A20-TX Digital Wireless Bodypack Transmitter
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Product Information
Specifications:
- Product Name: ASTRAL A20-TX Digital Wireless Bodypack
Transmitter - Key Features:
- Worldwide VHF and UHF tuning range from 169 MHz-1525 MHz
- More than 10 hours of battery runtime
- Eco-friendly operation from rechargeable Li-Ion batteries or
from standard AA batteries - Built-in battery charger via USB-C
- Full remote control of the A20-TX via A20-Remote companion app
and from the A20-SuperNexus, A20-Nexus, and A20-Nexus Go via
long-range NexLink - State-of-the-art 100% digital long-range modulation with three
modulation modes available - RF Power output from 2 mW to 40 mW
- Lemo input supports various audio connections
Product Usage Instructions:
Charging the Device:
1. Use the provided USB-C cable to connect the transmitter to a
power source for charging.
2. Allow the device to charge until the battery indicator shows
a full charge.
Connecting to an Astral Receiver:
1. Turn on both the A20-TX transmitter and the Astral
receiver.
2. Use the remote control app or NexLink feature for seamless
connection between devices.
Adjusting Modulation Modes:
1. Navigate to the Settings menu on the transmitter.
2. Select the desired modulation mode from the available
options: Standard, Long Range, or T&M.
Monitoring Battery Level:
1. Check the Power LED indicator on the front panel to monitor
battery level.
2. Refer to the LED color codes for battery status (Green =
Good, Orange = Medium, Red = Low).
Frequently Asked Questions (FAQ):
Q: Can the A20-TX be used with non-Astral receivers?
A: The A20-TX is designed for optimal performance with Astral
receivers, but it may work with other compatible digital
receivers.
Q: How do I update the firmware of the A20-TX?
A: Firmware updates can be done through the A20-Remote app or by
connecting the transmitter to a computer with the provided USB-C
cable.
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ASTRAL
A20-TX
Digital Wireless Bodypack Transmitter with GainForward, SpectraBand, and NexLink
User Guide v8.00
Table of Contents
Welcome to the A20-TX……………………………………………………………………………………………………………………………………………………3 SpectraBand …………………………………………………………………………………………………………………………………………………………………..4 NexLink Wireless Transmitter Control…………………………………………………………………………………………………………………………………4 GainForward …………………………………………………………………………………………………………………………………………………………………..4 Interface Description ………………………………………………………………………………………………………………………………………………………..5 Home Screen………………………………………………………………………………………………………………………………………………………………….9 Power ………………………………………………………………………………………………………………………………………………………………………….11 Identify (ID) …………………………………………………………………………………………………………………………………………………………………..12 Menus ………………………………………………………………………………………………………………………………………………………………………….13
RF ………………………………………………………………………………………………………………………………………………………………………..13 Pair ………………………………………………………………………………………………………………………………………………………………………13 Audio ……………………………………………………………………………………………………………………………………………………………………14 Record ………………………………………………………………………………………………………………………………………………………………….14 Privacy ………………………………………………………………………………………………………………………………………………………………….14 Settings …………………………………………………………………………………………………………………………………………………………………15 Tuning the A20-TX and Receiver……………………………………………………………………………………………………………………………………..17 Audio Levels – GainForward ……………………………………………………………………………………………………………………………………………18 Recording WAV Files……………………………………………………………………………………………………………………………………………………..18 Jamming Timecode………………………………………………………………………………………………………………………………………………………..19 File Transfer to a Computer …………………………………………………………………………………………………………………………………………….19 Updating Firmware…………………………………………………………………………………………………………………………………………………………19 A20-Remote………………………………………………………………………………………………………………………………………………………………….20 SD-Utility ………………………………………………………………………………………………………………………………………………………………………20 Accessories ………………………………………………………………………………………………………………………………………………………………….21 Included ………………………………………………………………………………………………………………………………………………………………..21 Optional ………………………………………………………………………………………………………………………………………………………………..21 Installing the Optional A20-TX Switch……………………………………………………………………………………………………………………………….22 Installing the Optional A-BOOM 2 …………………………………………………………………………………………………………………………………….23 Frequency Authorization …………………………………………………………………………………………………………………………………………………24 A20-TX Specifications…………………………………………………………………………………………………………………………………………………….25 Antenna Guide………………………………………………………………………………………………………………………………………………………………28 Servicing the A20-TX ……………………………………………………………………………………………………………………………………………………..29 Warranty ………………………………………………………………………………………………………………………………………………………………………29 Patents ………………………………………………………………………………………………………………………………………………………………………..30 Legal Notices ………………………………………………………………………………………………………………………………………………………………..30 Declaration of Conformity ……………………………………………………………………………………………………………………………………………….33
A20-TX User Guide
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Welcome to the A20-TX
Sound Devices A20-TX bodypack transmitter is compatible with more input sources than any other transmitter, adding incredible flexibility to any audio kit. Whether worn on the belt of talent, mounted on a boom pole on a film set, or used in many other applications, the combination of audio quality, battery life, and RF performance is second to none. Additionally, worldwide travel is possible with the A20-TX transmitter, because it can easily be set to transmit on the legal frequencies of any country.
The A20-TX incorporates state-of-the-art features, such as NexLink remote control, Long Range modulation, GainForward, SpectraBand, internal 32-bit float recording, and more, to produce the best sound quality possible. The A20-TX is compatible with Astral Receivers (A20-SuperNexus, A20-Nexus, A20-Nexus Go), A20-RX, and A10-RX digital receivers.
Key Features:
Worldwide VHF and UHF tuning range from 169 MHz-1525 MHz. More than 10 hours of battery runtime. Eco-friendly operation from rechargeable Li-Ion batteries or from standard AA batteries. Built-in battery charger via USB-C. Full remote control of the A20-TX via A20-Remote companion app and from the A20-SuperNexus, A20-Nexus and A20-
Nexus Go via long-range NexLink. State-of-the-art 100% digital long-range modulation delivers the longest transmission distance of any system on the
market. Three modulation modes available: Standard, Long Range, and T&M (Test and Measurement). RF Power output from 2 mW to 40 mW. Lemo input supports 2-wire or 3-wire mono lav, balanced mic, switchable 12, 48V phantom, balanced line-level, AES3,
AES42 (compatible with Schoeps SuperCMIT), and guitar (w/ optional A20-TX Smart Guitar Cable). GainForward Architecture no gain control to worry about on the A20-TX. Full 10 Hz – 20 kHz audio bandwidth. 8-Series, fully-balanced mic preamp built-in (140 dB dynamic range). Ultra-quiet lavalier mic preamp (134 dB dynamic range). Built-in 1 or 2-ch 32-bit float, 48 kHz recording to a removable micro SD card (not included). Ultra-stable timecode built-in, auto jammed via wireless NexLink. Sunlight readable e-Paper screen for control and display. Display persists with no batteries. USB-C for pairing with the Astral Receivers, file offload, charging, and timecode jamming. Bluetooth for remote control from A20-Remote iOS/Android App and for wireless pairing. Optional A20-TX Switch, a user-programmable, magnetically sensed, physically removable, bayonet-style switch.
Our friendly and knowledgeable support team, based in the USA and the UK, is here for all your questions and comments. Our job is to make your job easier.
Terminology used throughout this guide:
Astral Receiver refers to the A20-SuperNexus, A20-Nexus, and A20-Nexus Go multichannel receivers.
A20-TX User Guide
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SpectraBand
The A20-TX features SpectraBand, a technology that enables the A20-TX to tune over a super wide range of 169-1525 MHz. Tuning within this range varies by country. For instance:
In the USA, the available frequency ranges are:
The VHF band (specific frequencies within the 169-216 MHz range) The entire UHF TV band (470-608 MHz) The 600 MHz guard band (614-616 MHz) The 600 MHz duplex gap (653-663 MHz) The 900 MHz ISM band (902-928MHz) The 950 MHz STL band (941.5-960 MHz) The 1.5 GHz AFTRCC band (1435-1525 MHz), with an appropriate license.
