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Adastra AT20-100VR 20W 100V Volume Control Attenuator with 24V Relay

by Adastra
SKU 952.463
Sold out
Original price £22.99 (inc. VAT) - Original price £22.99 (inc. VAT)
Original price £22.99 (inc. VAT)
£22.99 (inc. VAT)
£22.99 (inc. VAT) - £22.99 (inc. VAT)
Current price £22.99 (inc. VAT)

The Adastra AT20-100VR is a 20W 100V Line Wall-Mount Volume Control with an 11-position rotary switch providing up to 33dB of attenuation in 3dB steps and a 24V relay for automatic bypass to full volume when triggered from a fire alarm panel — supplied with a surface mount back box.

The Adastra AT20-100VR is a wall-mount 100V line attenuator designed for controlling output volume at individual speaker zones in distributed 100V public address and background music installations — handling up to 20W of 100V line audio for slightly larger speaker loads than the AT10-100VR. A large rotary switch with 11 positions provides accurate, stepped volume control with 3dB attenuation per step — up to 33dB total — for precise and consistent level adjustment at each zone location.

The built-in 24V relay automatically bypasses the attenuator to full volume when triggered from a fire alarm panel or emergency system, ensuring emergency announcements are always broadcast at full level regardless of the local volume setting. Supplied with a surface mount back box, the AT20-100VR can also be fitted into a standard flush-mount pattress box with a minimum internal depth of 47mm.

Adastra AT20-100VR Key Features:

  • 20W 100V Line Attenuator: For controlling speaker volume in 100V distributed audio systems.
  • 11-Position Rotary Switch: 3dB attenuation per step — up to 33dB total attenuation for precise volume control.
  • 24V Relay Emergency Bypass: Automatically overrides to full volume when triggered from a fire alarm panel.
  • Surface Mount Back Box Included: Ready to install straight out of the box.
  • Flush Mount Compatible: Fits standard pattress box with minimum 47mm internal depth.
  • Screw Terminal Connections: In, Out and Relay +/- for clean, professional installation wiring.

Read Now - How to control the volume of your 100V line audio system

      Specifications:

      • Power Handling (Max): 20W
      • Graduation: 11-position x 3dB (up to 33dB attenuation)
      • Emergency Control: 24V bypass to full level
      • Connections: In, Out, Relay +/- screw terminals
      • Mounting Depth: 47mm minimum
      • Dimensions: 86 x 86 x 70mm
      • Weight: 246g

      Adastra - Commercial Amplifiers & Speakers

      Adastra has been providing audio equipment since 1949, with a focus has always on practical, affordable, and installer-friendly design.

      Their range covers the full scope of what a commercial installation demands, from zoned background music and public address through to noise pollution control and induction loop systems. Hardware includes speakers, amplifiers, mixers, cable and everything inbetween.

      Adastra sits naturally alongside what we do at Audio Volt. Their products are built for real-world commercial environments, priced accessibly, and backed by decades of industry presence, making them a solid choice whether you are specifying a simple background system or something more involved.

      View the Adastra range here

      View our shipping and delivery information below. All prices include VAT.

      Important notice for non-UK orders: Any order being shipping outside of the UK will incur an import tax. See below for more information.

      Cut-off Times

      Orders must be placed before 3:30pm to guarantee same-day dispatch. Any orders placed after this time are not guaranteed to be shipped the same day, and are more likely to be shipped the next working day.

      To guarantee Saturday Delivery, orders must ideally be placed before 2pm.

      We operate during office hours, Mon-Fri, 9am - 5pm, and are closed during the weekend.

      Orders placed over the weekend or Friday after cut-off will be processed and shipped the following Monday (or Tuesday during bank holidays).

      Mainland UK Delivery Charges

      Standard delivery
      Standard delivery
      Orders under £99
      2-3 working days (Mon-Fri) £3.99
      Standard delivery
      Orders £99 and over
      2-3 working days (Mon-Fri) Free
      Express delivery
      Next-day delivery
      All orders
      Next working day (Mon-Fri) £9.95
      Next-day pre-12
      All orders
      Next working day, by 12pm (Mon-Fri) £14.99
      Next-day pre-10:30
      All orders
      Next working day, by 10:30am (Mon-Fri) £34.99
      Saturday delivery
      All orders
      Saturday £19.99

      Note: Next-day services are classed as working days (Mon-Fri) and do not include weekends. Please choose Saturday delivery if you require the item over the weekend.

      Please also note orders with a high number of boxes may be subject to an additional charge.

      All delivery options will be available at the checkout stage. Please ensure you add a mobile number to your order for tracking information.

      Offshore & International

      We ship to Scottish Highlands, Islands, Ireland and the EU. Please see the table below for base prices. Please note that these prices are subject to change based on the number of boxes.

      UK offshore & remote
      Scottish Highlands & Islands
      Standard
      2-3 days (Mon-Fri) £3.99 under £99
      Scottish Highlands & Islands
      Next-day
      Next working day (Mon-Fri) From £59.99
      Northern Ireland
      Standard
      2-3 days (Mon-Fri) £3.99 under £99
      Northern Ireland
      Next-day
      Next working day (Mon-Fri) From £59.99
      Isle of Man
      2-3 days (Mon-Fri) From £29.99
      Channel Islands
      Jersey & Guernsey
      2-3 days (Mon-Fri) From £29.99
      International
      Republic of Ireland
      2-3 days (Mon-Fri) From £29.99
      EU
      Variable based on country From £29.99

      The following postcodes fall under 'Highlands & Islands', and are subject to the above rates/lead time.

      • Scottish Highlands: FK17-21, IV1-39, IV52-54, IV63, KW1-14, PA21-40 (excluding PA38), PH19-26, PH30-41, PH49-50
      • Scottish Islands: HS1-9, IV40-51, IV55-56, KA27-28, KW15-17, PA20, PA38, PA41-49, PA60-78, PH42-44, ZE1-3

      If a UK Mainland next-day service is selected at checkout, please be aware that it won't be sent on that service.

      If you require a next-day service to Northern Ireland and the highlands, get in touch so we can assist further.

      EU Import Tax

      Any goods shipped outside of the UK, over a certain value, will incur an import tax. The cost and rate will depend on the country and the order value.

      This is a legal requirement and MUST be paid prior to delivery in order to receive your goods. You will be contacted by the courier once the order is dispatched to pay the fee.

      Failure to pay import tax when applicable will result in the order being shipped back to Audio Volt. Any returned goods sent back to us due to non-payment of import tax are NOT ELIGIBLE for a refund on the shipping charge.

      You can obtain an import duty estimate here.

      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 email info@audiovolt.co.uk). We will then send you an RMA number and a 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 assume 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 72 hours 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.

      Any Questions?

      If you have any questions about our returns policy, please telephone us on 02476 369890 or email us at info@audiovolt.co.uk.

      We operate during office hours, Mon-Fri, 9am - 5pm, and are closed during the weekend.

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