mV or more including high output MC types)
- Signal / noise ratio: >70dB 'A'-weighted
- Input impedance: 47k Ohms
- Input capacitance: <100pF
- Gain: 42dB
- Frequency response: RIAA/IEC ±1dB, 20Hz to 20 kHz
Weight
- Unit only, unboxed: 7.2 kg
- In shipping carton: 8.9 kg
Dimensions
- Wide: 430 mm
- High, including feet: 90 mm
- Deep (front to back) including terminals: 324 mm