In the UK, the available frequency ranges are:
The VHF band (specific frequencies within the 173-210 MHz range) The core UK UHF TV band (470-702 MHz) The 800 MHz duplex gap (823-832 MHz) The 800 MHz guard band (863-865 MHz) The DME bands (961-1015 MHz, 1045-1075 MHz, 1105-1154 MHz), with an appropriate license. The IMT band (1518-1525 MHz)
Please see https://www.sounddevices.com/available-frequencies/ for further detailed information on which frequency ranges are available for each country.
NexLink Wireless Transmitter Control
NexLink is a proprietary 2.4 GHz bidirectional wireless data link technology that allows multiple A20-TX transmitters to be controlled, monitored, and timecode synced from an A20-SuperNexus, A20-Nexus, or A20-Nexus Go digital receiver over long distances. NexLink is designed to offer robust and reliable control over distances far exceeding that of the wireless audio transmission, even in the presence of Wi-Fi, Bluetooth, and other 2.4 GHz interference. The A20-SuperNexus, A20-Nexus and A20-Nexus Go can pair with up to 64 NexLinked transmitters at a time.
GainForward
The A20-TX transmitter supports GainForward, a technology that eliminates the need to adjust audio gain at the wireless transmitter. Audio levels from the transmitter are controlled either directly at the mixer’s trim control or at the wireless receiver. If the source is too soft or too loud, adjust the transmitter’s audio level with a downstream mixer’s digital trim gain control. There is absolutely no noise penalty when the audio path remains 100% digital (i.e., A20 transmitter -> A20 receiver, A20 receiver digital audio output -> mixer digital audio input). Read more about GainForward at: https://www.sounddevices.com/gainforward-explained/
A20-TX User Guide
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Interface Description
Front and Side Panels, Battery Door Closed
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5
2 5
6
4
6
1: Power LED
Indicates power state. Can be turned off in the Settings>LEDs menu.
Green = Good battery level Orange = Medium battery level Red = Low battery Fast Flashing Red = Critically low battery. RF, audio, and recording are disabled. White = Displayed momentarily during battery insertion Blue = Displayed momentarily when pressing the power button to power up. Rapidly alternating red, green, blue = Transmitter being ID’d from A20-Nexus or the A20-Remote app.
2: Audio Signal and Timecode LED Audio/Timecode LED indicates audio activity and timecode status.
Green (variable intensity) = normal signal level. Solid Blue = muted Pulsing Blue = When the transmitter is powered on, timecode is syncing via NexLink. When powered off and timecode is
synced, pulsing occurs on the 00 frame. Timecode is held for 4 hours. Rapidly alternating red, green, blue = Transmitter being ID’d from A20-Nexus or the A20-Remote app.
3: ePaper Screen with Backlight For display of settings and menus. The screen displays Name and Frequency when powered down even with batteries removed. The screen’s backlight comes on when the battery door is open to make it easy to navigate menus and change settings in the dark.
4: Battery Door Lift to access the battery compartment, micro-SD card, power button, and navigation buttons. Closing the door returns to the Home screen.
5: Battery Door Release Catches Squeeze to unlatch and open the battery door.
A20-TX User Guide
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6: Belt Clip Mount Points For attaching the A20-TX-CLIP belt clip. The belt clip can be attached either way, so the TX can be worn up or down.
Front Panel, Battery Door Open
2
5
3
4
1
6
1: Battery Compartment Accepts up to three AA batteries. Ensure batteries are inserted with the positive terminal facing to the right. Insert negative side first for easiest insertion. See Power
2: Power Button This button is used to power the A20-TX on/off, or exit a menu.
Power On = Press and release button. Power Off = Press and hold button until `Off’ is displayed. Press to exit from a menu.
3: Left Button Press to navigate up or increase values. When in the Home screen and in the RF or RF+REC modes, press the left button to jump straight to the RF Power menu. When in the Home screen and in Rec Only mode, press the left button to jump straight to the Record menu.
4: Menu/Select Button Press to access Menu (only accessible when the door is open). Press to select menu items and store values.
5: Right Button Press to navigate down or decrease values. While in the Home screen, press the right button to jump straight to the Battery Type menu.
6: Micro SD Card Slot Insert a micro-SD for recording purposes. Top Panel
A20-TX User Guide
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1: Antenna Connector SMA connector. Attach an antenna with a length specific to the frequency in use. Using the wrong length of antenna reduces RF range. See Antenna Guide for more information.
2 & 3: A20-TX Switch Mounting Points The optional user-programmable A20-TX Switch can be mounted here. The bayonet-style switch can be set to toggle RF on/off, mute, record, Aux on/off, or power on/off.
4: Multipurpose Audio Input 3-Pin Lemo connector for connecting 2- or 3-wire lavalier microphones, balanced mic (phantom or dynamic) or line inputs, AES42, AES3, or Guitar sources. Can be set to power the transmitter on/off when a lav mic is connected/disconnected.
5: Power LED Indicates power state. Can be turned off in the Settings>LEDs menu
Green = Good battery level Orange = Medium battery level Red = Low battery Fast-Flashing Red = Critically low battery. RF, audio, and recording are disabled. Slow-Flashing Green = Charging from USB-C Solid Green = charged (when USB-C is plugged in) Blue = Displayed momentarily when pressing the power button to power up. Rapidly Alternating Red, Green, Blue = Transmitter being ID-ed from A20-Nexus or the A20-Remote app.
6: Status LED Indicates various current states. Can be turned off in the Settings>LEDs menu
Solid Blue = muted Solid Red = recording Alternate Blue/Red = both record and mute are activated. Rapidly Alternating Red, Green, Blue = Transmitter being ID-ed from A20-Nexus or the A20-Remote app. Flashing Blue = When pairing via Bluetooth to A20-Remote. Pulsing Blue = When the transmitter is powered on, timecode is syncing via NexLink.
Bottom Panel
A20-TX User Guide
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1: USB-C Port
Multifunction port used for: Charging the A20-TX’s rechargeable Li-ion AA batteries. Battery door must be closed to charge. Timecode I/O for jamming TC Transferring files to and from a computer Pairing with Astral Receivers
A20-TX User Guide
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Home Screen
The home screen is the default screen when the A20-TX is powered up. It is also automatically displayed whenever the A20-TX battery door is closed.
Important: When the A20-TX is powered on for the first time, the screen displays the following message: “To start, pair the A20-TX with the A20-Remote iOS or Android app”. Pairing enables full control of the A20-TX. Once paired, the message will not appear again. See A20-Remote for further details.
The Home Screen displays the following information:
Transmitter name RF Frequency RF Power, RF Modulation Battery level and Charging Status Mute Status Record Status Privacy Status Menu icon (when battery door is open) Firmware version (displayed for several seconds after power up)
1
2
3
4
7 5
6
8
1: Transmitter Name Displays the transmitter name (max.12 alphanumeric characters), making it easy to identify the source feeding the transmitter (e.g. actor’s name, boom, etc.) The transmitter name is used as the volume name when formatting the Micro SD card and is also embedded in metadata as the Track Name of recorded WAV files. By default, the serial number of the A20-TX is assigned as the transmitter’s name. The name can be edited wirelessly using an Astral Receiver, or A20-Remote. The A20-TX name is also displayed on the A20-RX, A10-RX, and 8-Series when docked to an A20-Nexus, A20-Nexus Go, or SL-2. The Home Screen’s transmitter name and frequency fields can be swapped. Select in the Settings>Display>Name menu.
2: Mute Status Mute is displayed when the transmitter’s audio is muted.
3: Frequency / MHz Displays the current transmission frequency.
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4: Record Status The record circle is displayed when the transmitter is recording.
5: RF Power and Modulation Type Displays the current RF power and modulation type, LR (Long Range), Std (Standard), and T&M (Test and Measurement). When RF is enabled and the battery door is open, tap the left button to shortcut directly to the RF Power menu. Displays `OFF’ when the RF Power Level is set to Off or when the optional A20-TX Switch (set to toggle RF on/off), is moved to the Off position.
6: Menu Icon When the battery door is open, tap the middle button to access the Menu.
7: Privacy Status The key icon is displayed when a privacy key is set.
