Kramer 914 User manual

KRAMER ELECTRONICS LTD.
PRELIMINARY
USER MANUAL
MODEL:
914
Power Amplifier
P/N: 2900-300280 Rev 1

914 – Contents
i
Contents
1Introduction 1
2Getting Started 2
2.1 Achieving the Best Performance 2
3Overview 3
3.1 Energy Star 3
4Defining the 914 Power Amplifier 5
5Connecting the 914 7
5.1 Connecting the 914 7
5.2 Connecting the Speakers 8
5.3 Connecting a Balanced and Unbalanced Stereo Audio Input 9
6Operating the 914 10
6.1 Stereo and Bridged Mono Modes 10
6.2 Operating the 914 Remotely 10
7Technical Specifications 11
Figures
Figure 1: 914 Power Amplifier Front Panel 5
Figure 2: 914 Power Amplifier Rear Panel 6
Figure 3: Connecting the 914 Power Amplifier 8
Figure 4: Connecting Speakers to the 914 Power Amplifier 8
Figure 5: Balanced Stereo Audio Connection 9
Figure 6: Unbalanced Stereo Audio Input Connection 9

914 - Introduction
1
1 Introduction
Welcome to Kramer Electronics! Since 1981, Kramer Electronics has been
providing a world of unique, creative, and affordable solutions to the vast range of
problems that confront the video, audio, presentation, and broadcasting
professional on a daily basis. In recent years, we have redesigned and upgraded
most of our line, making the best even better!
Our 1,000-plus different models now appear in 11 groups that are clearly defined
by function: GROUP 1: Distribution Amplifiers; GROUP 2: Switchers and Matrix
Switchers; GROUP 3: Control Systems; GROUP 4: Format/Standards Converters;
GROUP 5: Range Extenders and Repeaters; GROUP 6: Specialty AV Products;
GROUP 7: Scan Converters and Scalers; GROUP 8: Cables and Connectors;
GROUP 9: Room Connectivity; GROUP 10: Accessories and Rack Adapters and
GROUP 11: Sierra Products.
Congratulations on purchasing your Kramer 914 Power Amplifier, which is ideal for
the following typical applications:
Presentation rooms and multimedia applications for local audio amplification
Personal audio listening (for example, a PC and portable CD player)

2
914 - Getting Started
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
Use Kramer high performance high resolution cables.
Use only the power cord that is supplied with this machine
Go to http://www.kramerelectronics.com/support/product_downloads.asp
to check for up-to-date user manuals, application programs, and to check if
firmware upgrades are available (where appropriate).
2.1 Achieving the Best Performance
To achieve the best performance:
Use only good quality connection cables (we recommend Kramer high-
performance, high-resolution cables) to avoid interference, deterioration in
signal quality due to poor matching, and elevated noise levels (often
associated with low quality cables)
Do not secure the cables in tight bundles or roll the slack into tight coils
Avoid interference from neighboring electrical appliances that may adversely
influence signal quality
Position your Kramer 914 away from moisture, excessive sunlight and dust
This equipment is to be used only inside a building. It may only be
connected to other equipment that is installed inside a building.
i
!

914 - Overview
3
3 Overview
The Kramer 914 is a high performance power amplifier that accepts a balanced
stereo audio input on a 5-pin terminal block and converts the signal into a
differential stereo audio output for speakers on a 4-pin terminal block.
The 914 Power Amplifier features:
An audio level knob to adjust the volume
Remote control
Stereo and bridged mono modes of operation
Independent left and right channel monitoring LEDs
Easy-to-connect, detachable terminal blocks
The 914 Power Amplifier is housed in a Kramer TOOLS enclosure.
3.1 Energy Star
The 914 Power Amplifier meets the ENERGY STAR audio specification and draws
less than 1 watt while in standby mode, offers a sleep mode, auto power-down,
and meets the specified efficiency requirements.
To comply with the Energy Star requirements the 914 provides the following
operational modes:
1. On Mode—Where the 914 is connected to a mains power source, has been
activated and is capable of providing amplification. The common terms
“active”, “in-use” and “normal operation” also describe this mode.
Active State—A state within On Mode in which the 914 provides
amplification
Standby State—A state within On Mode in which the 914 does not
provide amplification

