OPERATING INSTRUCTIONS
A 1
Headphone Amplifier
Contents
3
1. Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Important Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Controls and Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Application Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5. Trouble Shooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6. Technical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
FCC Declaration of Conformity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
A 1 – Introduction
4
Thank you for selecting the A 1 headphone amplifier from beyerdynamic. This unit has been made from high grade
materials and assembled under stringent quality and performance conditions to provide you with an excellent product.
Please take some time to read carefully through this manual before using the product, even if you have experience
with similar devices.
Supplied accessories
• Please check if the delivery of the A 1 is complete. If any parts are missing, please contact your dealer directly,
where you purchased this product. The packaging should include the following components:
• A 1 headphone amplifier
• Power cable
• Manual
• beyerdynamic warrranty card
Why use a headphone?
There are many good reasons for using a headphone:
• With headphones music is perceived more intensely than when using loudspeakers, because the transducer are
worn directly at the ears.
• With headphones you can achieve an excellent music reproduction at a lesser price. For an appropriate loudspeaker
system you would pay much more. Regarding resolution and dynamics, high-quality headphones are comparable
to excellent loudspeakers, as these have to put more air into oscillation to achieve the same volume. The thin and
lightweight diaphragm of a headphone, however, starts to oscillate very quickly.
• With a headphone you can listen to music undisturbed, even in noisy surroundings or late at night without
disturbing the neighbourhood.
Why use a headphone amplifier?
• Integrated headphone amplifiers are often simple and inefficient operational amplifiers. Due to a high internal
noise and an insufficient performance of the original dynamics these circuits make music sound quite bland and
dreary.
• There are high-impedance headphones which need more voltage and low-impedance
models which need more power to provide excellent results. In comparison to integrated amplifiers, an external
headphone amplifier such as the A 1 features more dynamics and increases the sound quality of standard
headphones considerably.
• A headphone amplifier provides a higher volume and more powerful bass response, even with less output power.
When using a headphone and headphone amplifier, make sure that the desired volume can be achieved without
any distortions.
A 1 – Safety Information
5
1. Features
• The A 1 is a high-quality headphone amplifier which has been developed and manufactured in Germany for
headphones with a nominal impedance between 30 and 600 ohms.
• The special circuit design provides an impressing natural sound reproduction with an excellent resolution and
spatiality.
• The powerful mains adapter avoids dynamic distortions.
• Although we have developed the A 1 for use with our Premium Line headphones, you can use also headphones
of other manufacturers.
• The A 1 is ideal for very different impedances, because the high output impedance at the headphone socket
ensures that the range of the volume potentiometer remains ideal even for low-impedance transducers.
• Intelligent circuit design with microcontroller capable of 96 kHz
• Volume control with high-quality ALPS potentiometer
• Large dimensioned toroidal core transformator for high fidelity of impulse and dynamics
• Two stereo inputs for alternative sound sources
• Blue LEDs to indicate the active signal input, multicolour power LED
• Gold plated audio sockets for perfect signal transmission
2. Important safety information
• Read the Operating Instructions.
• Keep these Operating Instructions safe.
• Comply with the Operating and Safety instructions listed.
• Heed all warnings.
• Install the A 1 as described in these operating instructions.
• To avoid damage to your hearing always reduce the volume before putting the A 1 into operation and when
changing the audio source, as the connected devices or reproduced audio data can have very different output
levels.
• The A 1 is not designed for outside use. To reduce the risk of fire or electric shock, do not expose the A 1 to
rain or moisture. For this reason do not install it in the immediate vicinity of swimming pools, showers, damp
basement rooms or other areas with unusually high atmospheric humidity.
• Never place objects containing liquid (e.g. vases or drinking glasses) on the A 1. Liquids in the A 1 could cause a
short circuit.
• Only clean the A 1 with a dry cloth.
• Never install and operate the A 1 close to radiators, lighting equipment or other heat generating equipment.
• Never place naked flames near the A 1.
• Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the
point where they exit from the apparatus.
• Lay all connection cables so that they do not present a trip hazard.
• Unplug the A 1during lightning storms or when unused for long periods of time.