8: Battery and Charging Status Displays Battery Level. Displays USB when powered from a USB power pack. When charging, a lightning icon is displayed next to the Battery Status.
A20-TX User Guide
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Power
The A20-TX features a sophisticated battery system, allowing for powering from “1.5V” AA batteries, “3.7V Li-Ion” AA batteries, or from a USB portable power pack, giving the user maximum choice and flexibility in powering the A20-TX. Unlike other systems which require expensive custom battery packs, all of the batteries used by the A20-TX are very economical and can be purchased worldwide via Amazon or other outlets. Additionally, the A20-TX features a built-in charger to recharge Li-Ion batteries via USB-C. Finally, when using rechargeable Li-Ion batteries, it is up to the user to run with either one, two, or three batteries if the additional runtime is not needed.
The choice of eco-friendly rechargeable batteries or convenient, ubiquitous primary cells is totally up to the user although for best performance, it is highly recommended to use Sound Devices XL-B14500 Li-ion batteries.
Sound Devices XL-B14500 Li-ion Batteries
1200mAh, 4.4Wh, 3.7V Lithium-Ion, rechargeable More than 10 hours battery runtime with lav input Rechargeable in the A20-TX transmitter or any charger that supports 3.7V Li-ion cells* Can power the A20-TX transmitter with 1, 2, or 3 batteries Hot-swappable to allow replacement of each battery without interrupting transmission Has built-in safety protection against excessive current draw *Supported chargers:
Recommended charger: XTAR VC8S https://www.xtar.cc/product/xtar-vc8s-charger-215.html. Other available charger: ISDT https://www.isdt.co/n8-n16-n24.html?lang=en. Note: ISDT chargers – there are
reports of intermittent detection of batteries upon insertion. Please update charger to latest firmware.
Other Supported Batteries The table below details operational characteristics for the other AA battery chemistries types compatible with the A20-TX:
Battery Chemistry
Lithium Primary
Recommended Model
Energizer Ultimate Lithium
Required No. of Batteries
3
Chargeable in the A20-TX
No
NiMH
Eneloop or Eneloop Pro
3
No
Alkaline
Energizer or Duracell
3
No
Notes:
Always use batteries of the same chemistry. Always use batteries that have the same approximate charge level. The battery remaining charge indicator will not be accurate when mixing batteries of different charge levels. All A20-TX’s LEDs will flash red if battery chemistries are mixed. It is recommended to only use the batteries listed in the table. Other models may not offer as much run time, may be less reliable, and may not report accurate battery remaining time.
About the different battery chemistries: Li-ion – We recommend using the Sound Devices XL-B14500 batteries detailed above. This is a 3.7 volt rechargeable battery. Li-ion is the same battery technology used in your cell phone. This battery features very good energy density, is lightweight, and can be recharged roughly 300 times before the capacity degrades. Lithium Primary – The only available of these is the “Energizer Ultimate Lithium” battery. This is the most energy-dense of any of these batteries. It is not rechargeable, is relatively expensive, but is lightweight, and gives the best run time of
any of these batteries. NiMH – “1.5V” or “1.2V” rechargeable batteries are the old-school tried-and-true rechargeables. These are the least
energy-dense of any of these battery types, are relatively heavy, but very available.
A20-TX User Guide
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Alkaline – “1.5V” batteries are the most ubiquitous batteries in the world, available anywhere. These are moderately energy-dense, and give adequate performance.
Batteries used in A20-TX must comply with the relevant IEC standards.
Opening/Closing the Battery Door When the door is closed, the display automatically switches to the Home screen. Open the battery door by squeezing the side panel release catches and lifting. When the door is opened, the display backlight turns on.
Powering On for the First Time When the A20-TX is powered on for the first time, the screen displays the following message: “To start, pair the A20-TX with the A20-Remote iOS or Android app”. Pairing enables full control of the A20-TX. Once paired, the message will not appear again. See A20-Remote for further details.
Powering from AA To power the A20-TX using AA batteries:
1. Open the A20-TX battery door. 2. Insert the correct number of AA batteries (see table above) into the battery compartment, taking care to place the
batteries in the correct orientation, negative terminal first with the positive battery terminal facing to the right.
Note: When inserting batteries, the A20-TX will remain powered off (or automatically power up) depending on what the power state was when the A20-TX was previously shut down.
3. Press the power button to power on the A20-TX. 4. Close the A20-TX battery door. 5. During power up, the A20-TX’s firmware version is displayed for 3 seconds below the transmitter name. 6. To power off the A20-TX, press and hold the power button until the front left LED goes solid green. `Off’ is displayed when
the A20-TX has fully powered down. 7. When powered off, the name and frequency are displayed, even without any batteries inserted. 8. To remove the batteries, open the battery door and remove the AA batteries, positive side first.
Charging from USB-C Only Li-Ion batteries can be charged in the A20-TX. To charge Li-Ion batteries from USB-C:
1. Open the Battery Door and insert the batteries into the battery compartment. 2. Close the Battery Door; it must be closed to enable charging. 3. Connect a USB power source to the A20-TX USB-C port. 4. While the batteries are charging, the top panel Battery Power LED flashes green and if the unit is on, the charging icon
appears in the ePaper display. The LED turns solid green when charging is complete. Note that RF transmission is disabled when charging except when the USB power source is a portable USB battery pack.
Auto Power with Lemo Connection When the `Auto power with Lemo connection’ feature is enabled using A20-Remote, an Astral Receiver via NexLink, or from the A20-TX System > Misc menu, connecting a source to the Lemo connector automatically powers on the transmitter. Disconnecting the Lemo automatically powers the A20-TX off.
Identify (ID)
When the A20-TX receives an ID command from an Astral receiver or the A20-Remote app: LEDs flash red, green, and blue Unit vibrates
This helps to identify which A20-TX is which when many are being used.
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Menus
Access the Menu to make changes to the A20-TX’s settings. To access the Main menu, open the battery door and press the middle button. Once in the Main Menu:
Navigate the menu items using the up/down arrow (left/right) buttons. Select an item using the middle Select button. Back out of a submenu to the menu above by using the Power button (leftmost button). Exit the Main Menu back to the Home screen by closing the battery door.
RF
Select the RF Menu to change the following settings:
Frequency: Manually enter RF frequency. Frequency can be set from 169 MHz to 1525 MHz in 25 kHz steps.
RF Power: It is recommended to use the lowest RF power that gives the desired range. This reduces the possibility of
intermodulation distortion affecting range. The lower the RF power the longer the battery run time.
2mW Low Power
10mW Normal Power
20mW High Power
40mW Extra High Power*
* Only available when the `Extra High RF Power’ option is enabled in A20-Remote or an Astral Receiver and
there are no restrictions due to the current country of operation.
Modulation: Sets the modulation mode. Ensure the receiver is set to the same modulation as the transmitter. Select from:
Long Range
Provides best range at the expense of a little extra latency (3.9 ms)
Standard
Standard range with lowest latency (2 ms)
T&M
Flattest frequency and phase response for test & measurement applications (7 ms latency)
RF On, RF Off: Toggles RF On and Off.
Pair
Select to wirelessly pair the A20-TX with the A20-Remote app or an Astral Receiver. Pairing is required to enable remote control of the A20-TX. During pairing, the display shows `Pairing. Please wait …’ and flashes blue. Once paired, the screen exits back to the Home screen. To cancel pairing, press the red button. See the A20-Remote and A20 Receiver User Guides for further information on how to pair. Pairing with an Astral Receiver can also be accomplished by connecting the USB-C port to the USB port on the receiver.
A20-TX User Guide
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Audio
Input Type
The A20-TX is compatible with many types of input sources. It autosenses the type of input plugged in (except if input type is set to 3-Wire).
Lav (2-wire lavalier mic) Select when using a 2-wire lav. The A20-TX autosenses if a 2-wire lav is plugged in except when set to 3-wire. It is not possible to select Lav unless a Lav is plugged in.
3-wire (3-wire lavalier mic) Select when using a 3-wire lav. A20-TX auto-sensing is disabled in this mode. Set to Lav or any XLR input type to re-enable auto-sensing.
