adastra A2 Rackmount Stereo Amplifier with Media Player User Manual
- June 4, 2024
- Adastra
Table of Contents
A2 Rackmount Stereo Amplifier with Media Player
Item ref: 953.402UK
User Manual
A2 Rackmount Stereo Amplifier with Media Player
Version 1.0
Caution: Please read this manual carefully before operating damage caused
by misuse is not covered by the warranty
Introduction
Thank you for choosing the Adastra A2 rackmount stereo amplifier to power your
public address system. This amplifier is designed to offer high-quality,
dependable service for mobile and installed systems. Please read this manual
fully and follow the instructions to achieve the best results with your new
purchase and to avoid damage through misuse.
SAFETY SYMBOL AND MESSAGE CONVENTIONS
CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN
AVIS RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR
This symbol indicates that dangerous voltage constituting a risk of electric
shock is present within this unit
This symbol indicates that there are important operating and maintenance
instructions in the literature accompanying this unit.
SAFETY NOTICE
- Prior to use, read through this manual
- Keep the manual in good condition
- Pay attention to safety warnings
- Observe all operating requirements
- Do not use the device near water or wet areas
- For cleaning, only use a lint-free, dry cloth
- Install according to the specifications
- Place away from heat sources or heating appliances
- Use the mains lead provided and avoid damage to cable or connectors
- Unplug power from mains during stormy weather or if unused for long periods
- In case of malfunction, water ingress, or other damage, consult qualified service personnel
- Do not place in damp areas or near liquids or moisture. Do not spill liquids on the housing
- Please pay attention to warning symbols during transit and placement
- Terminals marked with the symbol
**+**are HAZARDOUS LIVE and should only be connected by qualified personnel - Ensure that the apparatus is connected to a mains socket with a protective EARTH connection
- Ensure correct operation of the mains switch
Warning
To prevent the risk of fire or electric shock, do not expose any components to
rain or moisture.
If liquids are spilled on the casing, stop using it immediately, allow the
unit to dry out, and have checked by qualified personnel before further use.
Avoid impact, extreme pressure, or heavy vibration to the case
No user-serviceable parts inside – Do not open the case – refer all servicing
to qualified service personnel.
Safety
- Check for correct mains voltage and condition of IEC lead before connecting to a power outlet
- It is recommended to use a speaker wire with a minimum current rating of 6A per output.
- Do not allow any foreign objects to enter the case or through the ventilation grilles
Placement
- Keep out of direct sunlight and away from heat sources
- Keep away from damp or dusty environments
- For rack-mounting, use the rack ears provided and ensure adequate support for the weight of the amplifier
- Ensure adequate airflow and do not cover cooling vents
- Ensure adequate access to controls and connections
Cleaning
- Use a soft cloth with a neutral detergent to clean the casing as required
- Use a vacuum cleaner to clear ventilation grilles of any dust or debris build-ups
- Do not use strong solvents for cleaning the unit
Front panel
- Power on/off switch
- SD card slot
- Media player display
- 3.5mm stereo Aux input
- Aux input volume control
- Media player volume control
- Line 1 input volume control
- Line 2 input volume control
- Stereo input selector
- Bass EQ control
- Treble EQ control
- Channel 1 output level control
- Channel 2 output level control
- USB port
- Media player control panel
- Mic 1 input 6.3mm jack
- Mic 2 input 6.3mm jack
- Mic 1 volume control
- Mic 2 volume control
- Talkover on/off button
- Output Signal & Clip indicators Rear panel
- Ventilation grille (do not obstruct airflow) 23. FM antenna connection (F type)
- Line 2 input (L+R RCA)
- Line 1 input (L+R 6.3mm jack)
- Line 1 input (L+R RCA)
- Line output
- Channel 1 speaker output +/- 4mm binding posts
- Channel 2 speaker output +/- 4mm binding posts
- IEC mains inlet & fuse holder
Speaker connections
The A2 has 2 speaker output channels (Ch1 + Ch2) which can be used for Left and Right stereo output. For each output, connect “–” to the “–” speaker terminal(s) and “+” to the “+” speaker terminal(s) Connect speakers with a combined impedance of no lower than 4Ω to each output channel.
