Key Digital KD-AMP220 User manual

2 Channel 20 Watt Per Channel,
Compact Digital Audio Amplifier
KD-AMP220
Operating Instructions
The Experts in Digital Video Technology and Solutions™

4
Always follow the instructions provided in this Operating Manual.
Table of Contents
Introduction ................................................................ 1
Quick Setup Guide .......................................................... 2
Application Examples ........................................................ 3
Connections, Buttons and LEDs ................................................ 4
Speaker Wiring ............................................................. 7
IR Remote Control........................................................... 8
RS-232 Control ............................................................. 8
Specifications ............................................................. 12
Important Product Warnings & Safety Instructions: ................................. 14
FCC Statement ............................................................ 14
How to Contact Key Digital
®
.................................................. 15
Warranty Information ........................................................ 15

1
Introduction
The KD-AMP220 is a 2x20 watt Class-D amplifier with 8 Ωspeaker output ideal for
installation in presentation spaces. Input connections accommodate microphone, line level
balanced/unbalanced, and line level 3.5mm stereo analog audio inputs. The output is a mix
of audio from the microphone input and the selected audio input. Microphone and output
volume levels may be variably controlled via IR, RS-232, or the front panel, and speaker level
output may be set to bridge, stereo, or mono mode.
Key Features
›Class D Amplification: 40-Watt @ 8ohm / 20-Watt @ 4ohm
›Mixing: Output is a mix of microphone and the selected audio input
›Signal Processing:
»Variable volume level set for each input
»Variable volume, bass, and treble for output
›Inputs: Microphone (3-pin balanced, condenser/dynamic), 6-pin balanced stereo, 3.5mm stereo
›Phantom Power: 48V phantom power for integration with condenser microphones
›Outputs: Pre-amp line level (6-pin balanced), speaker level
›Speaker Level Output: Bridge, stereo, or mono modes selectable
›Noise gate: For consistent audio levels, prevention of ambient noise
›Control: Front panel, RS-232, IR with external IR Sensor (included)
›Compact Size: 4.84”(W) x 3.42”(D) x 1.3”(H)
Accessories
›Operating Instructions & Warranty card
›2 x L-type mounting ears
›IR Remote Control
›2 x 3-pin, 1 x 4-pin, 2 x 6-pin Phoenix Connectors
›Power Supply: 24V/2.71A (65W), screw-in type
›IR Sensor

2
Quick Setup Guide
1. Begin with the KD-AMP220 unit and all input/output devices turned off
and power cables removed.
2. Connect audio output of source devices to the desired input of KD-AMP220
using high-quality audio cables.
3. Connect a microphone to the microphone input connector.
4. Set 48V phantom power mode switch as needed:
»a) ON for Condenser microphones
»b) OFF for Dynamic microphones
5. Adjust the speaker output mode selector based on the desired output mode
of the KD-AMP220.
»a) STEREO – Stereo audio signals will maintain stereo audio on the outputs;
20 watts per output.
»b) MONO – Stereo audio signals will be summed to dual mono signals on the outputs;
20 watts per output.
»c) BRIDGE – Stereo audio signals will be summed to a single, high output audio output;
40 watts total output.
6. Connect speakers in accordance with above desired output mode.
Use high quality speaker wire. See Speaker Wiring section for more information
7. For IR control, plug the IR receiver into the IR Sensor port. IR receiver should be
mounted in line-of-sight location.
8. For RS-232 control, connect the master controller / control processor / control PC
to the RS-232 port.
9. Connect power to the KD-AMP220.
10. Connect power to input and output devices. Power on attached audio devices.