XLR Input Types Mic (dynamic) Line P48 (48V phantom-powered mic) P12 (12V phantom-powered mic) AES42 (Ideal for use with the Schoeps SuperCmit or CMD42 digital microphone). AES42-1 (ch1), AES42-2 (ch2) AES3 AES3-1 (ch1), AES3-2 (ch2)
Guitar When a guitar is plugged in using the A20-TX Smart Guitar Cable, the A20-TX automatically sets the input type to Guitar unless it was set to 3-Wire since that disables input type auto-sensing. It is not possible to select Guitar unless a guitar is detected and it is not possible to select another input type when a guitar is detected. When Guitar is detected, `Guitar Settings’ is shown above the middle button. Press to access the Guitar Setting sub-menu which allows cable capacitance and impedance to be set to emulate guitar cable length and impedance to personalize the guitar’s sound characteristics. Cable Capacitance: Adjust from 0pF to 3000pF (0 – 60 feet of cable equivalent) Input Impedance: 100K, 1M (default) or 10M.
Record
The Record menu provides the ability to start and stop recording. Select Record to start recording. `Record’ changes to `Stop’ during recording. Select Stop to end recording. When set to RF Only mode, recording is not permitted. See Recording WAV Files for more information.
Privacy
Creates a randomly generated 4-digit privacy key to prevent unauthorized reception of the A20-TX’s transmitted signal. An Astral Receiver must be set to the same 4-digit key to decode and receive the RF audio.
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New Key: Select `New Key’ then press `Set’ to generate a random 4-digit key. When the key is set, the home screen displays the privacy key icon.
Clear: Select `Clear’ then press `Set’ to clear the key to 0000.
Settings
The A20-TX Settings menu provides access to the following menus:
Battery: Set the battery type to match the battery chemistry being used to ensure correct battery level monitoring. When using 1.2 to 1.5V battery types, the following options are available: Alkaline NiMH Lithium (primary) When using Li-ion batteries, no options are available.
LEDs: Turn LEDs off when you need the A20-TX to be discreet. Select from: All Off All On Top Only Front Only
Display: Orientation: Allows the display to be flipped so it can be read easily when the transmitter is upside down. Normal Flipped Background: Selects between light and dark background colors. Name: Selects whether the transmitter name is shown at the top or the center of the home screen.
Mode Select the Mode menu to choose one of three modes of operation: RF Only mode, Rec Only Mode, or Rec + RF Mode (available to International, non-US models or US models not set to Lav or Guitar input). When set to RF Only mode, `Can’t record in RF Only mode’ is displayed in the Record Menu.
Switch: Sets the function of the A20-TX’s optional Bayonet Switch. This switch can be programmed to toggle the following functions: None: No function. This is the default setting for all controls. Mute: Toggles mute on and off Record: Toggles record on and off (REC+RF and REC Only Modes) Power: Turns the A20-TX on or off. RF: Toggles RF power on and off. Aux: Aux is typically used to activate a talkback audio path. The Aux command instructs the Astral Receiver to re-route the received A20-TX audio to a different output.
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Note: The switch setting is overridden by commands coming from the A20-TX interface, A20-SuperNexus, A20-Nexus (via NexLink) or A20-Remote (via Bluetooth), which will leave the switch in the incorrect physical position. As such, it is necessary to move the switch first to the physical position that reflects the A20-TX’s current state before it will perform its next command.
See Installing the Optional Bayonet Switch.
System: Select to access the System menu.
Format: Select to format the inserted Micro SD card. Select `OK’ to start the formatting process. Once formatting is complete, `Format Success’ is displayed. Micro SD Cards 64 GB or more are formatted as ExFAT. Recommended for long duration recording. Micro SD Cards 32 GB or less are formatted as FAT32 (4GB file size limit). Max recording time is approximately 6 hours for monophonic recording and 3 hours for 2-ch recording (AES42, AES3).
Info: Displays the following information: Serial number Firmware version FPGA version Tuning bandwidth
Restore: Select Restore to restore the A20-TX to factory default settings. Once default settings have been loaded, the A20-TX returns to the Home Screen.
Time: Sets the A20-TX’s date/time clock used for file creation time. Use the up/down arrows to set values for each field and the Set button to move to the next field. Pressing Set on the Minutes field saves the date/time setting.
Note:
When connection is established with an A20-Nexus via NexLink, the date/time setting is overwritten
by the A20-Nexus’s date/time. When connection is established with A20-Remote and the transmitter’s NexLink is disabled, the date/time setting is overwritten by the mobile device’s date/time.
Misc: Various miscellaneous settings including: Auto On w/Lemo: Automatically powers on with Lemo connection [On/Off] Resume Record: Automatically resumes recording on power up [On/Off] Extra RF Power: Allows access to the extra high 40 mW RF power [Allow/Off]
FreqAuth: Displays Frequency Authorization information. Displayed only when a Frequency Authorization is loaded. See Frequency Authorization for further details.
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Tuning the A20-TX and Receiver
RF signals transmitted by the A20-TX transmitter are received by Astral Receivers, the A20-RX and Audio Ltd A10-RX. Set the same modulation and frequency on the transmitter and receiver. See the A20-SuperNexus, A20-Nexus, A20-Nexus Go, A20-RX and A10-RX User Guides for more details.
Frequency The A20-TX transmits on frequencies ranging from 169 MHz 1525 MHz. The frequencies available are determined by geographic location and whether you have entered a unique license code issued by Sound Devices to unlock the use of restricted frequencies.
Because the A20 digital RF transmission is inherently immune to intermodulation, multiple A20 Digital Wireless transmitters can be used simultaneously on nearby adjacent frequencies without worry of intermodulation interference. Systems can be used together when separated by at least 400 kHz. When operating in the 902-928 MHz Band, it is recommended to separate channel frequencies by at least 1 MHz.
Set the A20-TX’s transmit frequency from the RF > Frequency menu or via the A20-Remote App or Astral Receiver via NexLink.
Ensure an antenna with a length specific to the frequency in use is attached to the SMA connector. Using the wrong length of antenna reduces RF range. See Antenna Guide for more information.
Modulation The A20-TX offers three types of modulation, Long Range, Standard, and T&M. Long Range modulation has better sensitivity resulting in more robust performance in challenging RF environments. Standard modulation has lower latency (2ms versus the 3.9ms of Long Range). T&M modulation has been specifically optimized for the flattest frequency response and phase response possible for test and measurement applications. The Modulation setting must match between the A20-TX and A20 receivers, in order for the transmitted signal to be received.
RF Power RF power is the strength of the transmitting signal. The A20-TX offers the following RF power settings:
Low – 2 mW Normal – 10 mW High – 20 mW *Extra High – 40 mW. *This RF Power setting only appears when System > Misc > `Extra RF Power’ is set to `Allow’.
Set the A20-TX’s RF Power from the RF > RF Power menu or via the A20-Remote App or Astral Receiver.
RF Power settings are based on the selected Country of the device running A20-Remote as some legal restrictions may apply.
In situations where the transmitter is relatively close to the receiver, the Low – 2 mW setting offers good range and best battery life. For most common wireless microphone applications, the Normal – 10 mW setting provides excellent range. In situations where body absorption may be an issue or extended range is required, the High – 20 mW setting can be helpful.
If significant body absorption is unavoidable or maximum range is required, the Extra High – 40 mW setting can be enabled via the Settings menu. Please be aware that the Extra High – 40 mW RF Power setting can reduce battery life by over 20%.
Tip: Use Long Range Modulation to increase RF range prior to increasing the RF Power setting.
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Audio Levels – GainForward
The A20-TX transmitter supports GainForward, a technology that eliminates the need to adjust microphone preamplifier gain at the wireless transmitter. Audio levels from the transmitter are controlled either directly at the mixer’s digital trim control or at the wireless receiver. If the source is too soft or too loud, adjust the transmitter’s audio level with a downstream mixer’s digital trim gain control. There is absolutely no noise penalty when the audio path remains 100% digital, i.e. A20 transmitter -> A20 receiver, A20 receiver digital audio output -> mixer digital audio input. Read more about GainForward at: https://www.sounddevices.com/gainforward-explained/
Adjusting Audio of the A20-TX Signal from the A20-RX and A10-RX Receiver From the A20-RX or A10-RX home screen, press the channel’s arrow button twice to enter the Input menu. From the Input menu, press the middle button to select a sub-menu to adjust gain, low cut, or limiter of the incoming A20-TX transmitted signal.
