Indigo frame systemDual channel symbol


What is it?

AADA-STM-1 stereo to mono distribution amplifierDual channel stereo to mono audio distribution amplifier.

Reason to choose it...

It can be configured in three different input/output configurations, and provides up to 16 mono outputs – with individually balanced floating outputs and useful features such as audio gain adjustment and audio silence detectors.

Ideal for...

Any applications where you need to convert stereo analogue audio to mono – and require lots of outputs. See who's using it.

Got a question?

We would be very happy to answer any questions you've got about the AADA-STM-1. Either send us an e-mail or get an immediate response by speaking to us now on our Live Chat...

  • Main features
  • Details
  • Specs
  • What outputs do I get?
  • What do I order?
  • Who's using it?

Main features

  • Stereo to mono audio distribution amplifier
  • Flexible inputs and outputs - configure it as dual or single channel amplifier
  • When configured as single channel amplifier: one stereo input and 16 mono outputs
  • Two configurations available when dual channel amplifier: either two stereo inputs with eight mono outputs per channel, or two stereo inputs with four stereo outputs of the first channel and 12 mono outputs of the second
  • Low noise and distortion
  • Robust fully floating inputs and outputs
  • Excellent isolation between outputs with individual line drivers
  • Audio gain adjustment from +12dB to -12dB
  • Audio silence detector for each output audio group
  • Overvoltage detector for each output audio group
  • Headphone monitoring of all channels
  • Inputs and outputs accessed by using an appropriate rear module (RM17)
  • Housed in Indigo rack frames
  • Space-saving: 100mm x 266mm module allows 12 AADA-STM-1 in 2U (six in 1U and two in desk top box)
  • Ideal for cost-sensitive applications with manual control (board edge switches)
  • Five year warranty (with product registration)
  • This product is available to either purchase or hire, with hire pricing typically 6% of list price per week (with one week minimum hire period and £200 minimum charge)


Convert stereo audio to mono

The AADA-STM-1 is a stereo to mono distribution amplifier, with three different configuration modes allowing the flexible conversion and distribution of analogue audio in any broadcast environment.

Configure the inputs and outputs to be what you need

The AADA-STM-1 can be configured as either a single channel amplifier or a dual channel amplifier.

When configured as a single channel amplifier, it provides one stereo input and 16 mono outputs. When configured as a dual channel amplifier, two configurations are available: either two stereo inputs with eight mono outputs per channel, or two stereo inputs with four mono outputs of the first channel and 12 mono outputs of the second.

Guarantee robust outputs

The AADA-STM-1 has the essential low noise and distortion which allows the audio to pass through more stages of processing without a loss in quality.

The balanced outputs are fully floating which makes them very robust - should one side be connected to ground, the other will double in amplitude to maintain the difference between the balanced signals, giving a correct single-ended system.

Each output has an individual line driver which gives excellent isolation between them, meaning a damaged signal injected on to one of the outputs will not affect any of the others.

Adjust the gain

The AADA-STM-1 can deal with analogue audio that comes from anywhere, with the ability to be configured for the different maximum operating levels that can occur over different geographical areas.

The fixed gain settings (0dB or +6dB) allow you to scale the incoming audio so that it is the same relationship to your full scale level. The variable gain settings (of +/-3dB) then allow you to correct for gain errors elsewhere.

Monitor your audio

A number of useful monitoring tools ensure you remain aware of exactly what's happening to your audio at all times.

Each output audio group has an individual audio silence detector with adjustable threshold level and duration - useful for alerting you that your audio signal has failed. There is also an overvoltage detector for each channel with adjustable threshold level. Both these tools can be used with GPIs to trigger alarms.

Two 3.5mm jacks are provided for local monitoring using headphones and can be used during installation or when investigating problems, allowing you to listen to the audio at various stages to check for continuity or quality.

Easy to set up and use

It takes no time at all to get the AADA-STM-1 configured and on air. The manual AADA-STM-1 is operated by on-board pots and jumper links.

Save rack space

Crystal Vision frameThe AADA-STM-1 will save you rack space, with this 100mm x 266mm module providing up to 24 stereo to mono DAs in a single 2U frame, making it excellent value per channel.

The AADA-STM-1 conveniently fits in Crystal Vision's Indigo frames (available in three sizes to suit all applications) alongside any other video or audio products from the Indigo range.

