Kramer 903 User manual

Kramer Electronics, Ltd.
USER MANUAL
Model:
903
Personal Stereo Amplifier

Contents
i
Contents
1 Introduction 1
2 Getting Started 1
3 Your Personal Stereo Amplifier 1
4 Using the Personal Stereo Amplifier 4
4.1 Connecting the Personal Stereo Amplifier 4
4.2 Operating the Personal Stereo Amplifier 4
5 Technical Specifications 6
Figures
Figure 1: 903 Personal Stereo Amplifier 3
Figure 2: Connecting the 903 Personal Stereo Amplifier 5
Tables
Table 1: Features and Functions of the 903 Personal Stereo Amplifier 3
Table 2: Technical Specifications of the 903 Personal Stereo Amplifier 6

Introduction
1
1 Introduction
Dedication by Kramer Electronics since 1981, to the development and
manufacture of high quality video/audio equipment, makes the Kramer line
an integral part of the finest production and presentation facilities in the
world. In recent years, Kramer has redesigned and upgraded most of the line,
making the best even better! The Kramer line of professional video/audio
electronics is one of the most versatile and complete available, and is a true
leader in terms of quality, workmanship, price/performance ratio and
innovation. In addition to our high quality accessories, like the Kramer
TOOLS 903 Personal Stereo Amplifier, we also offer excellent switchers and
matrices, distribution amplifiers, presentation processors, interfaces, remote
controllers and computer-related products. Congratulations on purchasing
your Kramer 903 Personal Stereo Amplifier. This product is ideal for:
 Presentation rooms and multimedia applications for quick, local audio
amplification
 Personal audio listening (for example, PC and portable CD player)
The package includes the following items:
 903 Personal Stereo Amplifier
 Power adapter (12V DC Input)
 This user manual
1
2 Getting Started
We recommend that you:
 Unpack the equipment carefully and save the original box and packaging
materials for possible future shipment
 Review the contents of this user manual
3 Your Personal Stereo Amplifier
The high performance 903 Personal Stereo Amplifier can output up to
20 Watts RMS
2
, as it uses the latest Class “D” technology for highly efficient
conversion
3
to the pair of loudspeakers with the absolute minimum power
loss.
1 Download up-to-date Kramer user manuals from the Internet at this URL: http://www.kramerelectronics.com/manuals.html
2 More than is needed for personal and small presentation applications
3 This prevents the 903 from over-heating. The 903 can generate its maximum power output from a 12V power supply

Your Personal Stereo Amplifier
KRAMER ELECTRONICS, LTD.
2
The 903 includes:
 Control knobs to adjust volume, bass, mid, treble and stereo balance
 4 INPUT SELECTOR switches
 Outputs for a headphone set and for a pair of loudspeakers
1
 3 stereo inputs on standard RCA connectors
 An additional input on a mini 3.5 mm socket for easy interface with a
sound card or any music player
2
 A LOUD switch for automatic equalization in low volume listening
3
Achieving the best performance means:
 Connecting only good quality connection cables, thus avoiding
interference, deterioration in signal quality due to poor matching, and elevated
noise levels (often associated with low quality cables)
 Avoiding interference from neighboring electrical appliances and
positioning your Kramer 903 away from moisture, excessive sunlight and dust
1 Plugging in the headphone set automatically disconnects the loudspeakers
2 Portable CD player, minidisk player, Walkman®
3 Pressing the LOUD switch compensates for what the ear does not hear in noisy environments, or with a low volume.
Pressing the LOUD switch with a high volume has little effect