3
Application Examples
Basic
Advanced
Podium Laptop
Laptop
Ceiling Speakers
Display
Podium
Mic
VGA Laptop
VGA L/R
HDMI
HDMI HDMI
HDMI
L/R
L/R
KD-MLV4x2Pro
Master Controller
IR/RS-232
RS-232
KD-MC1000
KD-X222PO
KD-AMP220
KD-AMP220
CAT5e/6
Video Conferencing
Ceiling Speakers
Camera
Mic
Apple TV
Music Streamer
Podium Laptop
Laptop
Ceiling Speakers
Display
Podium
Mic
VGA Laptop
VGA L/R
HDMI
HDMI HDMI
HDMI
L/R
L/R
KD-MLV4x2Pro
Master Controller
IR/RS-232
RS-232
KD-MC1000
KD-X222PO
KD-AMP220
KD-AMP220
CAT5e/6
Video Conferencing
Ceiling Speakers
Camera
Mic
Apple TV
Music Streamer

4
Connections, Buttons and LEDs
Rear Panel
1 2 3 4 5 6 7 8 9 10
Input Connections and Selector
›1. Microphone Input and 48V Phantom Power Mode Switch
»a. Pin 1: +
»b. Pin 2: Ground
»c. Pin 3: -
›2. Phantom (48V) slide switch
»a. ON: Condenser microphones
»b. OFF: Dynamic microphones
›3. Balanced/Unbalanced Analog Input 1
»a. Pin 1: Left +
»b. Pin 2: Left Ground
»c. Pin 3: Left -
»d. Pin 4: Right +
»e. Pin 5: Right Ground
»f. Pin 6: Right -
›4. L/R Analog 3.5mm stereo Input 2
»a. Tip: Left
»b. Ring: Right
»c. Sleeve: Ground
Output Connections and Selector
›5. Balanced/Unbalanced Analog Audio Output
»a. Pin 1: Left +
»b. Pin 2: Left Ground
»c. Pin 3: Left -
»d. Pin 4: Right +
»e. Pin 5: Right Ground
»f. Pin 6: Right -

5
›6. Speaker Output
Speaker Mode Pin 1 Pin 2 Pin 3 Pin 4
STEREO Left Channel+ Left Channel- Right Channel+ Right Channel-
MONO Mono+ Mono- Mono+ Mono-
BRIDGE Mono+ N/C N/C Mono-
›7. Speaker Output Mode Selector
»a. STEREO: 2 channels 20W@4ohm speakers
»b. MONO: 2 x mono 20W@4ohm speakers (stereo to mono conversion)
»c. BRIDGE: Single 40W@8ohm speaker (stereo to mono conversion)
Unit Control & Power
›8. IR Sensor Input
»a. Tip: IR Sensor (5V) Power
»b. Ring: IR Signal
»c. Sleeve: Ground
›9. RS-232
»a. Pin 1: TxD
»b. Pin 2: Ground
»c. Pin 3: RxD
›10. 24V DC Power Input
Front Panel
1 2 3 4 5
Input Connections and Selector
›1. Input Source select button and LEDs
›2. Control Button and LEDs
»a. Used to select Volume or EQ control of Mic or Line inputs
»i. Mic for volume control of MIC input
»ii. Line for volume control of LINE (inputs 1 or 2)
»iii. Bass for bass level control of LINE (inputs 1 or 2)
»iv. Treble for treble level control of LINE (inputs 1 or 2)

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›3. Volume Control Knob
»a. Controls level of Mic, Line, Bass, and Treble
»i. Bass and Treble settings apply only to Line level input
»b. Push to mute/un-mute respective control selection
»i. Mutes/un-mutes Mic input, if Mic is selected
»ii. Mutes/un-mutes Line input, if Line is selected
»iii. Mutes/un-mutes both Mic and Line inputs, if Bass or Treble are selected
»Note: Volume adjustments do not affect muting status. If volume is adjusted to a muted
source, it will remain muted.
›4. MUTE LED
»a. Illuminated if selected control position is muted/un-muted
›5. USB Service port
»a. Firmware update should only be applied if advised by Key Digital’s Technical Support
team.
›Factory Default via front panel: To factory default unit, press & hold Input + Control buttons
simultaneously for 10 seconds

7
Speaker Wiring
L/R Stereo
4ΩLoad with 4ΩSpeakers:
L/R Stereo with Parallel Speakers
4ΩLoad with 10W 8ΩSpeakers:
Bridged Audio Option
8ΩLoad with 8ΩSpeakers:

