M5

The Audio Note (UK) M5 Pre Amplifier has been specifically engineered for sonic performance rather than technical specification, and fulfills all Audio Note (UK) Level 3 criteria: -

 

Pure Class A operation

Zero negative feedback

Single Ended circuit topology

Valve rectification

Materials and component quality

 

It is well known that the accurate reproduction of music, not just sound, requires the purity of the incoming signal to be preserved. It is therefore not difficult to conclude that, in order to achieve this goal and to retain the musicality of the original performance, the complexity of the circuitry itself must be kept to a minimum. In response to this, the M5 Pre Amplifier uses a single-ended, zero feedback circuit topology. This is simply the most linear design possible, demanding pure Class A valve operation and removing the need for a phase splitter, which introduces unnecessary crossover distortion.

 

In contrast to the majority of the audio industry, we design our circuits with the aim of minimising non-harmonic and time-based anomalies, rather than producing vanishingly small harmonic or low intermodulation distortion measurements. These non-harmonic amplitude and time-based distortions have a highly perceptible and adverse affect on the signal waveform, and it is far more important to address these factors than participate in the increasingly irrelevant numbers game that chases "perfect measured response."

 

As a result, the M5 was designed for maximum linearity and minimum transient distortion, and avoids the need for detrimental "corrective" measures, such as inherently error-prone feedback loops.

 

Rather than using separate controls for volume and balance, the M5 Line is equipped with a dedicated Audio Note (UK) stepped attenuator for each channel. This not only brings the enormous improvements in sound quality expected from the now legendary Audio Note (UK) stepped attenuators, but also provides a level of channel balance accuracy that is impossible to achieve with conventional volume and balance potentiometers.

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The M5 Pre Amplifier features an ECC82 and 5687 line stage, and uses a 6X5 valve-rectified power supply based on the M10 Galahad PSU. This power supply also incorporates an ECL82 for voltage regulation and a 5651 as a voltage stabiliser. Audio Note (UK) Copper wiring, tantalum resistors, SILMIC filter capacitors and Audio Note (UK) copper foil signal capacitors are used throughout the circuit, along with in-house designed and manufactured, custom Audio Note (UK) output transformers which feature a HiB c-cores and copper windings. The M5 Line also has a correctly designed and implemented balanced output circuit.

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At the heart of the M5 RIAA is an exceptionally fine moving magnet phono stage which uses three 5670 valves. This is followed by a 5687 line stage, and both sections are powered by their own dedicated 6X5 valve rectified power supply based on the M10 Galahad PSU. These power supplies also incorporate an ECL82 for voltage regulation and an 5651 as a voltage stabiliser.  Audio Note (UK) Copper wiring and tantalum resistors, Audio Note (UK) copper foil signal capacitors and custom  Electrolytic capacitors are used throughout the circuit, along with in-house designed and manufactured, custom Audio Note (UK) output transformers which feature HiB double c-cores and copper windings. The M5 RIAA also has a correctly designed and implemented balanced output circuit.