The audio inputs and outputs are accessed by using the RM17 frame rear module.




Standard Crystal Vision module 266mm x 100mm

Weight: 175g

Power consumption: 8 Watts


Four stereo, electronically balanced

High impedance input (>20 kohm)

Maximum level: +28dBu

Factory set default: +24dBu


16 (four per channel), electronically balanced, using RM17 frame rear module

Low impedance outputs: 66 ohm

Maximum level: +25dBu

Factory set default: 0dBFS = +24dBu

Loading: Maximum of only four outputs (one per group) into 600 ohm; maximum of 16 outputs into >10 kohm


Three configuration modes are available:

Channel 1: one stereo input and eight mono outputs; Channel 2: one stereo input and eight mono outputs

Channel 1: one stereo input and 12 mono outputs; Channel 2: one stereo input and four mono outputs

Channel 1: one stereo input and 16 mono outputs


Total Adjustment -3dB to +9dB

Continuous adjustment: +/-3dB using multiturn pot adjustment

Link adjustment: +6dB, 0dB (on board link settings)


Signal to noise ratio: >106dB, 0dB gain, 0dBFS = +24dBu;  >104dB, 0dB gain, 0dBFS = +18dBu

Frequency response: +/-0.05dB (20Hz to 20kHz)

Total Harmonic Distortion (THD) and noise: <0.003% at 1kHz, +18dBu/+24dBu

Common mode rejection: >74dB (20Hz to 20kHz)

Interchannel crosstalk: <-94dB, 10kHz


Four (one per output audio group)

Set period of silence before indication from one to 120 seconds in eight second increments

Set silence threshold between -18dBu and -42dBu (factory default set to -30dBu)


Four (one per output audio group)

Set overvoltage threshold between +6dBu and +25dBu (factory default set to +25dBu)


Two stereo (four mono) via two 3.5mm stereo jack sockets

Output level: 0dBFS = +10dBu


Active pull to ground, pulled up to +5V through 10 kohm


Two GPI inputs select silence or overvoltage or both indications on GPI outputs


Electrically: Open collector transistors 30V, 330 ohm current limit resistors, 10mA max


Four GPI outputs indicate silence/overvoltage status per group


Four LEDs (one per group) to indicate silence/overvoltage status

Two LEDs to indicate power supply status


Power rail monitoring, channel gain adjustment, silence threshold, silence time and overvoltage level set by switches at board edge


What outputs do I get?

Signal inputs and outputs are accessed by using an appropriate rear module.

The Indigo rear modules slot on to the back of the frame and typically feature BNC, D-Type, RJ45 and optical connectors. The single and double slot rear modules can be used with all three frame sizes, while the quad slot rear modules just fit the 2U frames.

There is one rear module available for the AADA-STM-1...

RM17 rear module label and connections

More about the RM17

Connectors: 44-way high density D-Type and 15-way standard density D-Type

Frame slots used: 1

Boards in 2U: 12

Boards in 1U: 6

Boards in desk top box: 2

Why use it: If you prefer D-Types to DIN connectors

Also used for: AADA416FM and AADA416FR

Real RM17 rear module

RM17 rear module label for AADA-STM-1

AADA-STM-1 inputs and outputs with RM17 rear module


For more visual technical information, download the AADA-STM-1 block diagram.

What do I order?

Request a quote...

Read the ordering info below then fill in this form to request a quote for the AADA-STM-1 stereo to mono DA and accessories...

Your contact details
Items for quote

First you need the 100mm x 266mm module...

Stereo to mono distribution amplifier

Next choose your frame size and power supplies - from 2U to desk top box...

Indigo 2SE
CoolFlow 2U frame with power supply redundancy and active front panel featuring smart CPU for up to 12 Crystal Vision modules. Allows Ethernet connection to a PC
Indigo 1AE-DP
1U frame with power supply redundancy and active front panel featuring smart CPU and integrated control panel for up to six Crystal Vision modules. Includes two fixed PS-80i power supplies. Allows Ethernet connection to a PC
Indigo 1SE-DP
1U frame with power supply redundancy and active front panel featuring smart CPU for up to six Crystal Vision modules. Includes two fixed PS-80i power supplies. Allows Ethernet connection to a PC
Indigo DT
Desk top box with passive front panel for up to two Crystal Vision modules. Includes fixed power supply
Indigo DTSE
Desk top box with active front panel featuring smart CPU for up to two Crystal Vision modules. Includes fixed power supply. Allows Ethernet connection to a PC
160 Watts power supply for Indigo 2SE frame. Requires either one PSU-160i (no redundancy) or two PSU-160i if power supply redundancy is required

You need a rear module to access your inputs and outputs...