- If the speakers being connected are 4Ω, then connect only 1 speaker to each channel.
- If the speakers are 8Ω, you can connect up to 2 speakers in parallel to each channel.
- If the speakers are 16Ω, you can connect up to 4 speakers in parallel to each channel.
Some example wiring diagrams are shown opposite with speakers connected in
parallel.
The impedance of the load measured in “Ohms” (Ω) will also determine the power
output.
The amplifier delivers its maximum power output at the minimum impedance
rating (4Ω). Higher impedances result in a lower output.
The combined load on each output shares the power from the amplifier. If the
amplifier is delivering 200W to 2 speakers connected in parallel with the same
impedance, they must each be capable of handling 100W.
Input connections
The A2 has 2 microphone inputs and 4 selectable stereo sources (one of which
is the internal media player)
Connect wired microphone(s) to the Mic 1 and/or Mic 2 jack inputs (6.3mm) on
the front panel (16, 17)
The volume level of these is controlled by the Mic 1 and Mic 2 volume controls
(18, 19)
A smart phone, tablet or mp3 player can be connected to the Aux jack (3.5mm)
on the front panel (4)
The volume level of this stereo input is controlled by the Aux volume control
(5)
To hear this input through the speakers, “AUX” must be selected on the input
selector (9)
On the rear panel, there are 2 further stereo line inputs for connecting
CD/DVD players, DVB/DAB tuners etc. Line 1 input has a choice of Left + Right
6.3mm jack (25)
or RCA inputs (26)
The volume level of this input is controlled by the Line 1 volume control (7)
To hear this input through the speakers, “LINE 1” must be selected on the
input selector (9)
Line 2 has Left + Right RCA inputs (27)
The volume level of this input is controlled by the Line 2 volume control (8)
To hear this input through the speakers, “LINE 2” must be selected on the
input selector (9)
The mix of mic1+2 and selected line input can be fed onto further equipment
via the RCA Line output (27)
For good reception of FM radio stations (if needed) in the media player, the
A2 has an “F” connector on the rear panel (23) which can be connected to an
external FM antenna (aerial)
Connect the IEC power inlet (30) to the 230Vac mains supply, using the IEC
lead provided.
Operation
When all connections to the amplifier are made, turn all rotary controls down
and switch on the power (1) and the media player display will illuminate.
Turn Bass and Treble controls (10, 11) to the 12 o’clock position (pointing
straight up) and turn the Ch1 and Ch2 rotary controls (12, 13) up part-way for
testing.
If a microphone is connected to one of the mic inputs (16,17) gradually
increase the volume control for that channel (18,19) and speak into the mic
until it is heard through the speakers.
Alternatively, play a signal into one of the aux or line inputs (4, 24, 25,
26) and ensure it is selected on the input selector (9), and turn up its
volume control (5, 7, 8) until the signal is heard through the speakers.
The same test applies to the internal media player (see the section below) by
playing a track or radio station. Select “MEDIA PLAYER” on the input selector
and gradually increase the media player volume (6)
Turn up the Ch1 and Ch2 volume controls to the maximum required volume level
and reduces the channel volume control if necessary.
The output of each speaker channel is represented on the SIG and CLIP LEDs
(21) and care should be taken that the red CLIP LED is only lit momentarily
during use. Anything longer than a short flash of this LED may be indicating
distortion or clipping of the output signal and the output channel volume
control should be turned down.
Any microphones connected should not be able to “hear” the speakers, which can
cause feedback (squealing or howling) and should not be pointed toward the
speakers. If this still happens, turn down the volume for that microphone and
adjust the Bass and/or Treble EQ controls to reduce the feedback
If the TALKOVER feature (20) is switched on, speaking into the microphone will
“override” any audio playback from the selected stereo Aux, Line or Media
input, which will be reduced in volume temporarily. This allows voice
announcements to be heard without interference from the line inputs or media
player.
