Musical Fidelity M8xi Stereo Integrated Amplifier DAC Silver

In 1990, Musical Fidelity released the first ever Super Integrated amplifier, the A1000. It was met with enthusiastic reception and still fetches a premium second hand today. The A1000 was the first in a long line of Musical Fidelity Super Integrated amplifiers. Its offspring, the NuVista M3, Tri Vista 300, kW500, M6/500i, NuVista 800 and NuVista 600 were all equally enthusiastically received by the audiophile world. The M8xi is the latest and greatest of the breed.

General Description

The M8xi is a separate pre-amplifier with two monoblock power amplifiers sharing a common chassis. Each has its own heat sink and separate transformer. Genuinely dual mono. The pre-amplifier has its own separate power supply and is mounted close to the input sockets. As a result, the PCB traces are very short. This elegant idea ensures that the signals from both channels are very low impedance the instant they enter the amplifier. This is a significant detail. Each channel has twelve large bipolar transistors: 200 amps peak-to-peak are readily available. The metalwork is of high quality. The front panel is a custom fine line extrusion of milspec aluminum. The custom heat sinks have exceptional dissipation characteristics and finish. The construction of the M8xi has a solid, quality feel.

New Circuit

Over the past 5 years our power amplifier circuitry has reached a high level of development. In our never-ending quest to improve performance and customer value, we have looked for ways to improve our designs. One of the main directives was to keep the low feedback configuration unchanged... keep the low feedback! The question was how to improve efficiency and performance without compromising sound quality. If I do say so myself, I think we have hit upon a brilliant solution. Our new M8xi power amplifier design delivers more power, less distortion and improved sound quality. Amazing but true. The efficiency of the output stage has been increased, producing approximately 10% more power for a similar supply voltage. More importantly, the entire driver stage is pure Class A. We believe this innovative approach has a substantial effect on sound quality. The soundstage appears wider while the micro and macro dynamics have more impact. This effect is particularly noticeable on a well-recorded piano. I am sure you all know that the piano is a percussion instrument, but in truth, this is rarely audible on most Hi-Fi systems. Using an M8xi the percussive nature of a piano becomes immediately obvious and jumps out of the speaker. It is a surprising and satisfying improvement in sound quality. Voices 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. It mostly sounds like a small Class A amplifier with a huge amount of power.

The DAC

The M8xi also features a 5-input DAC. DACs are increasingly common in integrated amplifier designs to add convenience when connecting a variety of digital sources, so the decision was made to integrate a DAC that would operate at a high level, independent of the amplifier. For added integrity, the DAC features its own power supply. Based on the low-distortion, low-noise PCM5242 DAC chip from Texas Instruments TI, which is also used in many other premium hi-fi products and previous Musical Fidelity products, the M8xi has 2 coaxial (S/PDIF), 2 optical (S/PDIF) and 1 asynchronous USB Type-B input. The coaxial and USB inputs are capable of supporting high-resolution audio streams up to 24-bit/192kHz and the optical input is capable of supporting up to 24-bit/96kHz. To achieve maximum performance, all data streams are upsampled and re-clocked by an internal converter to reduce jitter and remove unwanted artifacts in the sound.

Technical Performance

The M8xi delivers 550 + 550wpc into 8 ohms. It is extremely stable and very linear. Distortion is also low; less than 0.005% in the audible frequency range of 20Hz to 20kHz. The M8xi has remarkable linearity and coherence. It is unconditionally stable and will easily drive any existing loudspeaker with plenty of power in reserve.

Our Approach to Technical Measurements

In our opinion, an amplifier should be completely neutral. It's "a straight wire with gain". Easy to say, but difficult and complex to do. We want to emphasize that we do not believe that technical performance is an end in itself. It is a method to validate the concept of a total amplifier system. The goal of our circuit/PCB designs is to have low feedback and achieve complete neutrality, transparency and great technical performance. The proof that we are on the right track is the technical performance. We believe that technical performance cannot be summarized by distortion at 1 kHz. Our view is that an amplifier must be able to satisfy a wide range of technical requirements before it can be neutral.

Linearity

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

Distortion

The vast majority of amplifier manufacturers only talk about distortion at 1 kHz. We believe this is only a fraction of the story. In our view, an amplifier should have very low distortion from 20 Hz to 20 kHz and beyond. We believe that the high frequency performance of an amplifier demonstrates the total performance of the circuit and PCB layout. The M8xi distortion barely changes from 10 kHz to 50 kHz. An outstanding result and a validation of the circuit design and PCB layout.

Noise Ratio

Amplifiers should be quiet. If they are not, low-level detail is irretrievably lost. Additionally, dynamic range is seriously compromised. Dynamic range is not just how much power an amplifier will produce, but also how quiet it can be. Dynamic range is the total from the quietest to the loudest. The M8xi excels in this regard.

Precision Volume Control

The M8xi has a precision volume control. This ensures perfect tracking down to very low levels, something unattainable with standard potentiometers. This extraordinary precision is achieved via laser-cut substrate resistors.

Sound Quality

The M8xi is smooth, dynamic and effortless. It doesn't sound "loud". It just sounds right. Dynamics are handled without drama or fuss. They come and go. There is no distortion; just pure, undiluted music. It sounds like a superb little Class A amplifier but with unlimited headroom. Perfection!

FEATURES

Power Output (20Hz - 20kHz): 550 Watts per channel into 8 Ohms (870W into 4 Ohms); Peak 1.6kW into 2 Ohms

Maximum Output Voltage: 67 Volts RMS, 20Hz to 20kHz; beginning of clipping (190 Volts peak-to-peak)

THD+N: <0.004% typical, 20Hz to 20kHz (XLR)

Signal-to-Noise Ratio: > 86dB 'A' weighted (XLR)

Input impedance: 25KΩ (RCA), 50KΩ (XLR)

Frequency response: +0, -1dB, 10Hz to 100kHz

Maximum peak output current: 105 Amps

Damping factor: 150

Output devices: 3+3 pairs (bridged arrangement) per channel

Inputs (analog)

4 pairs of line-level RCA connectors

2 pairs of line-level XLR connectors (balanced)

Inputs (digital)

2x Coax S/PDIF up to 24-bit 192kHz

2x S/PDIF optical up to 24 bit 96kHz

1x USB B USB asynchronous up to 24 bit 192kHz

Outputs (analogue)

1 pair fixed RCA line level

1 pair variable RCA pre-outs

1 pair variable XLR line level

Outputs (digital)

1x Coax S/PDIF up to 24 bit 192kHz

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

General

Dimensions (WxHxDxD): 440 x 162 x 400mm

Max. Power Consumption: 2000Watts