Gain is adjustable from 0 to 60 dB. Low cut can be set to Off, 40 Hz, 60 Hz, 80 Hz, 100 Hz, or 200 Hz. Limiter can be turned on or off. The information menu displays the status of the tuned A20-TX. See the A20-RX or A10-RX User Guides for more details.
Adjusting Audio of the A20-TX Signal from the A20-SuperNexus, A20-Nexus or A20-Nexus Go Receiver See the A20-SuperNexus, A20-Nexus and A20-Nexus Go User Guides for details.
Adjusting Audio of the A20-TX Signal from the 8-Series or 688 When the A20-RX or A10-RX receiving A20-TX signal is slotted into the SL-2 or SL-6, the A20-RX or A10-RX Input menu settings are bypassed and all gain, low cut, and limiter activity are performed and controlled by the 688, 833, 888, or Scorpio. This is also the case when using an A20-Nexus or A20-Nexus Go docked to an 8-Series. See the Mixer-Recorder User Guides for more information.
Recording WAV Files
The A20-TX records 32-bit float Broadcast WAV (under 4 GB) or RF64 WAV (over 4 GB) files at 48 kHz sampling rates to a removable micro SD card (not included). 32-bit float files are recorded such that gain decisions can be made after recording. Because of the high dynamic range of the A20-TX, audio levels are never too high or too low. Learn more about 32-bit float at: https://www.sounddevices.com/a20-mini-32-bit-float-recording/
The A20-TX must be set to REC+RF or REC Only Mode.
A20-TX recording can be initiated in a number of ways including from the: A20-Remote App Astral Receivers via NexLink A20-TX Record menu or via the optional A20-TX Switch
The file name format of recorded files is: transmitter name-YYMMDDHHMMSS.WAV. For example, if the A20-TX name has been changed to “Barney” and a recording is created on July 10, 2021 at 09:30 (24 hour format), the resulting file is named Barney210710093000.WAV. All files are recorded at the root of the media (no folders).
About recording formats: The A20-TX records 1-ch monophonic 32 Bit float / 48 kHz wav files for all input types except AES42 and AES3 which record 2-ch polyphonic 32 Bit float / 48 kHz wav files comprising of channels 1 and 2 of the AES signal. For long duration recording, use a minimum Micro SD card size of 64 GB. Micro SD cards 64 GB or more are formatted as ExFAT which can record files bigger than 4 GB. Recordings that exceed 4 GB are automatically converted from standard broadcast wav to RF64 wav format. Micro SD cards 32 GB or less are formatted as FAT32 which has a 4 GB file size limit. When the 4 GB limit is reached, recording stops. For optimal performance, it is recommended to only use Micro SD cards offering a minimum of Class 10 write speed.
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Jamming Timecode
The A20-TX can be jammed wirelessly via NexLink from the A20-SuperNexus, A20-Nexus, A20-Nexus Go, or from cabled external timecode sources. The timecode value and frame rate are taken from the incoming LTC source. If timecode has not been jammed, the A20-TX starts rolling timecode from 00:00:00:00 when it is powered on.
Jammed timecode values are held for up to four hours after powering off, and up to one hour after the battery has been removed. This allows for time to swap batteries without having to re-jam timecode.
When the A20-TX is powered off with a charged battery inserted, the Audio/Timecode LED flashes blue on the 00 frame crossing to indicate timecode is being held.
To jam timecode via cable, connect a valid LTC source using one of the optional accessories, Sound Devices XL-TC-USBC-LEMO or XL-TC-USBC-BNC, to the A20-TX USB-C port. Timecode is automatically jammed once a valid LTC source is connected. After a successful timecode jam, the Audio/Timecode LED flashes blue on the 00 frame crossing.
Timecode is output from the USB-C using the Sound Devices XL-TC-USBC-LEMO, so you can verify that the A20-TX timecode is in sync with the LTC source. The Audio/Timecode LED stops flashing blue when USB-C is disconnected.
For more information about the A20-TX timecode accessory cables visit: https://www.sounddevices.com/product/xl-tc-usbc-bnc/ https://www.sounddevices.com/product/xl-tc-usbc-lemo/
A20-TX can also jam timecode from 8-Series Mixer-Recorders using a standard USB-C to USB-A cable. Connect the A20-TX to the 8-Series USB-A port. Enter the 8-Series Menu > Timecode/Sync > Jam A20 Transmitter then select Jam A20. The 8-Series Jam A20 Transmitter menu displays the current timecode frame rate and values for the 8-Series and A20-TX and displays the difference between the two units.
File Transfer to a Computer
Transfer recorded files to a computer via USB-C or Micro SD card. The A20-TX connects via USB-C to a computer as an exFAT-formatted mass storage device. Copy WAV files from the A20-TX to the computer. When file transfer is complete, eject the drive from the operating system and disconnect USB.
Recording must be stopped on the A20-TX before connecting to the computer. While connected to a computer, RF transmission, audio, and recording are disabled.
Updating Firmware
Register your A20-TX to stay informed of firmware updates. https://my.sounddevices.com/
To update your A20-TX firmware: 1. Insert a micro SD card in the A20-TX. Micro SD card is not included. 2. Format the micro SD card. See Settings > System > Format. 3. Connect the A20-TX to the computer for file transfer using a USB-C cable. 4. Download the A20-TX firmware PRG file from: https://www.sounddevices.com/download/?prod=A20-TX 5. Copy the PRG file to the root of the A20-TX micro SD card 6. Eject the A20-TX from the computer.
At this point, `Updating firmware. Please wait …’ is displayed and all the LEDs “dance” to indicate the firmware update is in progress. Once the update is completed, “Update successful. Rebooting …’ is displayed and the A20-TX reboots. The firmware update can take a few minutes to complete.
When the firmware update completes, the A20-TX automatically deletes the PRG file from the media. The firmware version is displayed for a few seconds in the Home Screen after powering up. It is also displayed in the A20-Remote App’s Manage Devices view, the A20-TX’s Settings>System>Info menu, and in the Astral Receiver’s TX List >TX View.
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A20-Remote
A20-Remote is an application for Android/iOS phones and tablets designed to pair with Astral A20 (A20-HH, A20-TX, A20-Mini) transmitters. All transmitter settings are conveniently controlled using A20-Remote.
Please refer to the A20-Remote User Guide for complete operational details https://sounddevices.com/guides/a20-remote
When connected via Bluetooth LE to the A20-TX, A20-Remote offers control and display of all A20-TX parameters, including: Power on and off the A20-TX Monitor battery status Frequency, Modulation, and RF power setup Monitor audio signal presence Microphone mute Transport controls (Record, Stop) Timecode display Media formatting and monitoring of remaining space A20-TX settings (Mode, XLR Input Type, Lav Mic Type, Display, LEDs, Power options, and more) Group control of powering, recording, and more
Download and install the A20-Remote app from the Google Play Store or Apple App Store. https://www.sounddevices.com/a20-remote
A20-Remote has the following minimum operating requirements: Android tablets and phones running Android 8+, or iPad and iOS devices running iOS 13+. The device must have Bluetooth and Location Services on in order to connect with an A20 Transmitter.
IMPORTANT: The mobile device’s location is used to determine available frequencies, RF power levels, and TV channel mapping of the A20 transmitter. The Country setting is automatically set using the mobile device’s Location Services.
The mobile device’s system date and time are used in the metadata of recorded files.
SD-Utility
Sound Devices SD-Utility is a companion application for MacOS and Windows that supports Sound Devices wireless products. This application can be used to process files recorded by A20 transmitters to be more suited to the given workflow. A20 transmitter 32-bit float, 48 kHz, monophonic WAV, 2ch polyphonic WAV, and RF64 WAV files can be imported, renamed, snipped by timecode values, converted to 24 bit, conformed to a CSV Sound Report, exported as monophonic or polyphonic WAV, and more.