• Check whether the connection figures comply with the existing mains supply. Serious damage could occur due to
connecting the A 1 to the wrong power supply. An incorrect mains voltage could damage the A 1 or cause an
electric shock.
• If the A 1 causes a blown fuse or a short circuit, disconnect it from the mains and have it checked and repaired.
• Do not open the equipment without authorisation. You could receive an electric shock. Leave all service work to
authorised expert personnel.
• Do not hold the mains cable with wet hands. There must be no water or dust on the contact pins. In both cases
you could receive an electric shock.
• The mains cable must be firmly connected. If it is loose there is a fire hazard.
• Always pull out the mains cable from the mains and/or from the equipment by the plug, never by the cable. The
cable could be damaged and cause an electric shock or fire.
• The A 1 must not be operated when the mains cable is damaged.
A 1 – Controls and Indicators
6
• Do not insert objects into openings. You could damage the device and/or injure yourself.
• Refer all servicing to qualified service personnel. Servicing is required when the A 1 has been damaged in any way,
such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the A 1, the A 1
has been exposed to rain or moisture, does not operate normally, or has been dropped.
Dual-colour LED to indicate the operating state of the A 1.
Red: Stand-by, i.e. the amplifier is not active as there is no signal at the headphone socket.
The amplifier, however, is connected to the mains supply.
Green: The A 1 is ready for operation, the amplification is active. When a signal is fed into the selected input, it
is routed to the headphone socket according to volume control.
Red flashing: A technical defect of the A 1 has occurred. Please contact your beyerdynamic dealer for repair.
Button to activate / deactivate the amplification function of the A 1.
Important:
The button does not disconnect the device from the mains supply when turning off.
Unplug the device if you want to disconnect it from the mains supply. Before using the device make sure that
the mains plug is in perfect condition. If you do not use the device for a longer period of time, please unplug
the mains plug.
Headphone socket, 1/4" (6.35 mm) stereo jack, to connect standard headphones.
LED to indicate the active signal input, Input 1 or. Input 2.
The blue LED will illuminate if a signal is present.
Button to select the sound source of the A 1. Input 1 is automatically looped through to the output socket on
the rear; Input 2 can be activated, if another sound source is connected to the A 1. Refer also to chapter
5. “Application example”.
Volume control to set the volume.
Important:
We would like to point out that listening at high volumes over a long period of time may damage your hearing
irreversibly. Therefore, reduce the volume before putting into operation and when changing the audio source,
as the connected devices or reproduced audio data can have very different output levels.
Make sure that the set volume is not too high. Rule of thumb: The higher the volume, the shorter the time of
listening. According to employer’s regulations for safety and health the noise exposure e.g. when working
should not exceed 85 dB (low volume). This is an allowed time of listening of 8 hours at maximum. If the
volume is increased by 3 dB, the allowed time of listening is halved, i.e. with 88 dB the time of listening is
4 hours, with 91 dB 2 hours and so on.
3. Controls and indicators
Front view
A 1 – Controls and Indicators
7
Rear view
Input 1, stereo RCA sockets for sound sources with a high level. Connect your audio source here (CD player,
DVD player etc.)
Input 2, stereo RCA sockets for sound sources with a high level. Connect your second audio source here,
if present.
Output, stereo RCA sockets, looped-through input signal from input 1.
At this output you can pick up the audio signal from input 1 and route it to your stereo amplifier, active
loudspeakers or other devices with a standand input for high levels.
Fuse holder.
The A 1 provides a microfuse as protection against wrong voltage. If it is necessary to change the fuse, only use
the same type (350 mA T). Only this ensures an optimum protection of the circuitry.
Mains connection for 110 - 120 V AC.
A 1 – Application
8
4. Application example
A 1 with CD player and DVD player
• Connect a CD player to the input 2 of the A 1 and a DVD player to the input 1 to which you would like to
listen to alternatively with your hi-fi system (e.g. home cinema).
• To listen to the sound via headphones you can use the buttons to select the sound source (input 1 = CD player
or input 2 = DVD player). This means the A 1 provides either the audio signal of the CD player or DVD player.
• The signal of the DVD player is also permanently present at the output socket . This means you can listen to
the looped through audio signal via your hi-fi system, even when the A 1 is turned off.
