Audio M10 Signature User Manual

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M10 Signature

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REFERENCE

LINE LEVEL

PRE AMPLIFIER

OWNER’S INFORMATION

1) IMPORTANT SAFETY INFORMATION

2) CE DECLARATION OF CONFORMITY
DISPOSAL
POWER REQUIREMENTS

3) INTRODUCTION

4) OVERVIEW

5) AN INTRODUCTION FROM THE DESIGNER

8) UNPACKING AND INSTALLATION

9) CONNECTION

17) OPERATION

19) TECHNICAL SPECIFICATIONS

20) WARRANTY INFORMATION

21) CONTACT INFORMATION

CONTENTS

OTHER SAFETY PRECAUTIONS: -

Never touch the power cord with wet hands.

Always remove the power cord by grasping the plug, not the cable.

Never expose the unit to excessive heat or magnetism.

Never let an inexperienced person repair or reassemble the unit.

Never put anything, especially metal objects, inside the unit.

Never place excessive weight on the unit.

Do not store or operate this unit in areas of high humidity or in close
proximity to water / moisture.

Do not expose or immerse the unit in liquid of any kind.

This product generates high levels of heat. Adequate ventilation must
be provided. Do not restrict airflow through any ventilation slots or
place the unit on any surface that may restrict airflow.

Valve equipment operates at extremely high temperatures;

KEEP OUT OF THE REACH OF CHILDREN AND ANIMALS.!

RISK OF SHOCK OR ELECTROCUTION! INTERNAL OPERATING
VOLTAGES ARE LETHAL!

Do not remove top cover, unless specifically instructed to do so in the user
manual.

This unit contains fuses and other safety components in accordance with
BS60065 requirements.
In the event of failure, replacement fuse or safety component must be of
the same part type and value.

This product must be earthed – ensure that the mains supply cable earth /
ground is correctly connected.

SUCH REPLACEMENT MUST ONLY BE CARRIED OUT BY A
QUALIFIED SERVICE TECHNICIAN.

Do not attempt to replace any fuses without first disconnecting the unit
from the mains electricity supply.

! IMPORTANT SAFETY INFORMATION !

POWER REQUIREMENTS

Power requirements for electrical equipment vary depending on your geographical
location. Please ensure that your unit meets the power requirements in your area.
The power requirement for your unit is marked on the serial number plate, located on
the rear panel.

If you are in doubt, please contact your dealer before plugging the unit into the mains
supply.

CE DECLARATION OF CONFORMITY

DISPOSAL

This product must not be disposed of as normal household waste. To
prevent possible harm to the environment please separate the product
from other waste to ensure that it can be recycled in an environmentally
safe manner. Please contact your retailer or the appropriate local
government office for collection facilities.

We declare under our sole responsibility that this product is in conformity
with the following standards or standardized documents:

BS EN 60065 in accordance with the regulations 73/23/EEC, 89/336/EEC
(from 1 January 1997)

CE 94

Peter Qvortrup,
Director
Audio Note (UK) Limited
25 Montefiore Road
Hove
East Sussex
BN3 1RD
United Kingdom

Tel: [phone]
Fax: [phone]

Thank you for purchasing this Audio Note (UK) product. With the correct care it
should give you many years of pleasure and enjoyment.

Please take the time to read all of the information in this manual before connecting
your new component to an electrical supply or your system, to ensure both your
safety and satisfaction.

Please note that due to our desire to continually improve products, specifications are
subject to change without notice. Therefore it is important to refer to the manual that
is supplied with your product for the most accurate information; manuals downloaded
from our website or obtained from other sources may no longer fully apply to your
product.

If you have any questions regarding the information contained within this document
or your new component, please feel free to contact us: -

Audio Note (UK) Limited

25 Montefiore Road

Hove

East Sussex

BN3 1RD

United Kingdom

Tel: [phone]
Fax: [phone]

e-mail: [e-mail]

INTRODUCTION

Congratulations on your purchase of the Audio Note (UK) M10 Signature
Pre Amplifier. It is without doubt or question, the finest Line Level preamplifier in
production today, and is a full Audio Note (UK) Level 5 product. No other preamplifier
has ever managed to retrieve such incredible levels of detail, resolution and sheer
musicality from your recorded music collection. Its performance will astound and
amaze you, and invite you into a world of musical experience that you had previously
only imagined.

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 M10 Signature preamplifier 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 base anomalies, rather than producing
vanishingly small harmonic or low intermodulation distortion measurements. These
non-harmonic amplitude and time base 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 M10 Signature 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 M10 Signature
preamplifier 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.

The M10 Signature features two pairs of correctly engineered balanced / XLR inputs
for sources with suitable balanced outputs. Each input is connected directly to an in­house custom designed and produced, silver wired input transformer, which offers
the finest possible input for your XLR Line level source outputs.

Each channel is powered by an independent external power supply, based on the
Galahad design, first used in the standard M10 Line preamplifier. The M10 Signature
version takes this design and improves on it significantly; more about the design
concept of this and the rest of the M10 Signature circuit can be found in the section
below entitled “An Introduction from the Designer”.

As one would expect, the output transformers for the M10 Signature are the finest
possible examples we can produce. Each transformer is fully silver wound, and
feature our own 55% nickel iron C-Cores.

M10 SIGNATURE PRE AMPLIFIER

Andy Grove, Designer in Chief for Audio Note (UK) explains some of the
development process behind our new statement line stage: -

"I realised the core concept of the M10 power supply "Galahad" while I was doing
some theoretical work on amplifier topologies. I was analysing compound amplifiers
which are connected by bridge circuits, or in other ways, such that one amplifier will
correct the output of the other by subtracting distortion from the output. QUAD
"Current Dumping" is one such configuration of the many possible.

What I came to think was that, theoretically at least, one could build a simple circuit
using a single valve which could completely reject not only all voltage fluctuations
from the mains, but which would, to all intents and purposes, be entirely isolated from
the mains in every way. Not only that but the output impedance of the supply would
be fixed, even across the audio band, and all this would be achieved without high
feedback or complex "engineer's ego trip" solutions with hundreds of active devices.

The way this would work, essentially, is that I would use a shunt valve to look ahead
at the incoming fluctuations, and to pass a current such that the fluctuations are
completely removed. This isn't possible with a feedback topology; for feedback to
work there must necessarily be an error to correct. The circuit looks at the error at the
output and tries to correct it; therefore there must be an error at the output.

The problem with the kind of setup I was looking at implementing was that they
require extremely tight tolerances to work, and valves generally do not provide that,
they age and there is sample-to-sample variation. This was the downfall of these
schemes in the past – when the circuit drifted off balance then what you are left with
is often worse that where you started.

What I realised is that by juggling the arrangement of resistors and the valve
transconductance I could eliminate, or at least minimise, the effect of drift and ease
up the effect of component tolerances, thereby creating a practical PSU topology.

The question might be asked, "well, why not just use a conventional power supply?"
The answers to that question are: -

1) All components inject colourations – even the best components.

2) PSU capacitors tend to damp musical dynamics.

3) A conventional PSU has an uneven impedance across the audio band.

I saw that the new Galahad configuration had the potential to bypass the above
problems, and I knew within my heart or sixth sense that it would work and sound
good. I'd had experience with lesser versions of it in the past, and they were very
promising, and here I was looking at the ultimate configuration.

AN INTRODUCTION FROM THE DESIGNER