Musical Fidelity M8xi

Description

The M8xi from Musical Fidelity is a powerful 2-channel amplifier that impresses with its innovative technology and outstanding features. With an impressive output power of 550 watts per channel at 8 ohms, it offers sufficient reserves to support any music performance with excellent sound quality. The amplifier has a dual-mono design, in which the preamplifier and power amplifier are each equipped with separate transformers and heat sinks. An integrated DAC with five inputs provides flexibility when connecting digital sources. Precise volume control and minimal distortion contribute to a clear and dynamic sound experience. Thanks to its well-balanced technology, the M8xi offers a reliable and high-quality listening experience for demanding music lovers.

Technical data

Amplifier

• Output power (20 Hz - 20 kHz): 550 watts per channel into 8 ohms (870 W into 4 ohms); peak value 1.6 kW into 2 ohms
  
• Maximum output voltage: 67 volts RMS, 20 Hz to 20 kHz; start of limiting (190 volts peak-to-peak)
• THD+N: <0,004 % typisch, 20 Hz bis 20 kHz (XLR)
• Signal-to-noise ratio: > 86 dB, A-weighted (XLR)
  
• Input impedance: 25 KΩ (RCA), 50 KΩ (XLR)
• Frequency response: +0, -1 dB, 10 Hz to 100 kHz
• Maximum peak output current: 105 A
• Attenuation factor: 150
• Output devices: 3+3 pairs (bridge arrangement) per channel

Inputs (analog)

• 4 pairs of line-level cinch connections
• 2 pairs of line-level XLR connections (balanced)

Inputs (digital)

• 2x coaxial S/PDIF up to 24 bit 192 kHz
• 2x optical S/PDIF up to 24 bit 96 kHz
• 1x USB B Asynchronous USB up to 24 bit 192 kHz

Outputs (analog)

• 1 pair of line-level cinch connections fixed
  
• 1 pair of preamplifier output RCA variable
• 1 pair Line level XLR variable

Outputs (digital)

• 1x coaxial S/PDIF up to 24 bit 192 kHz
• 1x optical S/PDIF up to 24 bit 96 kHz

General

• Dimensions (WxHxD): 485 x 185 x 510 mm
• Max. Consumption: 2000 Watt

M8xi - Overview

In 1990, Musical Fidelity launched the first super integrated amplifier on the market: the A1000. It was enthusiastically received and still fetches high prices on the second-hand market today. The A1000 was the first in a long line of super integrated amplifiers from Musical Fidelity. Its children: NuVista M3, Tri Vista 300, kW500, M6/500i, NuVista 800 and NuVista 600 were equally enthusiastically received by the audiophile world. The M8xi is the latest and greatest of its kind.

General description

The M8xi is a separate preamplifier with two monoblock power amplifiers that share a common chassis. Each has its own heat sink and a separate transformer. True dual-mono design. The preamplifier has its own separate power supply and is mounted close to the input sockets. As a result, the conductor paths are very short. This elegant idea ensures that the signals from both channels have an extremely low impedance as soon as they enter the amplifier. This is an important detail. Each channel has twelve large bipolar transistors that can easily deliver 200 amps peak-to-peak. The metalwork is of high quality. The front panel is a custom fine line extrusion of Milspec aluminum. The custom heat sinks have excellent heat dissipation properties and excellent workmanship. The M8xi construction conveys a sense of solidity and quality.

