Sound Devices A20-Mini Transmitter

[vc_row][vc_column][thim-heading title=”A20-Mini” main_title=”Transmitter” title_uppercase=”true” clone_title=”” line=”true”][vc_column_text]The Sound Devices A20-Mini is a miniature transmitter that is extremely jam-packed with features without exploding too many variables on the transmitters themselves. There are no menus or switches; having only one button underneath the battery door for powering on the A20-Mini as well as pairing it to a mobile device for controlling purposes.

The A20-Transmitter also has the capability of recording and transmitting at the same time (International Only). If you are purchasing units in the US, you will be subject to transmitters that will either Record OR Transmit, not both.[/vc_column_text][thim-gallery-images image=”21741,21747,21743″ image_size=”Medium”][thim-heading title=”A20-Mini” main_title=”Size” title_uppercase=”true” clone_title=”” line=”true”][vc_column_text]In their live training broadcast, Kishore Patel describes the A20-Mini size as being extremely small and “feels like a bar of soap”. There are no sharp edges, making this transmitter easy on the eyes and less bulky inside of pockets. It is a beautiful small transmitter that will be greatly received by your talent.[/vc_column_text][vc_single_image image=”21742″ img_size=”Medium” alignment=”center”][thim-heading title=”A20-Mini” main_title=”Mic Input” title_uppercase=”true” clone_title=”” line=”true”][vc_column_text]The Sound Devices A20-Mini has a 3-Pin LEMO connector for connecting a lavalier microphone. When the transmitter senses a microphone, it can be programmed to instantly turn on, and back off again when it is unplugged.

There are no meters to monitor, only an Audio/Timecode LED, which indicates audio activity and timecode status. The meters are underneath the chassis of the device and bleed through the corners of the unit in a very beautiful way you have to see up close to fully appreciate.[/vc_column_text][vc_column_text]When Auto Power with Lav Mic Connection is selected, connecting a lavalier microphone to the A20-Mini automatically powers on the transmitter. Removing the LEMO connection automatically powers the A20-Mini off.
This feature can be turned on or off in the A20-Remote application. See A20-Remote for more details.[/vc_column_text][thim-heading title=”A20-Mini” main_title=”USB-C PORT” title_uppercase=”true” sub_heading=”What is the USB-C Port on the A20-Mini For?” clone_title=”” line=”true”][vc_column_text]

The USB-C on the back of the Sound Devices A20-Mini is a multifunctional port. It is used to jam timecode into your A20-Mini as well as power the transmitter and charge its internal battery (if using the Sony NP-BX1). 

[/vc_column_text][thim-heading title=”A20-Mini” main_title=”Antenna Port” title_uppercase=”true” clone_title=”” line=”true”][vc_column_text]SMA connector. Attach 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.[/vc_column_text][thim-heading title=”What is Gain” main_title=”Forward?” title_uppercase=”true” clone_title=”” line=”true”][vc_column_text]To learn even more about GainForward, check out Sound Devices’ article on the topic here.[/vc_column_text][thim-heading title=”32BIT” main_title=”AUDIO RECORDER” title_uppercase=”true” clone_title=”” line=”true”][vc_column_text]To learn more about 32bit Recording, Sound Devices did a great write-up on what it is and how it is used properly. Check it out here!


[/vc_column_text][thim-heading title=”A20-Mini” main_title=”Specifications” title_uppercase=”true” sub_heading=”All Specifications Are Subject To Change” clone_title=”” line=”true”][thim-heading title=”A20″ main_title=”Remote” title_uppercase=”true” sub_heading=”iOS/Android Application for the A20-Mini” clone_title=”” line=”true”][vc_column_text]

The A20-Remote is a mobile-based application for Android and iOS devices that pairs with the A20-Mini. All settings for the A20-Mini can be controlled using A20-Remote using a Bluetooth LE connection.

The A20-Remote offers control and display of all A20-Mini parameters, including:

  1. Power on and off the A20-Mini
  2. Monitor battery status
  3. Frequency and RF power setup
  4. Monitor audio signal presence
  5. Microphone mute
  6. Transport controls (Record, Stop)
  7. Timecode display
  8. Media formatting and monitoring of remaining space
  9. A20-Mini settings (Mode, power options, and more)

Download and install the A20-Remote app from the Google Play Store or Apple App Store.

[/vc_column_text][thim-heading title=”A20-Mini” main_title=”Battery Life” title_uppercase=”true” clone_title=”” line=”true”][vc_column_text]

Estimated Battery Life

The tables to the right show estimated battery rundown times in Hours:Minutes for Sony NP-BX1 Li-Ion and three Energizer Ultimate AAA Lithium primary batteries based on RF Power setting and whether the A20-Mini is recording.

