Audio Note M1 Line User Manual

M1 Line

Owner’s Information

The M1 Line is a Level 1 line pre-amplifier, developed
for the best possible sonic performance rather than
technical specifications. To this end, the M1 Line
incorporates thermionic valve technology to produce the
most accurate sound possible and has been brought to
maturity through a development process we call
comparison by contrast, which is currently unique to
Audio Note. The article from which this technique is
based, named ‘Audio Hell’, is available from Audio
Note by request.

Please read this manual carefully in order to obtain the
best possible performance from your pre-amplifier.
Audio Note wishes you many happy years of listening
pleasure.

Technology

It is well known to any audio circuit designer worth their salt that accurate
reproduction of music relies entirely on the preservation of the purity of the incoming
signal. It is therefore not a difficult step to make to realise that the complexity of the
circuitry itself must be kept to a minimum in order to retain the musicality of the
original performance.

In response to this, all Audio Note pre-amplifiers use a single-ended, zero feedback
circuit topology. The single-ended gain stage topology is simply the most linear,
demanding pure Class A valve operation and removing the need for a phase splitter,
which introduces unnecessary crossover distortion.

The Audio Note amplifier range does not make use of any kind of feedback. As a
result, they were neither designed for vanishingly small harmonic or low
intermodulation distortions, but instead for minimal non-harmonic and time base
anomalies. It is these non-harmonic amplitude and time base distortion that have a
highly perceptible and adverse affect on the signal waveform.

Our amplifiers are designed for maximum linearity without ‘corrective’ measures to
keep transient distortions to a minimum rather than introducing the recursive errors
inherent in feedback loops.

The M1 Line features an ECC82 line stage and an upgraded form of the zero power
supply.

Unpacking & Installation

Please take care when unpacking the pre-amplifier. We recommend that you store the
packing materials in case the unit requires shipping at a later date.

Next, select a suitable location for the unit, ensuring that adequate ventilation is
provided (the valves generate a fair amount of heat). In the interest of safe, reliable
operation, situate the pre-amplifier well away from dampness or direct sunshine.
Avoid sitting the M1 Line close to any other equipment, such as a power amplifier,
that may be generating a strong magnetic field, or in close proximity to active mobile
telephones.

Worthwhile sonic improvements may be obtained by locating the unit on a
specifically designed audio component support system; we tend to prefer natural
materials such as wood.

The M1 Line is capable of driving long interconnects to power amplifiers and so, if
you are using mono block amplifiers, it may be worthwhile to locate them close to the
speakers. This will reduce the speaker cable lengths and provide sonic improvements.