New circuits

Over the last five years, our power amplifier circuitry has reached a high level of development. In our relentless pursuit to improve performance and customer value, we have looked for ways to improve our designs. One of the key requirements was to leave the low feedback configuration unchanged... keep it low feedback! The problem was to improve efficiency and performance without compromising sound quality. I think we found a brilliant solution. Our new M8xi amplifier design offers higher power, lower distortion and better sound quality. Incredible, but true. The efficiency of the output stage has been increased, delivering around 10% more power for a similar supply voltage. More importantly, the entire driver stage operates in pure Class A. We believe this innovative approach has a significant impact on sound quality. The soundstage appears wider, while the micro- and macrodynamics have more impact. This effect is particularly noticeable with well-recorded piano pieces. I'm sure you all know that the piano is a percussive instrument, but in truth this is rarely audible in most hi-fi systems. When using an M8xi, the percussive nature of a piano is immediately apparent and jumps out of the speaker. It's a surprising and satisfying improvement in sound quality. Vocals have more subtlety, detail and presence. Large scale music has depth, breadth and an incredibly dynamic presentation. All in all, the M8xi is a consummate all-rounder. Most of the time it sounds like a small Class A amplifier with enormous power.

The DAC

The M8xi also features a 5-way input DAC. DACs are increasingly being used in integrated amplifier designs to facilitate the connection of a variety of digital sources. It was therefore decided to incorporate a DAC that delivers high performance independent of the amplifier. For added integrity, the DAC has its own power supply. The M8xi is based on the low distortion, low noise Texas Instruments PCM5242 TI DAC chip, which is also used in many other premium hi-fi products as well as previous Musical Fidelity products, and features 2 x coaxial (S/PDIF), 2 x optical (S/PDIF) and 1 x asynchronous USB Type B inputs. The coaxial and USB inputs support high-resolution audio streams with up to 24 bit/192 kHz, the optical input supports up to 24 bit/96 kHz. For maximum performance, all data streams are up-converted and re-clocked by an internal converter to reduce jitter and eliminate unwanted artifacts in the sound.

Technical performance

The M8xi delivers 550 + 550 Wp into 8 ohms. It is extremely stable and very linear. The distortion is also low; less than 0.005% in the audible frequency range from 20 Hz to 20 kHz. The M8xi has remarkable linearity and consistency. It is unconditionally stable and can easily drive any existing loudspeaker with sufficient power reserve.

Our approach to technical measurements

In our opinion, an amplifier should be completely neutral. It is "a straight wire with amplification". This is easy to say, but difficult and complex to implement. We would like to emphasize that we do not believe that technical performance is an end in itself. It is a method to validate the whole amplifier system concept. The goal of our circuit/PCB designs is to achieve low feedback and achieve complete neutrality, transparency and excellent technical performance. The proof that we are on the right track is the technical performance. We believe that technical performance cannot be summarized by the distortion at 1 kHz. In our view, an amplifier must be able to fulfill a variety of technical requirements before it can be neutral.

Linearity

Almost all loudspeakers have complex impedance and load curves. An amplifier must be able to nearly maintain its voltage regardless of the load. If an amplifier cannot maintain its voltage across the entire spectrum, the final frequency response and distortion will not be linear. This is not neutrality.

Distortion

The overwhelming majority of amplifier manufacturers only talk about distortion at 1 kHz. We believe that this is only part of the truth. In our view, an amplifier must have very low distortion from 20 Hz to 20 kHz and beyond. We believe that the high frequency performance of an amplifier proves the overall performance of the circuit and PCB layout. The distortion of the M8xi hardly changes from 10 kHz to 50 kHz. An outstanding performance and confirmation of the circuit design and PCB layout.

Noise ratio

Amplifiers should be quiet. If they are not, quiet details will be irretrievably lost. In addition, the dynamic range is seriously affected. The dynamic range not only indicates how much power an amplifier produces, but also how quiet it can be. The dynamic range is the sum from the quietest to the loudest. The M8xi excels in this respect.

Precise volume control

The M8xi has a precise volume control. This ensures perfect sound tracking down to very low levels, which is not possible with standard potentiometers. This outstanding precision is achieved by laser-trimmed substrate resistors.

Sound quality

The M8xi is effortless, fluid and dynamic. It doesn't sound "loud". It just sounds right. The dynamics are handled without drama or fuss. It comes and goes. There is no distortion, just pure, unadulterated music. It sounds like an excellent small class A amplifier, but with limitless headroom. Perfection!