The first chart shows estimated battery life under continuous use and the second chart shows battery life when utilizing the A20-Mini’s ability to power the unit on and off remotely from the A20-Remote app when the transmitter is not in use. Estimates are based on a 50% duty cycle.

Battery Life Estimate for A20-Mini


Battery Power LED


Indicates the state of battery life.
• Green = Good
• Orange = Marginal, about an hour of battery life remaining. • Red = Low, 15-20 minutes of battery life remaining.
• Flashing Red = Critically low, RF,

audio, and recording disabled.
• Blue = Batteries inserted. Power LED is blue

When batteries are inserted and goes off when the unit is ready to be powered on by the red button or from the A20-Remote app.


[/vc_column_text][thim-heading title=”Powerstation” main_title=”8M” title_uppercase=”true” clone_title=”” line=”true”][vc_column_text]

The PowerStation-8M is an optional accessory for the A20-Mini. An A20-Mini using a Sony NP-BX1 battery can be inserted into a charging bay of the PowerStation-8M to charge the battery. See PowerStation-8M for more details.

Auto Power On and Off with PowerStation-8M

The A20-Mini automatically powers off when inserted into a charging bay of the PowerStation-8M. To save time from having to manually power on the A20-Mini, use the Power On When Removed from the PowerStation-8M feature. When this feature is selected, removing an A20-Mini from the PowerStation-8M immediately powers on the transmitter. This feature is turned on or off in the A20-Remote application. See A20-Remote for more details.

The PowerStation-8M is powered via 12 VDC TA-4 connector or USB-PD power supply. The supplied 36 W USB-PD power supply supports full operation. Make certain third-party USB-C power supplies offer 36 W or higher in order to charge all eight A20-Mini transmitters at a time. Make certain any external supply connected to the TA-4 connector supplies at least 36 W.

Distributing Timecode to A20-Mini Transmitters

The PowerStation-8M is equipped with a Timecode input on BNC. Connecting a valid LTC timecode source to the PowerStation-8M jams the frame rate and timecode value
to all inserted A20-Mini transmitters. The A20-Mini bottom panel Timecode LED flashes blue on the 00 frame following a successful jam.

Transferring A20-Mini Files via PowerStation-8M

The File Transfer USB-C connector is used to connect A20-Mini transmitters slotted into the PowerStation-8M to a computer as mass storage devices. Each connected A20-Mini transmitter will appear as its own mass storage device when the PowerStation-8M is connected to a computer. The PowerStation-8M USB-C connector is SuperSpeed USB

(5 Gb/s) offering maximum transfer speeds when all eight slots are filled.

The File Transfer LED lights red when USB-C File Transfer
is plugged in without a power adapter connected. The File Transfer LED lights green when USB-C File Transfer and either TA-4 or USB-PD are plugged in.

See File Transfer to a Computer for more information.

Updating A20-Mini Firmware via PowerStation-8M

Using File Transfer in combination with the PowerStation-8M, Firmware can be updated on up to eight A20-Mini transmitters.

[/vc_column_text][thim-heading title=”A20-Mini” main_title=”Specifications” title_uppercase=”true” sub_heading=”All Specifications Are Subject To Change” clone_title=”” line=”true”][vc_column_text]

Frequency Range

• 470 to 694 MHz
• Transmitters are tunable in 25 kHz steps
• Available frequencies are dependent on region

RF Output Power

• Off,Low-2mW,Normal-10mW, High – 20 mW, Max -40 mW, selectable

Modulation Mode

• Sound Devices proprietary digital RF modulation


• UHF RF: SMA connector, removable

• 2.4GHzbuilt-in

Audio Frequency Response

• 10Hz-20kHz,+/-1dBre1kHz

Audio Input Type

• Lavalier Microphone via 3-pin LEMO • Pin-1 ground
• Pin-2 5V bias
• Pin-3 audio/bias (8k ohm to 5 V)

Recording Media

• Internal 64 GB

• 10% over-provisioned for optimum performance

Recording File Format

• 32 Bit Float, 48 kHz, Monophonic
• Broadcast WAV (<4 GB), RF64 WAV (>4 GB)

Simultaneous Record and Transmit mode is not available on A20-Mini units sold or operated in the United States of America.

Timecode Input

• USB-C connector: 20k ohm impedance, 0.3V-3.0Vp-p(–17dButo+3dBu)

Timecode Clock

• 0.2ppmaccuracy
• Holds accurate clock for 4 hours while powered down with batteries inserted, holds for 1 hour without batteries via internal supercap

• Auto Jams timecode from LTC source via USB-C connector, or from optional PowerStation-8M

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


• Mass Storage (USB-C): USB 2.0 high speed for file transfer • Powers A20-Mini


3x AAA batteries (Energizer Ultimate AAA Lithium primary batteries recommended), or Sony NP-BX1 rechargeable Li-Ion

Built-in Li-Ion charger via USB-C (7.5 W or more needed)

Sony NP-BX1 is rechargeable via

optional PowerStation-8M.