Single slot frame rear module. Allows maximum number of AADA-STM-1 in frame (12 in 2U, six in 1U, two in desk top box). Gives access to all audio inputs and outputs

The AADA-STM-1 is controlled by board edge switches - therefore you will not require a control panel or PC software.


Who's using it?

Users of the AADA analogue audio distribution amplifiers include...

  • 4KXL (UK)
  • Advanced Broadcast Services (UK)
  • Advanced System Integrated Co., Ltd. (Taiwan)
  • Advent Communications (UK)
  • Al Jazeera (Qatar)
  • Alter Ego Media S.A. (Greece)
  • Antenna Hungária (Hungary)
  • Antenna TV (Greece)
  • ANTV (Vietnam)
  • Arabsat (Saudi Arabia)
  • Arqiva (UK)
  • Astro (Poland)
  • AVC (UK)
  • Bắc Ninh TV (Vietnam)
  • Bath Spa University (UK)
  • BBC (UK)
  • BBC Millbank (UK)
  • BBC Northern Ireland (UK)
  • BBC Scotland (UK)
  • BBC Studioworks (UK)
  • BBC Wales (UK)
  • BBC World Service (UK)
  • BFE Studio (Austria)
  • Binh Phuoc TV (Vietnam)
  • Channel 4 (UK)
  • Channel 9 (Greece)
  • Channel 10 (Greece)
  • Channels TV (Nigeria)
  • Chatham House – The Royal Institute of International Affairs (UK)
  • Chicopee Telecom (USA)
  • Chiyoda-Video (Japan)
  • Chukyo TV Broadcasting (Japan)
  • City of Glasgow College (UK)
  • City University London (UK)
  • Comux (UK)
  • Coronation Street/ITV Studios (UK)
  • Cotswold Communications (UK)
  • Covetel (Venezuela)
  • Crete TV (Greece)
  • Custom Consoles (UK)
  • CVP (UK)
  • Czech TV (Czech Republic)
  • dB Broadcast (UK)
  • Dega Broadcast Systems (UK)
  • DigitalWide srl (Italy)
  • Doordarshan Kendra (India)
  • E to E (UK)
  • Eddystone Broadcast (UK)
  • EDI Effetti Digitali Italiani Srl (Italy)
  • Emmerdale/ITV Studios (UK)
  • EMMRC - Educational Multimedia Research Centre (India)
  • EMS (UK)
  • Encore Broadcast Solutions (USA)
  • ERT (Greece)
  • ESPN Star Sports/Fox Sports (Singapore)
  • ETI-Electronic Technology Inc. (USA)
  • Euronews (Albania)
  • Eurosport (Greece)
  • FAL Systems (UK)
  • FB TV (Turkey)
  • Foss Productions (Greece)
  • Fountain Studios (UK)
  • Gee Broadcast Systems (UK)
  • Gems TV (India)
  • Gibraltar Broadcasting Corporation (Gibraltar)
  • Giga-Com (UK)
  • GigaSat (UK)
  • Global (UK)
  • GMTV (UK)
  • Habertürk TV (Turkey)
  • Hai Duong Radio and Television Station (Vietnam)
  • Hangzhou Justtong Network Technology inc.,Ltd. (China)
  • Hangzhou TV (China)
  • Hayfisher Productions (UK)
  • HB Communications (USA)
  • HD Vietnam (Vietnam)
  • Hollyoaks/Lime Pictures (UK)
  • Houses of Parliament (UK)
  • HTV - Ho Chi Minh City Television (Vietnam)
  • Ideal Shopping Direct (UK)
  • INA TV (Greece)
  • Indira Ghandi National Open University (India)
  • International Criminal Court (Netherlands)
  • ITV (UK)
  • ITV Studios (UK)
  • Jewellery Maker (UK)
  • JKS Inc. (USA)
  • Kapa Studios (Greece)
  • King Khalid University Medical City (Saudi Arabia)
  • Kingsway International Christian Centre (UK)
  • Kontra (Greece)
  • KT - Korean Telecom Media (South Korea)
  • Links Broadcast (UK)
  • Manchester Studios (UK)
  • Media Broadcast Technology (Vietnam)
  • Mediaspec (UK)
  • Medialogy Engineers Ltd. (UK)
  • Megahertz Broadcast Systems (UK)
