Audio Note M5 RIAA Technical manual
M5 RIAA
Owner’s Information
The M5 RIAA is a Level 3RIAA phono stage,
developed for the best possible sonic performance rather
than technical specifications. To this end, the M5 RIAA
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 M5 RIAA features a 6072A phono stage, a 6X5 valve rectified power supply
based on the M10’s Galahad PSU, tantalum resistors, Black Gate filter capacitors, and
Audio Note copper foil signal capacitors, HiB c-core output transformers and a
balanced output.
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 M5 RIAA 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.
Connections
Please ensure that the M5 RIAA, the power amplifier and any source equipment is
switched off before making any connections.
NOTE: It is important that all connections are firm, secure and airtight; any
oxidisation of the interconnects will result in loss of performance. Always use high
quality interconnects; Audio Note interconnects are recommended, as they are
manufactured to the same exacting standards as all of our products.
Inputs
The M5 RIAA has one phono input, which consists of a pair of RCA connectors,
colour coded red for the right channel and white for the left channel.
The input is suitable for connection to a turntable with a moving magnet (MM) type
cartridge. Turntables with moving coil (MC) type cartridges will require a step-up
transformer between the turntable and the pre-amplifier; Audio Note produce some of
the best step-up transformers available.
Outputs
The M5 RIAA provides two unbalanced outputs; again, these outputs consist of a pair
of colour coded RCA connectors. The two outputs are for connections to a line level
pre-amplifier and are identical, making them suitable for biwiring.
Ground Post
A ground connection is provided to assist in the elimination of any ground loops that
may occur. A ground loop can be identified by excessive background hum. If you
experience a ground loop, try connecting the ground connection with that of other
system components. If the hum persists, contact your dealer.
Mains Power
An IEC power connector is located on the back of the M5 RIAA. Use the supplied
power cable to connect the pre-amplifier to the mains supply. Ensure the power is off
at the switch when you do this.
Using the M5 RIAA
Once all the connections are completed and checked, make sure all power amplifiers
are off and flip the mains rocker switch located on the back panel of the pre-amplifier
to the 'on' position.
The M5 RIAA is a vacuum tube design and therefore requires about 45 seconds
warm-up time. After this the remaining system components may be turned on.
NOTE: Always turn the phono stage on before turning on the pre-amplifier and
always turn the pre-amplifieroff before turning off the phono stage. This will prevent
any buzzing or popping sounds from occurring.
No further action is required, the M5 RIAA will act silently as a dedicated phono
stage, volume and balance adjustment etc. can be made on the line stage pre-
amplifier.
The M5 RIAA will improve over time and will start to sound increasingly well
balanced. This is because of the “bedding in” time taken by new electrical
components inside the unit. Also, the pre-amplifier’s sound quality improves as the
unit reaches its normal, stable operating temperature. Only a rear panel on/off switch
is provided as the unit is designed for continuous operation. The M5 RIAA need not
be switched off each time after use. It is interesting to note that continuous operation
not only results in optimum sonic performance (since the unit is maintaining a
constant operating temperature) but also causes less electrical stress and so extends
component and valve life.
Cleaning
Cleaning the pre-amplifier is best done with a soft brush -some photographic stores
are able to provide suitable brushes. Alternatively, a soft cotton cloth may be used
with a mild propriety cleaner for removing dirt build-up. Strong or alcohol based
solvents may damage the finish of this product. Ensure the pre-amplifier is switched
off and cold when cleaning. Do not wet the unit.
Replacing and Upgrading the Valves
Replacement NOS valves can be purchased from Audio Note when valves fail or
should you wish to experiment with different types of valves. A list of valves and
equivalents can be found at www.audionote.co.uk. Contact your dealer if you are
unsure what valves you should use or how to install them.
Line and phono stage valves should provide you with 5 years of continuous operation,
rectifier valves should last much longer.
Warranty and Servicing
Audio Note warrants that this product will be free from defects in materials and
workmanship for one year from the original date of purchase from an appointed
Audio Note dealer. The valves are warranted for three months.
In the event that your Audio Note product requires servicing, please contact your
Audio Note dealer. If the component needs to be shipped, please use the original
packaging materials and include a copy of the sales purchase with a note, explaining,
in as much detail as possible, the problems that your are experiencing with the unit.
Any modification not authorised by Audio Note will invalidate any warranty.
If you require technical support or have any questions, please direct them to your
local Audio Note dealer or alternatively contact us directly at:
Customer Support
Audio Note (UK) Limited
25 Montefiore Road
HOVE
East Sussex
BN3 1RD
United Kingdom
TEL: +44 (0)1273 220511
FAX: +44 (0)1273 731498
Specifications
Weight 7kg
Dimensions 135(h) x 440(w) x 410(d) mm
Max Power Consumption 30W
Fuse Ratings 1A anti-surge (110/120 V supply)
400mA anti-surge (220/240 V supply)
Input Impedance 47kO
Gain @ 1kHz 37dB
Max Output (rms) 28V
Output Impedance < 5kO
Tube Compliment 2x 6X5, 2x ECL82, 2x OB2, 3x 6072A
NOTE: Due to Audio Note’s ongoing research and development programme,
specifications are due to change without notice.
Safety Information
HEAT: By the nature of vacuum tubes, this product generates high levels of
heat. Adequate ventilation must be provided. Do not restrict the airflow
through any of the ventilation slots or place the amplifier on any surface that
may restrict airflow.
CAUTION: The vacuum tubes and other nearby parts operate at extremely
high temperatures -KEEP OUT OF REACH OF CHILDREN.
HUMIDITY: Do not store or operate this unit in areas of high humidity or in
close proximity to water. Do not expose the unit to liquid.
EARTHING: The product must be earthed -ensure that the mains supply cable
is earthed.
SAFETY COMPONENTS: Internal fuses and other safety components are
located inside this unit in accordance with BS 60065 requirements. In the
event of component failure, replacements must be of the same part type. Such
replacements must be carried out by a qualified service technician.
SHOCK: Internal operating voltages are lethal. Do not remove the top cover.
Do not replace fuse without first disconnecting the unit from the mains
supply.
This product complies with CE standards
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