4
914 - Overview
2. Standby Mode—Where the 914 is connected to a mains power source, is
incapable of providing amplification, and offers the following user oriented or
protective functions:
It facilitates the activation of other modes (including activation of On
Mode) by a remote switch (including remote, contact-closure switches),
and timer
The front panel’s information LEDs continuously display the unit’s status
The sensor-based functions sensor-based functions function
continuously. For purposes of this specification, Sleep Mode is defined
as the time when the product is connected to a power source, does not
produce sound, and is waiting to be switched to On Mode by a direct or
indirect signal
3. Off Mode—Where the product is connected to a mains power source, is not
providing amplification, and cannot be switched into any other mode except
by user actuation of a manual power switch.

914 - Defining the 914 Power Amplifier
5
4 Defining the 914 Power Amplifier
Figure 1 defines the front panel of the 914 Power Amplifier.
Figure 1: 914 Power Amplifier Front Panel
#
Feature
Function
1
ON LED
Lights green when the unit is powered on
2
LEFT
Channel
PROTECT LED
Lights red when the left channel signal protection is
activated
CLIP LED
Lights yellow when the left channel signal is clipping
SIGNAL LED
Lights green when there is a signal present on the left
channel
3
RIGHT
Channel
PROTECT LED
Lights red when the right channel signal protection is
activated
CLIP LED
Lights yellow when the right channel signal is clipping
SIGNAL LED
Lights green when there is a signal present on the right
channel

6
914 - Defining the 914 Power Amplifier
Figure 2 defines the rear panel of the 914 Power Amplifier.
Figure 2: 914 Power Amplifier Rear Panel
#
Feature
Function
1
INPUT
L+ L–G R+ R–5-pin
Terminal Block
Connect to a balanced, stereo, analog audio
source
2
LEVEL Trimmer
Turn clockwise to increase the input level and
anticlockwise to decrease the input level
3
SPEAKER
OUT
L–L+ R–R+ 4-pin
Terminal Block
Connect to the speakers (see Section Error!
Reference source not found.)
4
STEREO
BRIDGED MONO
Switch
Push switch up to operate in standard stereo
mode; push switch down to operate in
bridged mono mode (see Section Error!
Reference source not found.)
5
REMOTE
V+ LEVEL GND
STANDBY MUTE 5-pin
Terminal Block
Connect to the output level control
potentiometer (10kΩ), and the remote
Standby and Mute switches (see Section
Error! Reference source not found.)
6
ENABLE DISABLE
Switch
When the switch is up, the remote volume
control is enabled; when the switch is down,
the remote volume control is disabled
7
Mains Power
Unit
Connect to the mains power
Mains Fuse for protecting the 914
Switch for turning the device on and off

914 - Connecting the 914
7
5 Connecting the 914
This chapter comprises the following sections:
Connecting the 914 (see Section 5.1)
Connecting the speakers (see Section 5.2)
5.1 Connecting the 914
Always switch off the power to each device before connecting it to your
914. After connecting your 914, connect its power and then switch on
the power to each device.
To connect the 914 as illustrated in the example in Figure 3:
1. Connect the balanced, stereo audio source (for example, a multimedia
player) to the INPUT 5-pin terminal block (see Section 5.3).
2. Connect the Speaker Out terminal block to a pair of speakers. Connect the
left speaker to the L+ and L–pins, and the right speaker to the R–and R+
pins (in stereo mode). For bridged mono mode, see Section 5.2.
Note: Do not ground the speakers.
3. Optional—Connect the GND,LEVEL and V+ pins on the 10V CONTROL
terminal block connector to a remote 10kΩ volume control.
4. Optional—Connect the Standby and Mute pins to remote control switches
(see Section Error! Reference source not found.).
5. Connect the supplied power cord to the 914 power socket and to the mains
electricity (not shown in Figure 3).
6. Adjust the volume using the Level control on the rear panel.
i