Your Personal Stereo Amplifier
3
Figure 1 and Table 1 define the 903 Personal Stereo Amplifier:
Figure 1: 903 Personal Stereo Amplifier
Table 1: Features and Functions of the 903 Personal Stereo Amplifier
# Feature Function
1 12V DC +12V DC connector for powering the unit
2 SPEAKERS OUT (L+L- R+R-)
Terminal Block Connectors
Connect to the pair of loudspeakers
3 INPUT 4 (Left) RCA Connector Connects to the left stereo audio line level source 4
4 INPUT 4 (Right) RCA Connector Connects to the right stereo audio line level source 4
5 INPUT 3 (Left) RCA Connector Connects to the left stereo audio line level source 3
6 INPUT 3 (Right) RCA Connector Connects to the right stereo audio line level source 3
7 INPUT 2 (Left) RCA Connector Connects to the left stereo audio line level source 2
8 INPUT 2 (Right) RCA Connector Connects to the right stereo audio line level source 2
9 INPUT 1 Mini 3.5 mm Socket Connects to an interface with a sound card or other player
10
INPUT SELECTOR Switches Pushing in selects the appropriate input (from 1 to 4)
11
Treble Control Knob Controls the treble (high frequencies)
12
MID Control Knob Controls the mid frequencies
13
Bass Control Knob Controls the bass (low frequencies)
14
Volume Control Knob Controls the signal output level
15
Balance Control Knob Adjusts the balance between the right and left channels
16
LOUD Switch Boosts equalization for low volume listening environments
17
ON LED Illuminates when receiving power
18
PHONES connector Connects to the headphone set

Using the Personal Stereo Amplifier
KRAMER ELECTRONICS, LTD.
4
4 Using the Personal Stereo Amplifier
Sections 4.1 and 4.2 describe how to connect and how to operate your 903
Personal Stereo Amplifier, respectively.
4.1 Connecting the Personal Stereo Amplifier
Connect your 903, as the example in Figure 2 illustrates:
1. Connect a stereo audio source to the Left and Right RCA connectors for
up to 3 inputs (that is, INPUT 2, INPUT 3 and INPUT 4)
1
2. Connect a music player to the 3.5 mm socket (INPUT 1)
1
3. Connect one or both of the following outputs:
 The SPEAKERS OUT connector to a pair of loudspeakers, by connecting
the left loudspeaker to the “L+” and the “L-” terminal block connectors, and
the right loudspeaker to the “R+” and the “R-” terminal block connectors
Do not Ground the loudspeakers
 The PHONES connector to a headphone set (plugging in a headphone set
to the PHONES connector disconnects the loudspeakers)
4. Connect the 12V DC power adapter to the power socket and connect the
adapter to the mains electricity.
4.2 Operating the Personal Stereo Amplifier
Operate your 903, as Figure 2 illustrates:
1. Choose the active audio source via an INPUT SELECTOR switch.
2. Adjust the volume, bass, mid, treble and balance controls as required.
3. Select the LOUD switch setting as required.
1 Unused inputs may be left unconnected

Using the Personal Stereo Amplifier
5
Figure 2: Connecting the 903 Personal Stereo Amplifier

Technical Specifications
KRAMER ELECTRONICS, LTD.
6
5 Technical Specifications
Table 2: Technical Specifications
1
of the 903 Personal Stereo Amplifier
Inputs: 3 stereo inputs on RCA connectors
1 stereo input on mini 3.5 mm socket
Outputs: Stereo loudspeakers (4speakers or higher) on terminal block; Headphones
Bandwidth: 20 kHz -3dB
S/N Ratio: 77 dB unweighted
THD + Noise: 0.5% @ 1kHz, 60mV
Controls: 4 input selector switches, volume, bass, mid, treble and balance control knobs
Output Power: Up to 20 Watts RMS
Dimensions: 12 cm x 7.5 cm x 2.5 cm (4.7" x 2.95" x 0.98", W, D, H)
Power Source:
12 VDC, 2.5A
Weight: .3 kg (0.66lbs.) approx.
Accessories: Power supply, mounting bracket
1 Specifications are subject to change without notice

