Kramer 920 User manual

KRAMER ELECTRONICS LTD.
USER MANUAL
MODEL:
920
70V/100V Power Amplifier
P/N: 2900-300308 Rev 2

920 –Contents
i
Contents
1Introduction 1
2Getting Started 2
2.1 Achieving the Best Performance 2
2.2 Safety Instructions 2
2.3 Recycling Kramer Products 3
3Overview 4
4Defining the 920 Power Amplifier 5
5Connecting the 920 7
5.1 Connecting the 920 7
5.2 Connecting Speakers 8
5.3 Connecting a Microphone 9
6Technical Specifications 10
Figures
Figure 1: 920 Power Amplifier Front Panel 5
Figure 2: 920 Power Amplifier Rear Panel 6
Figure 3: Connecting the 920 Power Amplifier 7
Figure 4: Connecting One or Multiple Speakers to the 920 (100V) 8
Figure 5: Connecting One or Multiple Speakers to the 920 (70V) 9
Figure 6: Connecting a microphone 9

920 - 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; GROUP 12: Digital Signage; and GROUP 13: Audio,
and GROUP 14: Collaboration.
Congratulations on purchasing your Kramer 920 Power Amplifier, which is ideal for
the following typical applications:
Boardrooms
Classrooms
Hospitality
Transportation
Retail
Entertainment
Houses of worship

2
920 - 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
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 920 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.
2.2 Safety Instructions
Caution:
There are no operator serviceable parts inside the unit
Warning:
Use only the power cord that is supplied with the unit
Warning:
Do not open the unit. High voltages can cause
electrical shock! Servicing by qualified personnel only
Warning:
Disconnect the power and unplug the unit from the wall
before installing
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!
!

920 - Getting Started
3
2.3 Recycling Kramer Products
The Waste Electrical and Electronic Equipment (WEEE) Directive 2002/96/EC
aims to reduce the amount of WEEE sent for disposal to landfill or incineration by
requiring it to be collected and recycled. To comply with the WEEE Directive,
Kramer Electronics has made arrangements with the European Advanced
Recycling Network (EARN) and will cover any costs of treatment, recycling and
recovery of waste Kramer Electronics branded equipment on arrival at the EARN
facility. For details of Kramer’s recycling arrangements in your particular country
go to our recycling pages at http://www.kramerelectronics.com/support/recycling/.

4
920 - Overview
3 Overview
The Kramer 920 is a high−performance audio power amplifier for balanced,
unbalanced and microphone signals, that can output 200W of audio into 70V or
100V speaker systems.
The 920 Power Amplifier features:
70V or 100V amplification
Balanced, unbalanced and microphone inputs
Input level sensitivity adjustment for line and microphone inputs
Optional microphone 48V phantom power
Optional high-pass filter
1U rack-mount enclosure

920 –Defining the 920 Power Amplifier
5
4 Defining the 920 Power Amplifier
Figure 1 defines the 920 Power Amplifier.
Figure 1: 920 Power Amplifier Front Panel
#
Feature
Function
1
STATUS LED
Lights green when the device is active.
Lights orange when the device is in standby mode.
Lights red when the device is in protection mode
2
SIGNAL LED
Lights green when the input signal is present.
Lights yellow when the signal is clipping
3
MIC LED
Lights green when the microphone input signal is present

Figure 2: 920 Power Amplifier Rear Panel
#
Feature
Function
1
LINE INPUT
5-pin Terminal Block
Connect to the balanced stereo source
2
BAL/ RCA Selector
Selects the balanced or unbalanced (RCA) input selector
3
RCA Connectors
Connect to the unbalanced stereo source
4
LEVEL Trimmer
Adjusts the line-level input
5
MIC INPUT
3-pin Terminal Block
Connect to the microphone
6
LEVEL Trimmer
Adjusts the microphone input level
7
PHANTOM (48V) Switch
Phantom power on/off switch
8
MIC Switch
Microphone input on/off switch
9
SPEAKER OUT
3-pin Terminal Connector
70V or 100V output to speakers (see Section 5.2)
10
HIGH-PASS FILTER Switch
High-pass filter on/off selector
11
Mains Power Unit
Connect to the mains power
Mains Fuse for protecting the 920
Switch for turning the device on and off
6
920 –Defining the 920 Power Amplifier

920 - Connecting the 920
7
5 Connecting the 920
This chapter comprises the following sections:
Connecting the 920 (see Section 5.1)
Connecting speakers (see Section 5.2)
Connecting a microphone (see Section 5.3)
5.1 Connecting the 920
Always switch off the power to each device before connecting it to your
920. After connecting your 920, connect its power and then switch on
the power to each device.
Figure 3: Connecting the 920 Power Amplifier
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8
920 - Connecting the 920
To connect the 920 as illustrated in the example in Figure 3:
1. Connect a balanced, stereo audio source, (for example, a multimedia player)
to the 5-pin Line Input terminal block and an unbalanced stereo audio source
to the Line Input RCA connectors.
2. Select the BAL-RCA switch accordingly.
3. Connect a microphone to the 3-pin Mic Input terminal block.
4. Connect the speaker(s) to the Speaker Out 3-pin terminal block, (see
Section 5.2).
5. Connect the unit to the mains supply using the supplied power cord.
5.2 Connecting Speakers
You can connect one or more 70V or 100V speakers to the 920. When connecting
more than one speaker they must be connected in parallel as shown in Figure 4
(100V speakers) and Figure 5 (70V speakers).
Figure 4: Connecting One or Multiple Speakers to the 920 (100V)

920 - Connecting the 920
9
Figure 5: Connecting One or Multiple Speakers to the 920 (70V)
5.3 Connecting a Microphone
The 920 can provide phantom power (48V) to a microphone.
Figure 6: Connecting a microphone

10
920 - Technical Specifications
6 Technical Specifications
INPUT:
1 Balanced stereo +4dBu/10kΩ on a 5-pin removable terminal
block
1 Unbalanced stereo on 2 RCA connectors
OUTPUT:
1 speaker 70/100V output on a 3-pin removable large terminal
block
INPUT SENSITIVITY:
0.3V to 1.23V –10dBu to 4 dBu
OUTPUT POWER:
200W
AMPLIFIER TYPE:
Class D
MAXIMUM VOLTAGE
GAIN:
+26dB
BANDWIDTH (-3dB):
20Hz to 20kHz
S/N RATIO:
–75dB @14dBu amplification (0.039%)
CONTROLS:
Screw trimmer for line and mic input sensitivity
HIGH PASS FILTER:
When on:
Frequencies below 120Hz are attenuated by 12dB per octave,
–12dB @120Hz
–24dB @60Hz
–36dB @30Hz
INPUT SATURATION:
Maximum input level is 3.9V pp @ –48dB
AUDIO THD + NOISE:
70v main output: –71dB @ 7.8 dBu amplification
100v main output: –72 db @ 8.3 dBu amplification
AUDIO 2nd
HARMONIC:
0.08% for 70v/100v output
POWER SOURCE:
100240V AC, 50/60Hz, 480VA @220V; 330VA @110V
DIMENSIONS:
19” x 7.25” x 1U (W, D, H) rack-mountable
WEIGHT:
1.7kg (3.75lbs) approx.
INCLUDED
ACCESSORIES:
Power cord, rack ears
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]
SAFETY WARNING
Disconnect the unit from the power
supply before opening and servicing
P/N:
2900-300308
Rev:
2
!