• An intelligent, microprocessor-controlled relay allows noiseless switching between the two different sound sources
and avoids unpleasant noise when turning the A 1 on or off.
DVD player
Loudspeaker
Input 2
Stereo in
Stereo out Stereo out
Output
Input 1
Output
amplifier
CD player
A1
A 1 – Trouble Shooting
9
5. Trouble shooting
6. Technical specifications
Input impedance . . . . . . . . . . . . . . . . . . . . . . . 50 kΩ
Maximum amplification . . . . . . . . . . . . . . . . . . 18 dB
Frequency response . . . . . . . . . . . . . . . . . . . . . 1 Hz - 100 kHz (-1 dB)
T.H.D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.001% at 170 mW / 250 Ω
Channel separation . . . . . . . . . . . . . . . . . . . . . > 89 dB
Output power . . . . . . . . . . . . . . . . . . . . . . . . . 100 mW / 600 Ω
170 mW / 250 Ω
150 mW / 30 Ω
Unweighted signal-to-noise ratio . . . . . . . . . . . > 100 dB
Output impedances . . . . . . . . . . . . . . . . . . . . . Line Out (depending on the connected device),
100 Ω headphone output
Power consumption. . . . . . . . . . . . . . . . . . . . . < 15 W via internal, controlled power pack
Audio connections. . . . . . . . . . . . . . . . . . . . . . Headphone socket,
1 Line output,
2 Audio inputs (gold-plated RCA sockets)
Mains power input. . . . . . . . . . . . . . . . . . . . . . 110 - 120 V AC, 50/60 Hz
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 x 225 x 50 mm
Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . approx. 2.3 kg
Problem Possible cause Solution
The amplifier does not work. The
Power LED does not illuminate
although the A 1 is connected to
the mains.
The internal fuse is probably blown. Unplug the power cable of the A 1,
before changing the fuse. The fuse
holder is directly next to the
mains connection. Pull the small
cover and replace the fuse (5 x 20)
by the same type 110 - 120 V,
0.315 A, slow.
Although the headphone is properly
connected there is no sound. The
Power LED illuminates green.
Different source selected, volume
turned to minimum or defective
cable.
Check the selected audio source
and the cabling on the rear of the
A 1. Make sure that the volume is
not turned too high, as sudden
high volumes may occur which can
damage your hearing.
A 1 – FCC Declaration of Conformity
10
DECLARATION OF CONFORMITY
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two
conditions: (1) This device may not cause harmful interference, and (2) This device must accept
any interference received, including interference that may cause undesired operation.
Manufacturer: beyerdynamic GmbH & Co. KG
Theresienstrasse 8
D- 74072 Heilbronn, Germany
U.S. Responsible Party: beyerdynamic, Inc.
56 Central Avenue
Farmingdale, NY 11735, USA
Contact Person: Wolfgang Luckhardt, Managing Director
Phone: Tel. (631) 293 3200
Fax: (631) 293 3288
Model/Type: Headphone Amplifier
A1
Classification: Class B Digital Device
We hereby declare that the equipment bearing the trade name and model number specified
above was tested conforming to the applicable FCC rules under the most accurate measurement
standards possible, and that the necessary steps have been taken and are in force to assure
that production units of the same equipment will continue to comply with the Commission’s
requirements.
Manufacturer’s Signature: April 1, 2009
U. Roth, Director of R&D
Responsible Party’s Signature: April 1, 2009
W. Luckhardt, General Manager
DE 1/BA A 1 USA (04.09)/609.889/Hoh. • Non-contractual illustrations. Subject to change without notice. • Printed in Germany
beyerdynamic GmbH & Co. KG
Theresienstr. 8 | 74072 Heilbronn – Germany
Tel. +49 (0) 7131 / 617 - 0 | Fax +49 (0) 7131 / 617 - 224
[email protected] | www.beyerdynamic.de
beyerdynamic Inc. USA
56 Central Ave. | Farmingdale, NY 11735
Tel. +1 (6 31) 2 93 - 32 00 | Fax +1 (6 31) 2 93 - 32 88
[email protected] | www.beyerdynamic.com
For further distributors worldwide, please go to www.beyerdynamic.com
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