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Adastra A4 - 4 Channel Stereo PA Amplifier, 4 x 200W, 4 Ohm with Bluetooth

by Adastra
£174.99 (inc. VAT)
SKU 953.404

The Adastra A4 4 Channel Stereo Amplifier is a great choice for small Cafes, Offices, Restaurants & shops looking to install a background music sound system. The amplifier offers 2 zones across 4 channels each with independent volume adjustment, allowing for complete control across the whole system.

4 x channels at a minimum of 4 ohms allow for a large variety of speakers to be connected. Each channel has individual volume control and an LED signal indicator.

Where the Adastra A4 shines is its zonal capabilities. Channel 1/2 & 3/4 are split into groups with further control. Each pair of channels has EQ control, and source selection meaning different audio sources can be played on each pair of channels.

There are 3x stereo inputs, 2x RCA and an L & R 1/4" (6.35mm) Jack, and 2x Mono 1/4" (6.35mm) Jack inputs, indicated as Mic 1 and Mic 2.

There is also a stereo RCA line out, which can be used to expand the system as this will allow you to send the input source to another amplifier, or compatible active sub.

An inbuilt media player section offers playback of mp3 audio tracks from USB drive or SD card and also has a Bluetooth receiver and FM radio tuner.


  • Independent stereo playback to 2 separate zones
  • Media player with USB/SD playback
  • FM radio tuner with external aerial connection
  • Bluetooth receiver


Read our blog post about the best amp for restaurants

      If you require any further assistance regarding our background music systems, just contact us on 02476 369890 and one of our experts will be happy to help.

      See SPECIFICATION tab for technical specs



      Power supply: 230Vac, 50Hz (IEC)
      F5A, 250V
      Output power rms @ 4 Ohms:
      4 x 200W
      Output power rms @ 8 Ohms:
      4 x 100W
      Amplifier construction:
      Class D
      Frequency response:
      20Hz - 20kHz ±0.5dB
      Microphone inputs:
      2 x 6.3mm jack (mono)
      Line inputs Line 1:
      L+R (6.3mm jack/RCA), Line 2: L+R (RCA)
      Auxiliary input:
      3.5mm stereo jack
      Audio source:
      USB/SD mp3 playback, FM tuner, BT receiver
      Input controls:
      Aux, Media, Line1, Line2, Mic1, Mic2, Talkover
      Line output:
      4 x RCA
      Antenna connection:
      F type (FM tuner)
      Output controls:
      2 x source select, 2x Bass, 2x Treble, Ch1, Ch2, Ch3, Ch4
      482 x 240 x 88mm



       Download the user manual HERE



      View all Adastra 100v Line products by Audio Volt

      For over 60 years Adastra has serviced the needs of the background audio market as a fully established brand name, celebrated for quality and excellence, and they continue to develop their range in order to remain at the forefront of the industry.

      Founded in 1949, Adastra has earned a great reputation for delivering high-quality background audio systems.

      Their products have been created with you the user in mind, offering a flexible and modular approach to installation of music background systems.

      With a comprehensive range of associated products also available, including speaker brackets, rack cabinets and microphones.  You can see why Audio Volt and Adastra are a match made in heaven. 



      Delivery Charges

      Orders over £50.00 will be delivered FREE of charge via our Standard UK Delivery Service (2-3 days, UK Mainland).

      All orders below £50.00 will be sent at a rate of £3.99 per order (2-3 days, UK Mainland). 
      If you need your item faster we also offer a Premium Delivery, Next Day Tracked service at a cost of £9.95.

      Do you require your item before 12 pm? We offer a Premium Delivery, Next Day Tracked, Pre 12 service at a cost of £24.95.

      All delivery options will be available at the delivery stage in the checkout. 

      (Please ensure you add a mobile number to your order for tracking)

      European Delivery Charges

      Standard EU Shipping service £16.99  (Shipping to France, Germany, Ireland, Guernsey & Jersey - 2-4 days)


      Delivery Notes

      On delivery you must inspect the goods carefully for damage as Audio Volt is unable to accept responsibility for damage in transit, shortage of delivery or loss of products unless the customer advises Audio Volt of such within three working days from the date of delivery.

      60 Day Returns Policy

      We ask that you follow these guidelines to help us process your return as quickly and efficiently as possible:

      1. Please keep your order reference to hand. This confirms your original order and gives us the necessary details to authorise the product’s return.

      2. Contact our Customer Services Team on 02476 369890 (or e-mail We will then send you an RMA number and returns form which needs to be completed and sent back with the returned item(s).

      3. (If the order has been unpacked) re-package it to ensure that it is being returned in its original condition. Please make sure all items relating to the product are returned, including manuals and cables.

      4. When returning an item please obtain a ‘proof of postage’ receipt from the Courier.

      Returned items must be mailed within 10 days of when the RMA Number has been issued. Items received with a post date 30 days after your requested return will NOT be eligible for refund.

      Please note: Our returns policy is quite straightforward but there are a number of conditions that we ask our customers to comply with before applying:

      1. It is your responsibility to request a return. If you don’t tell us you want to make a return, we don’t know. Once you do tell us, we will do everything we can to action it.

      2. If you have not requested a return within 60 days of receiving an order, we will have assumed that you are intending to keep it and we will not authorise a return.

      3. We always refund the payment according to how the original purchase was made and aim to do so within 72hrs of the return being received by us.

      4. Returned goods are liable for a restocking fee of 15% towards handling and repackaging if the order is not returned in its original, unopened packaging. This charge will be subject to our inspection of the returned goods.

      5. Delivery charges will not be refunded unless the delivered goods are faulty.

      6. Replacement products are dispatched immediately after the returned goods have been received and accepted by Audio Volt.

      7. Items that develop a fault within 30 days of delivery are eligible for a replacement or a refund. Delivery costs are also reimbursed for faulty items. Please contact our Customer Services Team on 02476 369890 if you believe your item has developed a fault.

      Finally, please remember that notifying us of your intention to apply for a return, saving the delivery paperwork and keeping the order in its original packaging will help both you and Audio Volt to process the return quickly.

      If you have any questions about our Returns policy please telephone us on 02476 369890 or email us at