Please refer to the SD-Utility User Guide for complete install and operational details https://sounddevices.com/guides/sd-utility
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Accessories
Included
Antenna set 1 straight 470-548 MHz to SMA 1 straight 548-638 MHz to SMA 1 straight 17″ uncut Astral VHF Whip Antenna (SMA) 3 antenna caps
A20-TX Belt Clip
Optional
Astral Sleeve A20-TX Belt Clip A20-TX Switch A-BOOM 2 Boom Pole Mount 1 straight 17” uncut Astral VHF Whip Antenna (SMA) A20-TX Smart Guitar Cable A20-TX Smart Guitar Cable (right-angled) A20-TX Guitar Strap Clip
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Installing the Optional A20-TX Switch
The optional A20-TX Switch is a physical latching on/off bayonet-style switch that mounts to the top of the A20-TX. It can be assigned to the following functions:
None Power Record Mute RF Aux
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Installing the Optional A-BOOM 2
The A-BOOM 2 is a boom pole mount designed specifically for the A20-TX transmitter. It mounts to the top of a cabled or cableless boom pole. It can be positioned facing up or down the boom pole, and the onscreen text of the A20-TX screen will conveniently rotate to allow you to read it at the right orientation.
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Frequency Authorization
The wireless system operator needs to be aware of local regulations and comply with all applicable laws regarding operation of wireless devices.
Frequency Authorizations allow the unlocking of restricted frequencies that require proof of a valid license before they can be used. Once a license has been granted, please contact Sound Devices (RF_Request@SoundDevices.com) to obtain the necessary authorization. An Authorization ID and License Code will be generated by Sound Devices based on the license provided. The Authorization ID or License Code can be entered into the A20-Remote App and then synchronized with an A20-Nexus Go, A20Nexus, or A20-SuperNexus receiver and its paired A20 transmitters.
An example of a frequency band requiring an unlock code in the United States is 1435-1525 MHz. Program Making and Special Events (PMSE) wireless operators typically call 1435-1525 MHz the “AFTRCC band”. AFTRCC stands for Aerospace and Flight Test Band Coordinating Council. This organization coordinates a number of frequency bands for use by air and spacecraft in the United States. This includes 1435-1525 MHz.
Per the United States Federal Communications Commission (FCC) rules, wireless microphones are allowed as secondary users in the 1435-1525 MHz AFTRCC band. This is detailed in the FCC Part 74 rules:
https://www.ecfr.gov/current/title-47/chapter-I/subchapter-C/part-74
One section of the Part 74 rules that’s of particular interest to operators seeking an AFTRCC band license is 74.803(d):
https://www.ecfr.gov/current/title-47/chapter-I/subchapter-C/part-74#p-74.803(d)
Generally speaking, a wireless operator needs to show they’ve used all other available spectrum before the AFTRCC will consider a license request in the 1435-1525 MHz range. If granted, the license is normally assigned for a specific location and a specific time range.
Sound Devices encourages all wireless operators to obtain a Part 74 license, and specifically to make sure applicable parts of the 600 MHz and 950 MHz range are included with their license application. This can help show an operator is aware of the available spectrum and is utilizing it responsibly.
More information on Part 74 licensing can be found here: https://www.local695.com/fcc-licensing/
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A20-TX Specifications
Specifications are subject to change without prior notice. For the latest information available on all Sound Devices products, visit our website: www.sounddevices.com.
Frequency Range 169 to 1525 MHz Transmitter tunable in 25 kHz steps Available frequencies are dependent on region
RF Output Power Off, Low – 2 mW, Normal – 10 mW, High – 20 mW, Extra High – 40 mW
Modulation Mode Proprietary, 100% digital RF modulation Standard, Long Range, T&M (Test & Measurement), selectable
Latency – Lemo input to Receiver analog output Standard (2 ms) Long Range (3.9 ms) T&M (7 ms)
Antennas UHF RF: SMA connector, removable antenna 2.4 GHz built-in, bottom of unit
Audio Frequency Response 10 Hz – 20 kHz, +/- 1 dB re 1 kHz
Audio Input Lavalier Microphone 2-wire- or 3-wire-type lavalier mics supported Auto-selected when lavalier mic connected to Lemo input, except when set to `3-Wire’. Dynamic range: 134 dB min, A-weighted Input clip level: 5V p-p (limited by lavalier microphone) `Lav’ setting: Lemo pin 1/Shell = ground; Lemo pin 2 = floating; Lemo pin 3 = audio/bias `3-Wire’ setting: Lemo pin 1/Shell = ground; Lemo pin 2 = bias; Lemo pin 3 = audio Auto unit power on/off with connection/removal of lavalier microphone (menu selectable) Balanced Mic True, fully balanced, 8-Series mic preamp Dynamic range: 140 dB min, A-weighted Menu selectable with connection of XL-BALXLR-4 cable to Lemo input Phantom power: 12V or 48V, full 10mA available per IEC 61938 XLR pin 1 = ground; XLR pin 2 = +; XLR pin 3 = Line Input True, fully balanced line-level input (no external resistors required) Input clip level: +26 dBu Menu selectable with connection of XL-BALXLR-4 cable to Lemo input XLR pin 1 = ground; XLR pin 2 = +; XLR pin 3 = AES42 AES digital input with common mode power for Digital mics such as Schoeps SuperCMIT 250mA current available Selectable audio channel 1 or 2 via menu Menu selectable with connection of XL-BALXLR-4 cable to Lemo input XLR pin 1 = ground; XLR pin 2 = +; XLR pin 3 = AES3 AES digital input without common mode power Selectable audio channel 1 or 2 via menu Menu selectable with connection of XL-BALXLR-4 cable to Lemo input XLR pin 1 = ground; XLR pin 2 = +; XLR pin 3 = Guitar Auto-selected when connected with A20-TX Smart Guitar Cable
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¼” tip = + ¼” sleeve = ground 18V p-p max input level Input impedance: 100k, 1M, 10M (menu selectable) Cable capacitance: 0 pF – 3000 pF in 50 pF steps (menu selectable) Balanced connection from ¼” plug to Lemo for low noise susceptibility
Menu and Controls
e-Paper screen highly visible in direct sunlight e-Paper screen keeps display even with no batteries Power/Pair button and three navigation buttons protected inside battery compartment Optional user-programmable bayonet switch for top of transmitter (A20-TX Switch)
Remote Control A20-Remote Android, iOS, and iPad app via Bluetooth 5.2 LE A20-SuperNexus, A20-Nexus, A20-Nexus Go receivers via super-long-range NexLink
Recording Media Micro SD card. Minimum Class 10 write speed. Media format: ExFAT for Micro SD cards 64GB or more, FAT32 for Micro SD cards 32GB or less.
Recording File Format 32 Bit Float, 48 kHz, Monophonic (Lav, Mic, Line, P12, P48, Guitar) 32 Bit Float, 48 kHz, 2ch polyphonic (AES42, AES3) Broadcast WAV (<4 GB), RF64 WAV (>4 GB)
Simultaneous Record and Transmit mode when using lavalier mic or guitar input is not available on A20-TX units sold or operated in the United States of America.