• Water Resistant

• Operating: -20° C to 60° C, 0 to 90% relative humidity (non-condensing)

• Storage: -40° C to 85° C

Dimensions (H x W x D)

• 75.8mmx48mmx19mm

• 2.98inx1.88inx0.74in


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Bias Power

• 5V

Input Impedance

• 8k ohms

Input Clipping Level

• +5dBu

Dynamic range

• 130 dB min (A-weighted)

Menu and Controls

• Power & Pair button protected inside battery compartment • A20-Remote, mobile device application

of iOS, iPad, and Android

Remote Control

• A20-Remote Android, iOS, and iPad app via Bluetooth 5.2 LE


51 g (without batteries)

1.8 oz (without batteries)


Antenna Guide

The A20-Mini ships with an antenna set with three antennas (1 straight 470-548 MHz, 1 straight 548-638 MHz, 1 straight uncut, 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.

[/vc_column_text][vc_single_image image=”21755″ img_size=”large” alignment=”center”][vc_column_text]With which receiver is the A20-Mini compatible?

The Audio Limited A10-RX.

Can the A20-Mini use balanced microphones?

No, the A20-Mini is specially designed for small size, and supports lav mics only. For using 48V phantom, balanced mics or balanced line sources, please use the A10-TX.

What is the Bluetooth range on the A20-Mini?

Many things in the environment can affect Bluetooth range, but line-of-sight you can typically expect upwards of 40 feet and not-line-of-sight, upwards of 20 feet.

Can the A20-Mini use both 2-wire and 3-wire lav microphones?

Yes, unlike the A10-TX which only supported lavs which are 2-wire, the A20-Mini also supports 3-wire lavs such as the Schoeps CMR.

With GainForward’s high dynamic range, does this mean I don’t need to have low-sensitivity lavs anymore such as the Sanken COS-11 red dot? 

No, low-sensitivity microphones are still needed for very loud sounds. Lavalier microphones themselves inherently have a more limited dynamic range than larger diaphragm microphones. Even though the A20-Mini itself can handle the entire acoustical and electrical dynamic range of any lav microphone plugged into it, lavs themselves can saturate with high SPL sources. Therefore there is still a need for different sensitivity lavalier microphones.

Is the Bluetooth connection being used to remotely control the gain of the transmitter?

No, there is no remote control of the gain circuitry at all. There are two advantages to this over a system which does perform remote gain control of the transmitter: a) if the transmitter is out of range of Bluetooth/remote control, the gain can still be controlled by the mixer; b) the gain can be controlled as quickly as you can move the trim knob.

Can I use a non-Sound Devices mixer and get the benefits of GainForward?

Yes, the A20-Mini and A10-RX can be used with virtually any brand of mixer. Use the gain control, low-cut, and limiter built into the A10-RX’s menu to control these functions.

Can I come out of the A10-RX via the analog output and still get the benefits of the GainForward architecture?

Yes, provided you use the gain control provided on the A10-RX itself.

Does the AES output of the A10-RX have enough dynamic range for GainForward?

Yes, AES can transport 144 dB of the audio’s dynamic range, so it is definitely sufficient for the >130 dB of dynamic range of the lav microphone.

On the A20-Remote app, I notice a “License” icon near the frequency I have set. What is this?

This icon is a friendly reminder that you legally need a license from your local government to operate on this frequency.

I notice that the green audio LED glows with audio no matter what the GainForward gain is set to. Why doesn’t the brightness of the LED change?

The green audio LED on the A20-Mini is a very wide dynamic range indicator and thus indicates the entire dynamic range of the microphone. It is designed *not* to change with any gain settings. This indicator is used for a quick visual indicator that the microphone is working.

When is simultaneous record and transmitting available on the A20-Mini?

A20-Mini transmitters purchased in the United States of America do not have a simultaneous record and transmit (REC + RF) mode.
A20-Mini transmitters purchased outside the United States of America have a REC + RF mode. This mode is available when operating outside of the United States.
REC + RF mode is not available on any A20-Mini while operating in the United States.

How robust is the plastic chassis?

The A20-Mini’s chassis has an exceptionally high strength-to-weight ratio thanks to its aluminum/high-strength Ultem thermoplastic construction. Additionally, each piece of the chassis is curved in both directions, imparting a very stiff geometry. All together, the chassis feels very light, but extremely solid.[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column]


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