8
914 - Connecting the 914
Figure 3: Connecting the 914 Power Amplifier
5.2 Connecting the Speakers
The 914 can be operated in either stereo or bridged-mono mode.
Note: When operated in stereo mode the speakers can be either 4Ω or 8Ω; when
operated in bridged-mono mode the speaker can only be 8Ω.
Figure 4: Connecting Speakers to the 914 Power Amplifier

914 - Connecting the 914
9
To connect speakers to the 914 in stereo mode:
Connect the L–and the L+ pins to the –and + terminals of the left speaker
respectively
Connect the R–and the R+ pins to the –and + terminals of the right speaker
respectively
To connect speakers to the 914 in bridged-mono mode:
Connect the L+ and the R–pins to the + and –terminals of the speaker
respectively
5.3 Connecting a Balanced and Unbalanced Stereo Audio
Input
This section illustrates how to wire:
A balanced, stereo audio connection, see Figure 5
An unbalanced stereo audio input connection, see Figure 6
Figure 5: Balanced Stereo Audio
Connection
Figure 6: Unbalanced Stereo Audio
Input Connection

10
914 - Operating the 914
6 Operating the 914
This chapter comprises the following sections:
Stereo and bridged-mono modes (see Section 6.1)
Operating the 914 remotely (see Section 6.2)
6.1 Stereo and Bridged Mono Modes
You can operate the 914 in either stereo or bridged mono mode. The mode is set
using the switch on the rear panel of the 914.
Note: When operated in stereo mode the speakers can be either 4Ω or 8Ω; when
operated in bridged-mono mode the speaker can only be 8Ω.
To enable bridged-mono mode:
Slide the Stereo/Bridged Mono switch on the rear panel of the 914 down
6.2 Operating the 914 Remotely
The following functions are available to operate the 914 remotely:
Output level
Standby
Mute
To put the 914 into standby mode or to mute the output:
Connect the relevant pin (Standby or Mute respectively) to the ground pin
(GND)

914 - Technical Specifications
11
7 Technical Specifications
INPUT:
1 balanced stereo +4dBu/10kΩ on a 5-pin removable
terminal block
OUTPUT:
1 stereo or bridged mono speaker output on a 4-pin
removable large terminal block
INPUT SENSITIVITY:
0.3V to 1.23V –10dBu to 4 dBu
OUTPUT POWER:
2 x 100W @ 4Ω
2 x 50W @ 8Ω
1 x 200W @ 8Ω BTL
AMPLIFIER TYPE:
Class D
MAXIMUM VOLTAGE
GAIN:
22.7dB
BANDWIDTH (-3dB):
20Hz to 20kHz
S/N RATIO:
–70dB @ 14dBu amplification
CONTROLS:
Screw trimmer for line input sensitivity; Remote 10k
trimmer; Contact-closure controls for mute and standby
AUDIO THD + NOISE:
0.05% @ 75W RMS @ 4Ω 6.67kHz
AUDIO 2nd HARMONIC:
0.08% @ 75W RMS @ 4Ω 6.67kHz
POWER SOURCE:
100240V AC, 50/60Hz, 420VA
DIMENSIONS:
21.2cm x 22.8cm x 4.3cm (8.35" x 8.98" x 1.69") W, D, H
WEIGHT:
1.0kg (2.2lbs) approx.
INCLUDED
ACCESSORIES:
Power cord, mounting bracket
OPTIONS:
RK-3T 19” rack adapter
Specifications are subject to change without notice at http://www.kramerelectronics.com

For the latest information on our products and a list of Kramer distributors,
visit our Web site where updates to this user manual may be found.
We welcome your questions, comments, and feedback.
Web site: www.kramerelectronics.com
E-mail: [e-mail]
P/N:
2900-300280
Rev:
1
!
SAFETY WARNING
Disconnect the unit from the power
supply before opening and servicing