8
IR Remote Control
IR Control must be achieved via included IR sensor only.
There is no built-in IR sensor
›INPUT SEL: Direct selection of input 1 or input 2
›MUTE: Direct muting of MIC or LINE inputs. The SPEAKER
button unmutes all sources
›VOLUME CONTROL: Direct volume and level controls for
Mic, Line, Bass, and Treble.
›Note: IR Control must be achieved via included IR sensor
only. There is no built-in IR sensor.
RS-232 Control
KD-AMP220 gives access to all software functions when used controlled by RS-232
›
RS-232 cable pinout
Master Controller KD-AMP220
Tx Rx
Rx Tx
Ground Ground
Baud Rate = 9600 bits per second
›Data Bits = 8
›Stop Bits = 1
›Parity = None
›Flow Control = None
›Carriage Return: Required
›Line Feed: Required
›Commands are not case-sensitive.
Spaces shown below may be excluded.
›Carriage return and line feed is required at the end of each string.
Input Switching
Description Command Command Example and Response
Switch to Audio Input1 SPO01SA01 SPO01SA01
Output Audio switch to Input 01
Switch to Audio Input2 SPO01SA02 SPO01SA02
Output Audio switch to Input 02
Switch to Audio Input1
*Redundant Command SPO01SI01 SPO01SA01
Output Audio switch to Input 01
Switch to Audio Input2
*Redundant Command SPO01SI02 SPO01SA02
Output Audio switch to Input 02

9
Volume and EQ Settings
Description Command Command Example and Response
Turn Up the Volume of
MIC Audio SPI01AVU
SPI01AVU
Volume of MIC Audio [51] turn Up
Note: [xx] = Level 00 - 60
Turn Down the Volume
of MIC Audio SPI01AVD
SPI01AVD
Volume of MIC Audio [51] turn Down
Note: [xx] = Level 00 – 60
Turn Up the Volume of
Line Audio SPO01AVU
SPO01AVU
Volume of Line Audio [51] turn Up
Note: [xx] = Level 00 – 60
Turn Down the Volume
of Line Audio SPO01AVD
SPO01AVD
Volume of Line Audio [51] turn Down
Note: [xx] = Level 00 - 60
Turn Up the Bass Level
of Line Audio SPO01ALU
SPO01ALU
Bass Level of Line Audio [04] turn Up
Note: [xx] = Level 00 – 08
Turn Down the Bass
Level of Line Audio SPO01ALD
SPO01ALD
Bass Level of Line Audio [04] turn Down
Note: [xx] = Level 00 – 08
Turn Up the Treble
Level of Line Audio SPO01AHU
SPO01AHU
Treble Level of Line Audio [04] turn Up
Note: [xx] = Level 00 – 08
Turn Down the Treble
Level of Line Audio" SPO01AHD
SPO01AHD
Treble Level of Line Audio [04] turn Down
Note: [xx] = Level 00 – 08
Set the Volume of MIC
Audio to xx[ xx =
00~60 ]
SPI01AVxx
SPO01AV51
Volume of MIC Audio set to 51
Note: [xx] = Level 00 – 60
Set the Volume of Line
Audio to xx[ xx =
00~60 ]
SPO01AVxx
SPO01AV51
Volume of Line Audio set to 51
Note: [xx] = Level 00 – 60
Set the Bass Level of
Line Audio to xx[ xx =
00~08 ]
SPO01ALxx
SPO01AL04
Bass Level of Line Audio set to 04
Note: [xx] = Level 00 – 08
Set the Treble Level of
Line Audio to xx[ xx =
00~08 ]
SPO01AHxx
SPO01AH04
Volume of Line Audio set to 04
Note: [xx] = Level 00 – 08