7
LIMITED WARRANTY
Kramer Electronics (hereafter Kramer) warrants this product free from defects in material and workmanship under the
following terms.
HOW LONG IS THE WARRANTY
Labor and parts are warranted for three years from the date of the first customer purchase.
WHO IS PROTECTED?
Only the first purchase customer may enforce this warranty.
WHAT IS COVERED AND WHAT IS NOT COVERED
Except as below, this warranty covers all defects in material or workmanship in this product. The following are not covered
by the warranty:
1. Any product which is not distributed by Kramer, or which is not purchased from an authorized Kramer dealer. If you are
uncertain as to whether a dealer is authorized, please contact Kramer at one of the agents listed in the web site
www.kramerelectronics.com.
2. Any product, on which the serial number has been defaced, modified or removed.
3. Damage, deterioration or malfunction resulting from:
i) Accident, misuse, abuse, neglect, fire, water, lightning or other acts of nature
ii) Product modification, or failure to follow instructions supplied with the product
iii) Repair or attempted repair by anyone not authorized by Kramer
iv) Any shipment of the product (claims must be presented to the carrier)
v) Removal or installation of the product
vi) Any other cause, which does not relate to a product defect
vii) Cartons, equipment enclosures, cables or accessories used in conjunction with the product
WHAT WE WILL PAY FOR AND WHAT WE WILL NOT PAY FOR
We will pay labor and material expenses for covered items. We will not pay for the following:
1. Removal or installations charges.
2. Costs of initial technical adjustments (set-up), including adjustment of user controls or programming. These costs are the
responsibility of the Kramer dealer from whom the product was purchased.
3. Shipping charges.
HOW YOU CAN GET WARRANTY SERVICE
1. To obtain service on you product, you must take or ship it prepaid to any authorized Kramer service center.
2. Whenever warranty service is required, the original dated invoice (or a copy) must be presented as proof of warranty coverage,
and should be included in any shipment of the product. Please also include in any mailing a contact name, company, address, and
a description of the problem(s).
3. For the name of the nearest Kramer authorized service center, consult your authorized dealer.
LIMITATION OF IMPLIED WARRANTIES
All implied warranties, including warranties of merchantability and fitness for a particular purpose, are limited in duration to
the length of this warranty.
EXCLUSION OF DAMAGES
The liability of Kramer for any effective products is limited to the repair or replacement of the product at our option. Kramer
shall not be liable for:
1. Damage to other property caused by defects in this product, damages based upon inconvenience, loss of use of the product, loss
of time, commercial loss; or:
2. Any other damages, whether incidental, consequential or otherwise. Some countries may not allow limitations on how long an
implied warranty lasts and/or do not allow the exclusion or limitation of incidental or consequential damages, so the above
limitations and exclusions may not apply to you.
This warranty gives you specific legal rights, and you may also have other rights, which vary from place to place.
NOTE: All products returned to Kramer for service must have prior approval. This may be obtained from your dealer.
This equipment has been tested to determine compliance with the requirements of:
EN-50081: "Electromagnetic compatibility (EMC);
generic emission standard.
Part 1: Residential, commercial and light industry"
EN-50082: "Electromagnetic compatibility (EMC) generic immunity standard.
Part 1: Residential, commercial and light industry environment".
CFR-47: FCC Rules and Regulations:
Part 15: “Radio frequency devices
Subpart B – Unintentional radiators”
CAUTION!
Servicing the machines can only be done by an authorized Kramer technician. Any user who makes changes or modifications to
the unit without the expressed approval of the manufacturer will void user authority to operate the equipment.
Use the supplied DC power supply to feed power to the machine.
Please use recommended interconnection cables to connect the machine to other components.

Kramer Electronics, Ltd.
Web site: www.kramerelectronics.com
E-mail: inf[email protected]
P/N: 2900-006014 REV 2
For the latest information on our products and a list of Kramer
distributors, visit our Web site: www.kramerelectronics.com.
Updates to this user manual may be found at
http://www.kramerelectronics.com/manuals.html.
We welcome your questions, comments and feedback.