Musical Fidelity M6 500i Dual Mono Integrated Amplifier
In 1990, Musical Fidelity made the first ever Super Integrated amplifier: the A1000. This received a rapturous welcome and, even today, is selling at high prices second hand. The A1000 was the first of a long line of Super Integrateds from Musical Fidelity. The New Vista M3 , Tri Vista 300 and kW500, all were well received.
The M6 500i is the latest and the best of the breed.
The M6 500i is a separate preamp with two monobloc power amps sharing a common chassis. Each has its own heat sink and separate transformer. Genuinely dual mono.
The preamp has its own separate power supply winding.
The preamp input sockets are connected directly to the main preamp PCB. There are no wire connections from the inputs to the preamp. Consequently, PCB tracks are very short. This elegant idea ensures that both channels signals are ultra low impedance from the instant they get into the amplifier. This is a significant detail.
Each channel has twelve big bipolar transistors. 200 amps peak to peak is easily available.
The metalwork is high quality. The front panel is a custom made fine line extrusion of milspec aluminium. The custom made heat sinks have outstanding dissipation characteristic and finish.
The M6 500i construction has the feeling of solidity and quality.
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Technical Performance
The M6 500i delivers 500 + 500 wpc into 8 ohms. It is extremely stable and very linear.
The distortion is low too; about 0.008% @ 1 kHz and @ 20 kHz it is 0.015%. More significant, perhaps, is the very low distortion at ultra-high frequencies: @ 30 kHz, it is 0.02% and @ 50 kHz it is 0.02%.
The M6 500i has remarkable linearity and consistency. It is unconditionally stable and will drive any loudspeaker in existence easily with ample power reserve.
Our Approach To Technical Measurements
In our view an amplifier should be completely neutral. It is ‘a straight wire with gain’. Easy to say but hard and complex to do.
We want to stress that we do not believe that the technical performance is an end in itself. It is a method of validating the total amplifier system concept.
We believe that outstanding technical performance is the key to a neutral, faithful and musical sound. The aim of our circuit/PCB designs is to achieve complete neutrality and transparency. The proof that we are on the right track is the technical performance. We strongly disagree with the idea that inferior technical performance can ever be neutral or faithful.
We think that technical performance cannot be summed up by the distortion @ 1 kHz. Our view is that an amplifier has to be able to satisfy a wide range of technical requirements before it can be neutral.
Linearity
Almost all loudspeakers have complex impedance and loading curves. An amplifier must be able to maintain its voltage virtually, regardless of loading. If an amplifier cannot maintain its voltage across the spectrum, then the ultimate frequency response and distortion will be non 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 a fraction of the story. From our perspective, an amplifier must have very low distortion from 20 Hz – 20 kHz and beyond. We believe that an amplifier’s VHF performance proves the total performance of the circuit and PCB layout. The M6 500i’s distortion hardly changes from 10 kHz to 50 kHz. An outstanding achievement and validation of the circuit design and PCB layout.
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Noise Ratio
Amplifiers should be quiet. If they are not low level detail is irretrievably lost. Also, the dynamic range is seriously compromised. Dynamic range is not just how much power an amplifier will produce, it is also how quiet it can be. Dynamic range is the total from the quietest to the loudest. The M6 500i excels in this respect.
Precision Volume Control
The M6 500i has a precision digital volume control. This ensures perfect tracking right down to very low level. This outstanding precision is achieved by laser trimmed substrate resistors. When the M6 500i is switched off, it will remember the previous volume control setting. It will be the same for the next listening session.
Sound Quality
The M6 500i is effortless, fluid and dynamic. It doesn’t sound ‘loud’. It just sounds right. The dynamics are handled with no drama or fuss. They come and they go. There is no distortion; just pure undiluted music.
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Conclusion
We have tried our best to make the M6 500i as good as possible. It has huge reserve power, very low distortion, excellent linearity, good build quality and aesthetics.