10
Muting
Description Command Command Example and Response
Mute both MIC and
LINE Audio SPO01AE SPO01AE
Output Audio Mute Enabled
Unmute both MIC and
Line Audio SPO01AD SPO01AD
Output Audio Mute Disabled
Mute MIC Audio Only SPI01AE SPI01AE
MIC Audio Mute Enabled
Mute Line Audio Only SPI02AE SPI02AE
Line Audio Mute Enabled
Unmute MIC Audio
Only SPI01AD SPI01AD
MIC Audio Mute Disabled
Unmute Line Audio
Only SPI02AD SPI02AD
Line Audio Mute Disabled
Set Noise Gate ON SPO01NGON SPO01NGON
Noise Gate is ON
Set Noise Gate OFF SPO01NGOFF SPO01NGOFF
Noise Gate is OFF
System Query
Description Command Response
Print Help Message HSee below
Print Status Message STA See below
Factory Reset
Description Command Command Example and Response
Set Factory Default SPCDF
SPCDF
Factory Default is Done
Note: Default settings
»Line Source: Input 1
»Mic Volume: 45
»Mic Mute: OFF
»Line Volume: 45
»Line Mute: OFF
»Bass: 4
»Treble: 4
»Noise Gate: ON

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The Help command “H” returns a full list of all possible RS-232 commands:
KD-AMP220>H
---------------------------------------------------
-- Key Digital Systems HELP --
---------------------------------------------------
-- KD-AMP220 F/W Version : V1.0.0 --
-- SPO01SA01 : Switch to Audio Input1 --
-- SPO01SA02 : Switch to Audio Input2 --
-- SPI01AE : Mute MIC Audio Input --
-- SPI01AD : Unmute MIC Audio Input --
-- SPI02AE : Mute LINE Audio Input --
-- SPI02AD : Unmute LINE Audio Input --
-- SPO01AE : Mute Audio Output --
-- SPO01AD : Unmute Audio Output --
-- SPO01NGON : Set Noise Gate ON --
-- SPO01NGOFF : Set Noise Gate OFF --
-- --
-- SPI01AVU : Turn Up the Volume of MIC --
-- SPI01AVD : Turn Down the Volume of MIC --
-- SPO01AVU : Turn Up the Volume of LINE --
-- SPO01AVD : Turn Down the Volum of LINE --
-- SPO01ALU : Turn Up the Bass Level of LINE --
-- SPO01ALD : Turn Down the Bass Level of LINE --
-- SPO01AHU : Turn Up the Treble Level of LINE --
-- SPO01AHD : Turn Down the Treble Level of LINE --
-- xx = [00~60], yy = [00~08] --
-- SPI01AVxx : Set the Volume of MIC to xx --
-- SPO01AVxx : Set the Volume of LINE to xx --
-- SPO01ALyy : Set the Bass Level of LINE to yy --
-- SPO01AHyy : Set the Treble Level of LINE to yy--
-- --
-- --
-- SPCDF : Set Factory Default --
-- H : Show Help --
-- STA : Show Status --
---------------------------------------------------
The Status command “STA” returns unit status for all settings
KD-AMP220>sta
---------------------------------------------------
-- Key Digital Systems STATUS --
---------------------------------------------------
-- KD-AMP220 F/W Version : V1.0.0 --
-- Line Audio Source : Input 1 --
-- MIC Audio : Volume = 45, Mute = OFF --
-- Line Audio : Volume = 45, Mute = OFF --
-- Bass = 4, Treble = 4 --
-- Noise Gate : ON --
--------------------------------------------------

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Specifications
I/O Connections
Analog Inputs One (1) 6-pin Phoenix Connector;
One (1) 3.5mm TRS Connector
Microphone Input One (1) 3-pin Phoenix Connector
Control (Front Panel) Push Button, Rotary Knob
Control (Rear Panel) RS-232 via One (1) 3-pin Phoenix Connector;
IR via One (1) 3.5mm TRS Connector
Microphone 48V Phantom
Power Mode Switch
One (1) 2-Position Slide Switch
Output Signal Format Selector One (1) 3-Position Slide Switch
Balanced/Unbalanced Analog
Audio Output
One (1) 6-pin Phoenix Connector
Speaker Output One (1) 4-pin/5 mm Phoenix Connector
24V DC Power One (1) Barrel (5.5 mm OD, 2.1 mm ID)
Audio Performance
Input Impedance >10k Ω
Output Impedance 50 ΩAnalog Output; 4/8 ΩSpeaker Output
Maximum Rated Power Output 40 Watts
Frequency Response 120 Hz to 20 kHz
Common Mode Rejection Ratio
(CMRR)
>70 dB at 20 Hz to 20 kHz
Signal to Noise Ratio (SNR) 80 dB (Max)
Total Harmonic Distortion +
Noise (THD+N)
1% at 1 kHz; 0.3% at 20 kHz at Nominal Level
Voltage Gain 32 dB