  • MEGA TV (Cyprus)
  • MEGA TV (Greece)
  • Molinare (UK)
  • MTV (Greece)
  • National Assembly for Wales (UK)
  • National Performing Arts Center (Taiwan)
  • News 24 (Albania)
  • Nova TV (Bulgaria)
  • OneSource Distributors LLC (USA)
  • Open TV (Greece)
  • ORF (Austria)
  • Oxford Sound & Media (UK)
  • Pinellas County Schools (USA)
  • PLD Production (Greece)
  • Prodigy Enterprises Inc. (China)
  • Puls 4 (Austria)
  • Radio Televisyen Malaysia (Malaysia)
  • Reality TV Channel (Greece)
  • Royal College of Music (UK)
  • Royal Opera House (UK)
  • RTC Télé Liège (Belgium)
  • RTÉ (Ireland)
  • RTVS (Slovakia)
  • Russia Today – London Bureau (UK)
  • Sat-Comm (UK)
  • Scottish Parliament (UK)
  • SEC - Supreme Education Council (Qatar)
  • Show TV (Turkey)
  • Siemens (UK)
  • Smart TV (UK)
  • Soc Trang TV (Vietnam)
  • Studios A/S (Denmark)
  • STV (Spain)
  • STV (UK)
  • Supersonic TV (Albania)
  • Supersport (South Africa)
  • SZTV - Szombathelyi Televízió (Hungary)
  • TBS (Taiwan)
  • TCS Telecom e Serv. Srl (Italy)
  • Tele Bruxelles (Belgium)
  • Telecentras (Lithuania)
  • Telemedia (South Africa)
  • Télésambre (Belgium)
  • TeleStudio Modena (Italy)
  • Teletech (Japan)
  • Teltechco (Vietnam)
  • Televideo (UK)
  • Telewave (Greece)
  • Thameside (UK)
  • The ADI Group (UK)
  • The Federation of Small Businesses (UK)
  • The Jewellery Channel (UK)
  • The Military Broadcasting Centre (Vietnam)
  • The One Show (UK)
  • TJC (UK)
  • Toshiba (UK)
  • TP Emitel (Poland)
  • TRT (Turkey)
  • Türkmeneli Televizyonu (Turkey)
  • TV AlHijrah (Malaysia)
  • TV Globo (Brazil)
  • TV 2 (Denmark)
  • TV 360 (Turkey)
  • TVP (Poland)
  • TV Skyline (Germany)
  • TVT – Television Versioning & Translation Ltd. (UK)
  • UBE Service (UK)
  • United Broadcast & Media Solutions LLC (UAE)
  • Universal Media Services (USA)
  • University of Central Florida (USA)
  • University of Essex (UK)
  • University of York (UK)
  • Videocation (Germany)
  • Viettel TV (Vietnam)
  • Vinh Long Radio and Television (Vietnam)
  • Vinh Phúc TV (Vietnam)
  • Vislink Broadcast (UK)
  • VSC Design (UK)
  • VTC (Vietnam)
  • VTV5 (Vietnam)
  • Westminster Live (UK)
  • William Hill (UK)
  • WTS Broadcast (UK)
  • Wyre Broadcast Solutions (UK)

Do more...


Explore more...

Audio distribution

From the Indigo frame system...

  • AADA416FM analogue audio distribution amplifier with manual control
  • AADA416FR analogue audio distribution amplifier with remote control
  • DADA208 reclocking digital audio distribution amplifier
  • DADA208N non-reclocking digital audio distribution amplifier
  • DADA208D digital audio delay and distribution amplifier
  • MADDA105 MADI audio distribution amplifier with five outputs
  • MADDA111 MADI audio distribution amplifier with eleven outputs

From the Vision frame system...

  • AADA-VF analogue audio distribution amplifier
  • DADA-VF digital audio distribution amplifier
  • 3GDA-VF MADI audio distribution amplifier with 12 outputs

Not sure which audio DA is best for your application? Have a look at our Indigo and Vision audio distribution amplifiers comparison chart to help you make a decision...