Audio Note COBRA Instruction Manual

COBRA
OWNER’S INFORMATION
INTEGRATED AMPLIFIER

CONTENTS
IMPORTANT SAFETY INFORMATION ……………………………………….…3
CE DECLARATION OF CONFORMITY……………………………………......... 4
DISPOSAL ………………………………………………………..……………….…4
POWER REQUIREMENTS……………………………………..…….……….……4
INTRODUCTION……………………………………..…………………………….. 5
AUDIO NOTE COBRA……..…………………………………………………….…6
UNPACKING AND INSTALLATION……………………………………………..…6
VALVE INSTALLATION…………………………………………………………..…7
CONNECTION………………………………………………………………………..9
OPERATION………………………………………………………………………...10
TECHNICAL SPECIFICATIONS…………………………………………............12
WARRANTY INFORMATION………………………………………………….…..13
CONTACT INFORMATION………………………………………………………..14

RISK OF SHOCK OR ELECTROCUTION! INTERNAL OPERATING
VOLTAGES ARE LETHAL!
Do not open the chassis, 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.
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.
This product must be earthed –ensure that the mains supply cable earth /
ground is correctly connected.
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.
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.
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.
! IMPORTANT SAFETY INFORMATION!

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
Viscount House
Star Road, Star Trading Estate
Partridge Green
West Sussex
RH13 8RA
United Kingdom
Tel: [phone]
Fax: [phone]
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.
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 connecting the unit to the mains
supply.
CE DECLARATION OF CONFORMITY

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
Viscount House
Star Road, Star Trading Estate
Partridge Green
West Sussex
RH13 8RA
United Kingdom
Tel: [phone]
Fax: [phone]
e-mail: [e-mail]
INTRODUCTION

Congratulations on your purchase of the Audio Note (UK) COBRA Integrated
Amplifier.
It is a Push Pull, Pure Class A valve design, offering an outstanding level of
performance and value.
It has been specifically engineered for sonic performance rather than technical
specification, and fulfills all Audio Note (UK) Level 1 criteria: -
Pure Class A Push-Pull Pentode operation
Materials and component quality
An input stage consisting of 2 x 6UA6 and 2x 5670 feeds the push-pull configured
EL34 output valves, two of which are used per channel.
The C-core output transformers are custom designed and manufactured by Audio
Note (UK) and are of extremely high quality, offering outstanding, class leading
performance.
The power supply is a multi element design with choke smoothing, ensuring precise
operation of each circuit stage, whilst a separate DC supply feeds the valve
filaments.
Please take care when unpacking your COBRA Integrated Amplifier. Choose a
clean, clear location to unpack your unit. Be aware that the amplifier is very heavy;
before attempting to unpack or lift the unit, check the weight and if necessary use
more than one person,so that it can be moved safely and easily.
We recommend that you retain and carefully store all of the original packing
materials in case transportation / shipping is required at a later date.
Select a suitable location for the unit. This should be a dry, dust free and level area,
preferably shielded from direct sunlight and free from vibration. Also ensure that the
location is stable and capable of carrying the weight of the unit.
A suitable mains power outlet must be close to the location; power cords must not be
pulled or stretched tightly in an attempt to reach a wall socket. If the power cord will
not easily reach the socket, choose a closer location!
Please ensure that adequate ventilation for the unit is provided, and that airflow
through any ventilation slots in the unit is not restricted. We recommend a distance of
at least 30cm free space is maintained above the unit. Please also remember that
valve equipment operates at extremely high temperatures, so a position that is
inaccessible to any children or animals is essential.
AUDIO NOTE COBRA
UNPACKING AND INSTALLATION