In addition to input and output volume controls, there are Bass and Treble EQ
controls (10, 11) to adjust the tone of the overall output. At the 12 o’clock
position, these controls apply no effect to the signal (no boost or cut).
Moving the Bass control clockwise boosts the low frequencies in the audio,
whilst moving it anticlockwise will cut these low frequencies.
Likewise, moving the Treble control clockwise boosts the high frequencies in
the audio, whilst moving it anticlockwise will cut these high frequencies.
Adjust these EQ controls to suit the type of audio signal or compensate for
the room acoustics.
To avoid loud pops through the speakers, turn down the Ch1 & Ch2 volume
controls before powering down.
Media player
The A2 amplifier is equipped with a multi-functional media player for
playback of audio files from USB or SD media, FM radio stations or Bluetooth
connection. Front panel controls are as described below.
MODE
| Select between USB, SD, FM tuner & Bluetooth
---|---
REP
| Repeat mode – Random, One, Folder and All
| Previous track/FM station (hold for volume down)
| Play/Pause (Auto-tune in FM mode)
| Next track/FM station (hold for volume up)
EQ
| Select preset – Bass/Pop/Rock/Jazz/Classical/Normal
USB/SD media playback
Insert USB or SD media containing mp3 tracks and playback should begin
automatically.
The stored tracks should be in standard mp3 audio format. If playback does not
start, press MODE or
The display will initially show the tracking number and then an elapsed time
counter.
A USB or SD symbol will also be displayed to show which media is being used.
Ensure MEDIA PLAYER is selected on the output selector (9) and turn up the
MEDIA volume control (6)
Tracks may be navigated by pressing for the previous track and for the next
track. Press and hold to reduce the media player volume or press and hold to
increase the volume. Playback can be paused and resumed by pressing
Pressing REP sets the repeat mode: = random, = single track, = folder, =
all tracks
Pressing EQ sets the preset: = bass, = pop, = rock, = jazz, = classical, =
normal
FM Tuner
The FM tuner function operates in the same way as a standard FM radio and
benefits from the connection of
an FM antenna to the rear panel ‘F’ type connector.
Press the media player MODE button until the display shows a frequency (e.g.”
”)
If auto-tuning has already been performed, the display may show a channel
(e.g. “ ”)
If no channels are tuned in, press the button to begin auto-tuning, which
scans available stations and stores them as channels within the FM tuner.
Pressing again will abort the auto-tuning.
To step through pre-set stations, press the or buttons… etc.
Press and hold to reduce the FM radio volume or press and hold to increase the
volume.
Bluetooth
The Bluetooth function allows the connection of a smart phone or tablet to
the media player section for playback of stored files or streamed digital
audio. To enable this function, it will be necessary to pair the sending
device to the receiver as follows.
- Press the media player MODE button until the display flashes “ ”
- Open the Bluetooth settings menu on the smartphone or tablet (or another sending device)
- Scan for Bluetooth devices and look for “A series” in the list of available devices (ensure that the A2 is powered on, Bluetooth mode is selected and within reception range)
- Select “A series” and the sending device should confirm that it is connected as an audio device.
- Play audio from the sending device, ensuring that volume controls are not turned down/muted
- Select MEDIA PLAYER input (9) and turn up the MEDIA volume control (6) to the required level.
The , and buttons will operate in Bluetooth as remote playback controls.
Holding the or buttons will adjust the output volume of the player.
If the sending device goes out of range, the connection should automatically
resume when back in range. Likewise, if a different mode is selected, the
connection should resume when Bluetooth mode is re-selected. If Bluetooth is
disabled on the sending device or paired to a different receiver, it will be
necessary to reconnect the sending device to the A2 from step 2 above to re-
establish a Bluetooth link.
Media player remote control
In addition to front panel controls, the media player can be operated via
the supplied I.R. remote handset.