Timecode Input via XL-TC-USBC-LEMO, XL-TC-USBC-BNC, USB-A to USB-C (from 8-Series) or wirelessly over NexLink (from A20-SuperNexus/A20-Nexus/A20-Nexus Go) LTC: 0.3 V – 3 V p-p (17 dBu to +3 dBu), 20k ohm impedance LTC Output via XL-TC-USBC-LEMO: 3 V p-p, 400 ohm impedance
Timecode Clock 0.2 ppm accuracy Holds accurate clock for four hours while powered down with batteries inserted, holds for one hour without batteries via internal supercapacitor Auto Jams timecode via USB-C connector or wirelessly via NexLink
Timecode Frame Rates 23.98, 24, 25, 29.97 DF, 29.97 ND, 30 DF, 30 ND Frame rates are auto detected from incoming source
USB-C
Mass Storage (USB-C): USB 2.0 high speed for file transfer Charges Li-ion batteries inserted in A20-TX Pairing to A20-Nexus, A20-Nexus Go Timecode I/O
Powering
“1.5V” Alkaline, Lithium primary, NiMH AA batteries; 3 for operation “3.7V” Rechargeable Lithium-Ion, 1, 2, of 3 for operation Energizer Ultimate AA primary cells recommended for longest runtime
Battery Charging Built-in charging of Li-ion batteries via USB-C
Battery Runtime Up to 12 hours (depending on battery chemistry, number of batteries, RF power, input type, mode) Unit can be completely powered off remotely via app or via NexLink to extend battery runtime
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Environmental Operating: -10° C to 40° C Storage: -40° C to 85° C 0 to 90% relative humidity (non-condensing)
Dimensions (H x W x D) 3.3 x 2.5 x 0.71 in 8.5 x 6.4 x 1.81 cm
Weight 0.2lbs (without batteries) 98g (without batteries)
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Antenna Guide
The A20-TX ships with an antenna set with three antennas (1 straight 470-548 MHz to SMA, 1 straight 548-638 MHz to SMA, 1 straight 17″ uncut Astral VHF Whip Antenna to SMA), and a set of antenna caps.
Sound Devices offers additional pre-cut and uncut antennas as available options.
Attach antennas with a length specific to the frequency in use. Using the wrong length of antenna reduces RF range.
Cutting Antennas to Length Uncut antennas need to be cut to the length specific to the frequency for intended use.
1. Determine the frequency range intended for the uncut antenna using the Antenna Length chart. 2. Measure the antenna for the cut point. Measurements should begin from the bottom of the SMA connector. 3. Using a pair of cutters, cut the quarter-wave antenna at the specified cut point. 4. Position the antenna cap onto the cut-end of the antenna and push the cap firmly onto the antenna.
Antenna Length Chart
Frequency Range Antenna Length in mm Antenna Length in inches
169 – 216 MHz 470 – 548 MHz 548 – 663 MHz 638 – 738 MHz 738 – 865 MHz 902 – 1015 MHz 1045 – 1154 MHz 1240 – 1260 MHz 1350 – 1525 MHz
388 mm 140 mm 120 mm 104 mm 89 mm 74 mm 65 mm 57 mm 49 mm
15.28″ 5.51″ 4.72″ 4.09″ 3.50″ 2.92″ 2.55″ 2.24″ 1.93″
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Servicing the A20-TX
Do not attempt to service the A20-TX. The case is water-sealed and needs to have new gaskets installed if taken apart. The internal parts are microscopic and not user serviceable. Please send to Sound Devices for any service needs. https://service.sounddevices.com/contact-support/
Warranty
Sound Devices, LLC warrants the items listed above against defects in materials and workmanship for a period of ONE (1) year from date of original retail purchase. Users who register their product directly with Sound Devices Technical Support using the online form or by phone, will receive an additional ONE (1) year of warranty coverage, extending the complete warranty period to TWO (2) years from the date of original retail purchase. In order to extend the warranty coverage period, registration must b e completed within the initial ONE (1) year warranty period. Products must be purchased through authorized Sound Devices resellers to qualify for Warranty coverage. Damage resulting from the opening of a Sound Devices product or attempted repairs by a nonauthorized Sound Devices repair technician will void warranty coverage.
This is a non-transferable warranty that extends only to the original purchaser. Sound Devices, LLC will repair or replace the product at its discretion at no charge. Warranty claims due to severe service conditions will be addressed on an individual basis.
THE WARRANTY AND REMEDIES SET FORTH ABOVE ARE EXCLUSIVE. SOUND DEVICES, LLC DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. SOUND DEVICES, LLC IS NOT RESPONSIBLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING FROM ANY BREACH OF WARRANTY OR UNDER ANY OTHER LEGAL THEORY. Because some jurisdictions do not permit the exclusion or limitations set forth above, they may not apply in all cases.
For all service, including warranty repair, please contact Sound Devices for an RMA (return merchandise authorization) before sending your unit in for repair. Product returned without an RMA number may experience delays in repair. When sending a unit for repair, please do not include accessories, including SSD drives, CF cards, batteries, power supplies, carry cases, cables, or adapters unless instructed by Sound Devices. Sound Devices repairs and replacements may be completed using refurbished, returned or used parts that have been factory certified as functionally equivalent to new parts.
Sound Devices, LLC
Services Repair RMA #XXXXX
E7556 State Road 23 and 33 Reedsburg, WI 53959 USA Telephone: +1-608-524-0625
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Patents
This product is covered under patent number 9,654,134 and other patents pending.
Legal Notices
Product specifications and features are subject to change without prior notification. Read and fully understand this manual b efore operation.
Copyright© 2023 Sound Devices, LLC. All rights reserved. This product is subject to the terms and conditions of a software license agreement provided with the product, and may be used in accordance with the license agreement. This document is protected under copyright law. An authorized licensee of this product may reproduce this publication for the licensee’s own personal use. This document may not be reproduced or distributed, in whole or in part, for commercial purposes, such as selling copies or providing educational services or support. This document is supplied as a technical guide. Special care has been taken in preparing the information for publication; however, since product specifications are subject to change, this document might contain omissions and technical or typographical inaccuracies. Sound Devices, LLC does not accept responsibility for any losses due to the use of this guide.
LIMITATION ON SOUND DEVICES’ LIABILITY. TO THE FULLEST EXTENT PERMITTED BY LAW, SOUND DEVICES SHALL HAVE NO LIABILITY TO THE END USER OR ANY OTHER PERSON FOR COSTS, EXPENSES, DIRECT DAMAGES, INCIDENTAL DAMAGES, PUNITIVE DAMAGES, SPECIAL DAMAGES, CONSEQUENTIAL DAMAGES OR OTHER DAMAGES OF ANY KIND OR NATURE WHATSOEVER ARISING OUT OF OR RELATING TO THE PRODUCTS, THESE TERMS AND CONDITIONS OR THE PARTIES’ RELATIONSHIP, INCLUDING, WITHOUT LIMITATION, DAMAGES RESULTING FROM OR RELATED TO THE DELETION OR OTHER LOSS OF AUDIO RECORDINGS OR DATA, REDUCED OR DIMINISHED AUDIO QUALITY OR OTHER SIMILAR AUDIO DEFECTS ARISING FROM, RELATED TO OR OTHERWISE ATTRIBUTABLE TO THE PRODUCTS OR THE END USER’S USE OR OPERATION THEREOF, REGARDLESS OF WHETHER SUCH DAMAGES ARE CLAIMED UNDER CONTRACT, TORT OR ANY OTHER THEORY. “CONSEQUENTIAL DAMAGES” FOR WHICH SOUND DEVICES SHALL NOT BE LIABLE SHALL INCLUDE, WITHOUT LIMITATION, LOST PROFITS, PENALTIES, DELAY DAMAGES, LIQUIDATED DAMAGES AND OTHER DAMAGES AND LIABILITIES WHICH END USER SHALL BE OBLIGATED TO PAY OR WHICH END USER OR ANY OTHER PARTY MAY INCUR RELATED TO OR ARISING OUT OF ITS CONTRACTS WITH ITS CUSTOMERS OR OTHER THIRD PARTIES. NOTWITHSTANDING AND WITHOUT LIMITING THE FOREGOING, IN NO EVENT SHALL SOUND DEVICES BE LIABLE FOR ANY AMOUNT OF DAMAGES IN EXCESS OF AMOUNTS PAID BY THE END USER FOR THE PRODUCTS AS TO WHICH ANY LIABILITY HAS BEEN DETERMINED TO EXIST. SOUND DEVICES AND END USER EXPRESSLY AGREE THAT THE PRICE FOR THE PRODUCTS WAS DETERMINED IN CONSIDERATION OF THE LIMITATION ON LIABILITY AND DAMAGES SET FORTH HEREIN AND SUCH LIMITATION HAS BEEN SPECIFICALLY BARGAINED FOR AND CONSTITUTES AN AGREED ALLOCATION OF RISK WHICH SHALL SURVIVE THE DETERMINATION OF ANY COURT OF COMPETENT JURISDICTION THAT ANY REMEDY HEREIN FAILS OF ITS ESSENTIAL PURPOSE.
