A-20 Mini radio transmitter

Small in size. Big on features. A20-Mini.



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. The A20-Mini’s high-efficiency internal 2.4 GHz antenna ensures excellent Bluetooth range.


With the Mini’s GainForward Architecture, easily set the transmitter’s gain, low-cut, and limiter directly on your 8-Series.1

For a full explanation of the A20-Mini’s GainForward Architecture, read this article. https://www.sounddevices.com/gainforward-explained/ 

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.2

A detailed article on the benefits and architecture behind 32-bit float is available here. https://www.sounddevices.com/a20-mini-32-bit-float-recording/ 


Built-in 64 GB media.

No more SD card management – the ample-sized media stores more than 80 hours of continuous, uncompressed 48 kHz, 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.

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).

Discover the Mini.

Browse our video library.


A20-Mini FAQ

Last updated July 21, 2021

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.




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

8 k 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)



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