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Chassis and Environmental
Enclosure Painted Aluminum
Dimensions (W x H x D) 8.661” x 1.299” x 4.094” (LxDxH)
Net Weight 1.153 Lb
Operating Temperature +32° to +104° F (0° to +40° C)
Operating Humidity 20% to 90%, Non-condensing
Storage Temperature +14° to +140° F (-10° to +60° C)
Storage Humidity 20% to 90%, Non-condensing
Power, ESD, and Regulatory
Minimum Power Consumption 5 watts
Maximum Power Consumption 45 watts
Power Supply Input Voltage 100-240v AC at 50/60 Hz at 0.5 A
Power Supply Output Rating 24V DC at 2.71 A
ESD Protection 15kV
Device Regulatory CE, FCC
Power Supply Regulatory CE, FCC

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Important Product Warnings:
1. Connect all cables before providing power to the unit.
2. Test for proper operation before securing unit behind walls or in hard to access spaces.
3. If installing the unit into wall or mounting bracket into sheet-rock, provide proper screw support
with bolts or sheet-rock anchors.
Safety Instructions:
Please be sure to follow these instructions for safe operation of your unit.
1. Read and follow all instructions.
2. Heed all warnings.
3. Do not use this device near water.
4. Clean only with dry cloth.
5. Install in accordance with the manufacturer’s instructions.
6. Do not install near any heat sources such as radiators, heat registers, stoves, or other
apparatus (including amplifiers) that produce heat.
7. Only use attachments/accessories specified by the manufacturer.
8. Refer all servicing to qualified service personnel. Servicing is required when the device has
been damaged in any way including:
»Damage to the power supply or power plug
»Exposure to rain or moisture
Power Supply Use:
You MUST use the Power Supply provided with your unit or you VOID the
Key Digital®Warranty and risk damage to your unit and associated equipment.
FCC Statement
This equipment generates, uses and can radiate radio frequency energy and, if not installed
and used in accordance with the instructions, may cause harmful interference to radio
communications. It has been tested and found to comply with the limits for a Class B digital
device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a commercial installation.
Operation of this equipment in a residential area is likely to cause interference, in which case the
user at their own expense will be required to take whatever measures may be necessary to correct
the interference.
Any changes or modifications not expressly approved by the
manufacture would void the user’s authority to operate the equipment.

15
How to Contact Key Digital
®
System Design Group (SDG)
For system design questions please contact us at:
›Phone: [phone]
›E-mail: [email protected]
Customer Support
For customer support questions please contact us at:
›Phone: [phone]
›E-mail: [email protected]
Technical Support
For technical questions about using Key Digital
®
products, please contact us at:
›Phone: [phone]
›E-mail: [email protected]
Repairs and Warranty Service
Should your product require warranty service or repair, please obtain a
Key Digital
®
Return Material Authorization (RMA) number by contacting us at:
›Phone: [phone]
›E-mail: [email protected]
Feedback
Please email any comments/questions about the manual to:
›E-mail: [email protected]
Warranty Information
All Key Digital
®
products are built to high manufacturing standards and should provide years of
trouble-free operation. They are backed by a Key Digital Limited 3 Year Product Warranty Policy.
http://www.keydigital.com/warranty.htm

16

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Key Digital®, led by digital video pioneer Mike Tsinberg,
develops and manufactures high quality, cutting-edge
technology solutions for virtually all applications where
high-end video and control are important. Key Digital®
is at the forefront of the video industry for Home Theater
Retailers, Custom Installers, System Integrators,
Broadcasters, Manufacturers, and Consumers.
Key Digital®Systems :: 521 East 3rd Street :: Mount Vernon, NY 10553
Phone : [phone] Fax : [phone] Web : www.keydigital.com
Rev 0 – Aug 2017