The amplifier is shipped without the valvesinstalled. It is necessary to install all
valves before the amplifier can be connected to the mains supply and operated.
It is essential that the valves are installed correctly or serious damage that is
not covered by the warranty will result. We recommend that your dealer
perform this procedure for you if you are in any way unsure.
FIRSTLY, ENSURE THAT THE AMPLIFIER IS NOT CONNECTED TO A
MAINS ELECTRICAL SUPPLY, AND THAT THE POWER CORD IS NOT
CONNECTED TO THE AMPLIFIER.
Carefully unwrap all valves.
For reference, the supplied valves are as follows: -
Socket 1 –EL34
Socket 2 – EL34
Socket 3 – EL34
Socket 4 – EL34
Socket 5 –5670
Socket 6 –5670
Socket 7 –6AU6
Socket 8 –6AU6
Once again, please understand that it is absolutely vital these valves are
fitted correctly.
Look at the drawing of the COBRA on the next page and familiarize yourself with the
positions of the various valves. First install the EL34 valves, which should be
inserted into sockets ‘1’, ‘2’, ‘3’ and ‘4’. Locate the rib on the central pin of the valve
base and align with the valve socket (it can only be inserted one way due to this
locating rib) and with gentle but firm pressure insert the valve.
Next, insert the four small signal valves into the front four sockets.
Looking from the front of the amplifier, insert the shorter 5670 valves into the outer
sockets ‘5’ and ‘6’, and the taller 6AU6 valves into the inner sockets ‘7’ and ‘8’. The
valves can only be inserted one way.
Check once again that all valves are correctly installed.
VALVE INSTALLATION

VALVE 1, 2, 3, 4 - EL34
VALVE 5, 6 - 5670
VALVE 7, 8 - 6AU6
VALVE INSTALLATION Continued…

Line inputs Three line level inputs are available, labeled ‘A1’, ‘A2’ and ‘A3’,
located on the right hand side of the rear panel.
Digital inputs The COBRA is equipped with 3 digital inputs:
‘D1’ – USB B-type, for connection to a source with a USB output
‘D2’ – TOSLINK Optical digital
‘D3’ – Coaxial digital
Ground Post A ground post is provided for connection to those source
components that also use a separate ground terminal.
Speakers Each channel is equipped with 2colour coded binding posts for
connection to your speakers.
Looking from the front of the amplifier, the 2binding posts to the left
are for the left channel and the 2binding posts to the right are for
the right channel.
Connect the amplifier’s black speaker output binding post marked as
“ –“ to the black / negative terminal (also marked “ –“) on the
speaker.
Connect the amplifier’s red speaker output binding post marked “ + “
to the red / positive terminal (also marked “ + “) on the ‘speaker.
Mains in The COBRA is equipped with an IEC 320 mains inlet socket. Use
the supplied mains cable to connect the unit to the local mains
supply. The mains fuse is located in the fuse holder positioned to the
right of the mains inlet socket on the rear panel.
Fuse The mains fuse and a spare are located in the compartment next
to the mains switch on the rear panel.
CONNECTION

Special Note –Make sure that all connections are tight and clean. For best results
use good quality audio interconnects. For best results and performance, we
recommend our own Audio Note (UK) range of interconnects and loudspeaker
cables. For further information, please consult your nearest Audio Note (UK) dealer,
or alternatively please feel free to contact us directly.
Once all connections are completed and checked, ensure that the volume control is
at the minimum setting (rotated all the way to the left).
Turn on any source components (CD player, DAC, Phono stage etc.) BEFORE
turning on the amplifier; the amplifier should be the LAST item to be turned on
when you are ready to listen to your system, and the FIRST item to be turned
off when the listening session is over.
Turn on the amplifier by using the rocker switch located on the top / right of the rear
panel, next to the mains inlet socket.
One of the red front panel lightsshould now be lit. The amplifier requires
approximately two minutes to initialize before it is ready for operation.
Input Selector Turn the input selector knob until the light of the source you
wish to listen to lights up.
Volume Control This control adjusts the listening level, or loudness. Set as
desired!
Inputs, Volume and Mute can be also controlled with the supplied remote control
handset.
When Mute is selected, input light flashes.
OPERATION

Bedding in The new amplifier requires roughly 200 hours of initial use
(called “bedding in”) before the circuitry becomes stable and
optimum performance is realized.
As the amplifier “beds in” the sound will become increasingly
more smooth, detailed and open.
Once the amplifier has “bedded in” a warm up time of
approximately 30 to 45 minutes is required each time the
amplifier is switched on before optimum sonic performance is
reached.
Cleaning No special maintenance is required for the amplifier. Use a
soft, clean lint free cloth to remove any surface marks from the
casework. For finger marks / grease, use a soft, clean lint free
cloth, lightly moistened with a solution of warm water and mild
detergent. Do not use any alcohol or solvent based cleaning
products, as they may damage the finish of the amplifier.
ENSURE THAT THE AMPLIFIER IS SWITCHED OFF AND
DISCONNECTED FROM THE MAINS ELECTRICITY
SUPPLY BEFORE UNDERTAKING ANY CLEANING.
Valve Life The valves supplied with your amplifier should provide
approximately 6000 hours of operation. They are specially
selected by us, and should only be replaced with matched
pairs. Please consult your Audio Note (UK) dealer should your
valves need replacing.
OPERATION continued…

