Digital Wireless Transmitter


Sound Devices’ first miniature transmitter incorporates state-of-the-art features such as full remote control via the A20-Remote app, GainForward Architecture, internal 32-bit float recording, a worldwide tuning range of 470 MHz – 694 MHz, and more. The A20-Mini is fully compatible with Sound Devices’ existing A10 Digital Wireless System.

  • Full remote control of the Mini via A20-Remote companion app. Control frequency and RF power, turn the Mini on and off, start and stop recording, mute the microphone, format the media, view the status of all your Minis, and more.
  • GainForward Architecture: set the Mini’s gain levels via trim control (with an 8-Series) or at the A10-RX (other mixers).
  • Full 10 Hz – 20 kHz audio bandwidth; 100% digital RF modulation and transmission. Same excellent range and audio quality as the A10-TX.
  • Worldwide tuning range of 470 MHz – 694 MHz.
  • Built-in 32-bit float, 48 kHz recorder with 64 GB storage for over 80 hours of record time.
  • Offload recorded WAV files via USB-C and optionally conform/convert with SD-Utility.
  • Powering via AAA or NP-BX1 (Li-Ion) with built-in charging for NP-BX1 Li-Ion battery.
  • Internal supercapacitor-powered timecode generator can be jammed via USB-C.
  • Water-resistant with a rounded form factor.


The A20-Mini digital wireless transmitter combines legendary British audio quality with the best of American design. The sleek, rounded form fits perfectly into body contours and underneath tight clothing.

…and control.

Control the A20-Mini from your phone or tablet via Bluetooth 5.2 with companion app A20-Remote. Set frequency and RF power, turn the Mini on and off, start and stop recording, mute the microphone, format the media, view the status of all your Minis, and more. The A20-Mini’s high-efficiency internal 2.4 GHz antenna ensures excellent Bluetooth range.

Group Powering and Recording.

All transmitters can be powered up and down simultaneously or made to start and stop recording with a single tap from your smartphone or tablet. Use A20-Remote to create custom groups with selected transmitters or use an automatically-created all-transmitter group.


With the Mini’s GainForward Architecture, easily set the Mini’s gain, low-cut, and limiter directly on your 8-Series. This immediate, local control of gain allows quick adaptation to changing volume levels and saves time during production.

32-bit float recording.

The A20-Mini records in 32-bit float for an astounding >130 dB of dynamic range. This allows for audio gain decisions to be made after recording, with zero loss in headroom or noise performance.

Built-in 64 GB media.

No more SD card management – the ample-sized media stores more than 80 hours of continuous, uncompressed 32-bit float recording. Simply offload the recorded WAV files via the high-speed USB-C port to a computer.

Never lose time.

The Mini’s ultra-accurate 0.2 ppm internal timecode generator can be jammed via USB-C with negligible drift over a 24-hour period.

Flexible, worldwide operation.

With a built-in 470 MHz to 694 MHz UHF tuning range, your Mini can go wherever work takes you.

Power away.

Use off-the-shelf rechargeable or AAA batteries – no adapter needed. 3 AAA batteries or a rechargeable Sony NP-BX1 give you the ultimate in powering flexibility. You can even recharge the NP-BX1 via the Mini’s USB-C.


With its extensive gasketing and waterproof connectors, the A20-Mini can easily withstand water and sweat.


Optional accessory provides easy battery charging, file transfer, and timecode jamming of up to eight A20-Minis at a time. Powered via DC (TA4) or USB-C (USB-PD).


Click on each group to expand. Specifications are subject to change without prior notice.

Frequency Range
  • 470 to 694 MHz
  • Transmitters are tunable in 25 kHz steps
  • Available frequencies are dependent on region
RF Output Power
  • Off, Low – 2 mW, Normal – 10 mW, High – 20 mW, Max – 40 mW, selectable 
Modulation Mode
  • Sound Devices proprietary digital RF modulation 
  • UHF RF: SMA connector, removable 
  • 2.4 GHz built-in 
Audio Frequency Response
  • 10 Hz – 20 kHz, +/- 1 dB re 1 kHz 
Audio Input Type 
  • Lavalier Microphone via 3-pin LEMO 
  • Pin-1 ground 
  • Pin-2 5 V bias 
  • Pin-3 audio/bias (8k ohm to 5 V) 
Bias Power
  • 5 V
Input Impedance
  • 8k ohms 
Input Clipping Level
  • +5 dBu 
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
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 (LTC)
  • Input via XL-TC-USBC-LEMO or XL-TC-USBC-BNC: 0.3 V – 3 V p-p (–17 dBu to +3 dBu), 20k ohm impedance
  • 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 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)
  • 75.8 mm x 48 mm x 19 mm 
  • 2.98 in x 1.88 in x 0.74 in 
  • 51 g (without batteries) 
  • 1.8 oz (without batteries)


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.

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.

Why is the A20-Mini branded as Sound Devices and not Audio Ltd?

Sound Devices and Audio Ltd got married back in 2018. Though we both speak (more or less) the same language, we live in two different houses. Now you get both wonderful groups under one simple name, Sound Devices.

How many groups can I make in A20-Remote?

You can make one custom group with any transmitters you select. There is also an automatically-created “All Transmitters” group.


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.

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.

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.
When sending analog audio from the A10-RX, use the A10-RX Input menu to control gain, low cut, and limiter.
When sending AES audio from the A10-RX, allow the third-party mixer full control of gain, low cut, and limiter. When in this configuration, set the A10-RX Input menus as follows:

  • Gain = 0 dB
  • Low Cut = Off
  • Limiter = Off

I’m using a 688 with no SL-6. Can I still get the benefits of GainForward?

You can still get all the benefits of GainForward in the 688 without the SL-6 provided you use the 688’s digital inputs and set the A10-RX to unity gain (0dB). Then simply adjust the digital trim gain on the 688. Full dynamic range, and zero lag A20-Mini level adjustments.

I’m using an A10-Rack with my 8-Series. Can I still get the benefits of GainForward?

You can still get all the benefits of GainForward provided you connect from the A10-Rack to the 8-Series via Dante or AES. Set the A10-RXs to unity gain (0 dB), then dynamically adjust the received A20-Mini signal level using the digital trim gain on the 8-series. Full dynamic range, and zero lag A20-Mini level adjustments.

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.


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Latest Firmware: A20-Mini Firmware v2.00
Released: October 11, 2021

Note: To ensure best performance, always run the latest version of A20-Mini firmware with the latest version of A20-Remote. 


  • Support for A20-Remote group powering and recording. Allows for control of power on, power off, record, and stop of all transmitters or custom groups.
  • New “LEDs” menu via A20-Remote. Provides options for turning the A20-Mini LEDs on and off. 
  • New “Resume record state upon powering on” option via A20-Remote. When active, the A20-Mini automatically resumes recording if the transmitter was recording when last powered down.


  • Jamming timecode while in record mode now begins a new WAV file stamped with the jammed timecode value.  


  • Fixed issue where batteries could drain when A20-Mini was left connected to a timecode source or a powered off PowerStation-8M. 
  • All A20-Mini transmitters inserted in a PowerStation-8M now reliably mount as mass storage devices to a computer. 
  • Fixed issues where timecode could get out of sync.
  • Rare events where A20-Mini goes unresponsive after disconnecting USB-C without first ejecting from the computer no longer occur.

A20-Remote APK for Android

A20-Mini Compliance