As supplied, the handset will have a plastic tab at the bottom to preserve
battery charge before the first usage. Remove this tab by pulling away from
the handset to engage the battery and activate the remote control. If this
needs to be replaced, the battery compartment can be slid out from the bottom
to reveal the cell. Replace the battery with a CR2025 button cell.
Point the top of the remote control towards the media player display and
operate in line of sight.
Some of the controls on the remote handset mirror those on the front panel and
are described below.
| Media player power on/standby button
---|---
| Repeat mode – select Random, One, Folder, or All tracks
MODE
| Select USB, SD, FM tuner, or Bluetooth mode
CH-/CH+
| Select an FM radio station
EQ
| Select preset EQ – Bass, Pop, Rock, Jazz, Classical or Normal
| Previous or Next track select
| Play / Pause track (auto-tune in FM tuner mode)
| Adjust media player volume down or up
0-9
| Direct track or channel access – key in the number
Specifications
| Power supply | 230Vac, 50Hz (IEC) |
|---|---|
| Power consumption max. | 280W |
| Fuse | F5A, 250V |
| Output power RMS @ 4 Ohms | 2 x 200W |
| Output power RMS @ 8 Ohms | 2 x 100W |
| Amplifier: Construction | Class D |
| Frequency response | 20Hz – 20kHz ±0.5dB |
| Microphone inputs | 2 x 6.3mm jack (mono) |
| Line inputs | Line 1: L+R (6.3mm jack/RCA), Line 2: L+R (RCA), Aux (3.5mm |
stereo)
Input sensitivity: line| 0.775Vrms
Input sensitivity: aux| 0.480Vrms
Input impedance| 20k Ohms (balanced), 10k Ohms (unbalanced)
Audio source| USB/SD mp3 playback, FM tuner, BT receiver
Input controls| Aux, Media, Linel, Line2, Mid, Mic2, Talkover
Line output| 2 x RCA
Speaker outputs| 4mm binding posts (2 channels)
Antenna connection| F type (FM tuner)
Output controls| Source select, Bass, Treble, Chl, Ch2
Dynamic range| 92dB
THD +N| <0.1%
Protection| Thermal, over-current, over-voltage, short-circuit
Dimensions| 482 x 240 x 88mm
Weight| 5.21kg
Troubleshooting
No power LED on the control panel| Ensure IEC lead is in good condition and
connected properly
---|---
Ensure the POWER switch is on and check the mains inlet fuse
The power light and output LEDs lighting but no output| Check speaker output
terminals are connected correctly
Check speakers are working (test on another amp if available)
Check memory device is connected properly (remove and re-insert)
Check file types — standard mp3 digital audio files required
Check memory device works on a PC or Mac for standard playback
Bluetooth cannot connect| Ensure that Bluetooth is enabled on sending the
device
Ensure that the sending device is within Bluetooth range (5-10m)
Check that the device is connecting to “A series”
No audio from Bluetooth device| Ensure that volume controls are not turned
down on sending the device
Check the volume and Play/Pause buttons on the media player
Output too loud or distorted| Reduce MIC, LINE-IN, USB/SD, and/or MASTER level
Ensure Iii-Z line level input(s) are not connected to a Mic input
Output too quiet or inaudible| Increase MIC, LINE IN, USB/SD, and/or MASTER
level
Check for the quiet recording of media files on the USB
Check VOX override is not unintentionally suppressing audio playback
Feedback from microphone| Face microphone away from speakers and monitors and
reduce the level
Amplifier overheating| Ensure cooling vents are clear from debris and dust
Ensure that the load impedance on any output channel is no less than 4Q
Disposal: The “Crossed Wheelie Bin” symbol on the product means that the product is classed as Electrical or Electronic equipment and should not be disposed of with other household or commercial waste at the end of its useful life. The goods must be disposed of according to your local council guidelines.
Errors and omissions excepted.
Copyright© 2018. AVSL Group Ltd.
953.402UK User Manual
www.avsl-adastra.com