INPUT IMPEDANCE
100K ohm, line level
INPUT SENSITIVITY
300mV for full output
MAXIMUM OUTPUT
27 watts RMS per channel into 8Ohm
loads
CHANNEL BALANCE
+/-0.3dB
VALVE COMPLEMENT
2x EL34
2x 5670
2x 6AU6
FUSE RATING
110 / 120V supply:
1 x 3.15Aanti-surge
220 / 240V supply:
1 x 1.6mA anti-surge
UNIT WEIGHT
13.6 KG
SHIPPING WEIGHT
(ORIGINAL PACKAGING)
15 KG
UNIT DIMENSIONS
180mm (h) x 340mm (w) x 450mm (d)
SHIPPING DIMENSIONS
(ORIGINAL PACKAGING)
260mm (h) x 420mm (w) x 540mm (d)
SUPPORTED SAMPLING
FREQUENCIES
(DIGITAL INPUTS)
USB: up to 16-bit/48kHz
Optical TOSLINK: up to 24-bit/96kHz
COAX: up to 24-bit/176kHz
MAX. POWER CONSUMPTION
175 Watts
NOTE
Due to Audio Note (UK)’s ongoing
research and development program,
specifications are subject to change
without notice.
TECHNICAL SPECIFICATIONS

Audio Note (UK) warrants this product to be free from defects in materials and
workmanship for two years from the original date of purchase from an appointed
Audio Note (UK) dealer, and agrees to covers the cost of parts and associated
labour required to correct such defects, subject to terms & conditions.
This Warranty is offered to the first purchaser only.
Any valves supplied with the unit are warranted for three months from the original
date of purchase.
If the product fails in normal domestic use and during the Warranty period due to the
above described faults or defects, Audio Note (UK) will, at its discretion, repair or
replace the item free of charge within a reasonable time once it has been returned to
Audio Note (UK) or an appointed Audio Note (UK) dealer or service engineer.
Audio Note (UK) is not liable for any shipping charges incurred whilst transporting the
product to or from Audio Note (UK) or an appointed Audio Note (UK) dealer or
service engineer, should the item require service or repair during or after the
Warranty period.
If the product must be shipped, please use the original packaging materials and
include a copy of the original sales receipt along with a note explaining, in as much
detail as possible, the problems you are experiencing with the unit.
Only use a reputable Courier Service or Shipping Agent, and ensure that your
product is insured during transit.
Any servicing, repairs or modifications not authorized by Audio Note (UK), or
carried out by persons other than appointed Audio Note (UK) service
engineers will invalidate any warranty.
This Warranty does NOT cover: -
Damage sustained whilst in the possession of a shipping agent, retailer or consumer
and not caused as a direct result of defects in materials or workmanship.
Damage caused by normal wear and tear.
Damage or defects caused by abnormal or unreasonable use.
Damage caused by accident, acts of nature, misuse or neglect.
Damage caused by a failure to follow the operating and installation instructions
supplied with the product.
Damage caused by improper or careless cleaning.
Audio Note (UK) reserves the right to refuse warranty for any component of which
the serial number has been removed, defaced or tampered with.
WARRANTY INFORMATION

If in the future your Audio Note (UK) product
requires servicing, or if you require technical support
or have any questions regarding this or any of our
other products, please contact your local
Audio Note (UK) dealer.
Alternatively, please feel free to contact us directly: -
Audio Note (UK) Limited
Viscount House
Star Road, Star Trading Estate
Partridge Green
West Sussex
RH13 8RA
United Kingdom
Tel: [phone]
Fax: [phone]
e-mail: [e-mail]
www.audionote.co.uk
Audio Note (UK) Ltd
CONTACT INFORMATION