The “wave” logo is a registered trademark of Sound Devices, LLC. Windows is a registered trademark of Microsoft Corporation in the U.S. and other countries. Bluetooth LE is a registered trademark of Bluetooth SIG, Inc. Android is a registered trademark of Google. iPad, iPhone, and iOS are registered trademarks of Apple Inc. All other trademarks herein are the property of their respective owners.
FCC Conformity
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. Changes or modifications not expressly approved by the manufacturer could void the user’s authority to operate the equipment.
Warning! Any modifications or changes made to this device, unless explicitly approved by Sound Devices may invalidate the authorization of this device. Operation of an unauthorized device is prohibited under Section 302 of the Communications act of 1934, as amended, and Subpart 1 of Part 2 of Chapter 47 of the Code of Federal Regulations.
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This device must be installed by trained professionals.
FCC Radiation Exposure Statement This equipment complies with FCC radiation exposure limits set forth for portable conditions. In accordance with FCC requirements, this device has been tested and found to comply with radiation exposure limits for portable conditions..
ISED Radiation Exposure Statement This equipment complies with ISED radiation exposure limits set forth for portable conditions. This device complies with the Specific Absorption Rate (SAR) requirements at a distance of 0mm.
Cet équipement est conforme aux limites d’exposition aux rayonnements ISED établies pour des conditions portables. Cet appareil est conforme aux exigences de débit d’absorption spécifique (SAR) à une distance de 0 mm.
This device has been approved to operate with the antenna types listed below:
Sound Devices Part # Frequency Band
Maximum Gain
29429.000
169-172 MHz, 174-216 MHz
+2.15 dBi
9162.001
470-548 MHz
+2.15 dBi
11225.000 28255.000 28257.000
548-608 MHz, 614-616 MHz, 653-657 MHz, 657663 MHz
+2.66 dBi
902-928 MHz, 941.5-952 MHz, 952.85-956.25 MHz, +3.47 dBi 956.45-959.85 MHz
1435-1525 MHz
+2.15 dBi
Impedance 50 ohms 50 ohms 50 ohms 50 ohms 50 ohms
FCC Interference Statement This equipment 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 residential installation. 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. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following m easures:
Reorient or relocate the receiving antenna Increase the separation between the equipment and receiver Connect the equipment into an outlet on a circuit different from that to which the receiver is connected Consult the dealer or an experienced radio/TV technician for help
Industry Canada Conformity This device operates on a no-interference, no-protection basis. Should the user seek to obtain protection from other radio services operating in the same TV bands, a radio licence is required. For further details, consult Innovation, Science and Economic Development Canada’s Client Procedures Circular CPC-2-1-28, Voluntary Licensing of Licence-Exempt Wireless Microphones in the TV Bands.
This radio transmitter 22225-9808 has been approved by Innovation, Science and Economic Development Canada to operate with the antenna types listed below, with the maximum permissible gain indicated. Antenna types not included in this list that have a gain greater than the maximum gain indicated for any type listed are strictly prohibited for use with this device.
Sound Devices Part # Frequency Band
29429.000
169-172 MHz, 174-216 MHz
9162.001
470-548 MHz
11225.000
548-608 MHz, 614-616 MHz, 653-657 MHz, 657663 MHz
Maximum Gain +2.15 dBi +2.15 dBi +2.66 dBi
Impedance 50 ohms 50 ohms 50 ohms
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28255.000 28257.000
902-928 MHz, 941.5-952 MHz, 952.85-956.25 MHz, +3.47 dBi 956.45-959.85 MHz
1435-1525 MHz
+2.15 dBi
50 ohms 50 ohms
The transmitter is supplied with the above unique antenna types; to replace a lost, damaged or faulty antenna, please contact Sound Devices, LLC.
This Device complies with Industry Canada Licence-exempt RSS standard(s). Operation is subject to the following two conditions: 1) this device may not cause interference, and 2) this device must accept any interference, including interference that may cause undesired operation of the device.
Conformité à Industrie Canada Cet appareil opère selon un régime de non-brouillage et de non-protection. Si l’utilisateur veut obtenir une protection par rapport aux autres services radio opérant sur les mêmes bandes TV, une licence radio est requise. Pour plus de détails, veuillez consulter le circulaire de procédures client CPC-2-1-28 Délivrance de licenses sur une base volontaire pour les microphones sans fils exempts de licence exploités dans les bandes de télévision, publié par Innovation, Sciences et Développement économique Canada.
Ce transmetteur radio 22225-9808 a été approuvé par Innovation, Sciences et Développement économique Canada pour opérer avec les types d’antennes listés ci-dessous, avec gain maximum permissible indiqué. Les types d’antennes non inclus dans cette liste et dont le gain excède le gain maximum indiqué sur n’importe quel type listé ci-dessous sont strictement prohibés d’utilisation avec cet appareil.
Sound Devices Part # Frequency Band
Maximum Gain
29429.000
169-172 MHz, 174-216 MHz
+2.15 dBi
9162.001
470-548 MHz
+2.15 dBi
11225.000 28255.000 28257.000
548-608 MHz, 614-616 MHz, 653-657 MHz, 657663 MHz
+2.66 dBi
902-928 MHz, 941.5-952 MHz, 952.85-956.25 MHz, +3.47 dBi 956.45-959.85 MHz
1435-1525 MHz
+2.15 dBi
Impedance 50 ohms 50 ohms 50 ohms 50 ohms 50 ohms
Ce transmetteur est fourni avec les types d’antenne unique ci-dessus; pour remplacer une antenne perdue, endommagée ou défectueuse, veuillez contacter Sound Devices, LLC.
Cet appareil est conforme aux normes CNR exemptes de licence d’Industrie Canada. Son fonctionnement est soumis aux deux conditions suivantes: 1) ce dispositif ne peut pas causer d’interférences, et 2) ce dispositif doit accepter toute interférence, y compris les interférences qui peuvent causer un mauvais fonctionnement de l’appareil.
USA White-Space Operation For USA operation in the 600 MHz guard band (614-616 MHz) and 600 MHz duplex gap (657 – 663 MHz) users are advised to register with and check a white-space database to determine available channels prior to operation at a given location.
WEEE Statement If you wish to discard a Sound Devices product in Europe, contact Sound Devices (England) for further information.
Battery Advisory Incorrect use of batteries poses a danger of explosion. Replace only with the same or equivalent type. Properly recycle batteries. Do not crush, disassemble, incinerate, dispose of in a fire, or expose batteries to high temperatures.
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Declaration of Conformity
Manufacturer’s Name:
Sound Devices, LLC
Manufacturer’s Address: E7556 State Road 23 and 33 Reedsburg, WI 53959 USA
We, Sound Devices, LLC, declare under our sole responsibility that the product
Product Name: Model Number: Description:
A20-TX 9808 Digital Wireless Microphone Transmitter
is in conformity with the essential requirements of the following relevant Union harmonisation legislation:
Radio Equipment Directive (RED) Low Voltage Directive RoHS Directive
2014/53/EU 2014/35/EU 2011/65/EU
The following harmonised standards and/or normative documents were applied:
Health & Safety (Article 3.1(a) of RED) EN 62368-1:2014 EN 50566:2017
EMC (Article 3.1(b) of RED)
EN 301-489-1 v2.2.3:2019 EN 301-489-9 v2.1.1:2019 EN 301-489-17 v3.2.4:2020
RF Spectrum (Article 3.2 of RED)
EN 300 422-1 v2.2.1:2021 EN 300 328 v2.2.2:2019 EN 300 440 v2.1.1:2017
Signed for and on behalf of Sound Devices LLC:
July 20th, 2023
__________________________________ Date
______________________________________ Matt Anderson – Sound Devices, LLC President
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Documents / Resources
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SOUND DEVICES A20-TX Digital Wireless Bodypack Transmitter [pdf] User Guide A20-TX Digital Wireless Bodypack Transmitter, A20-TX, Digital Wireless Bodypack Transmitter, Wireless Bodypack Transmitter, Bodypack Transmitter |