Adastra MM321 Bluetooth Rack Mixer with USB & FM Player & multiple XLR / RCA inputs
The Adastra MM321 is a versatile 19" rack-mount pre-amp mixer designed for installed background music and PA systems.
Ideal for use in bars, restaurants, places of worship, conference rooms, schools, and wedding venues, it features multiple XLR and RCA inputs for flexible connectivity with microphones and external audio sources while saving space in compact installations.
A built-in media player supports Bluetooth streaming, USB playback, and an FM tuner, allowing easy access to various audio sources without additional equipment. The MM321 features 3 XLR microphone inputs with individually switchable +20V phantom power, 2 RCA aux inputs, and a dedicated RCA record output for capturing audio. The balanced XLR and 6.35mm mono jack outputs provide seamless integration with your existing background music or PA system.
Designed for professional installations, the MM321 includes 24V emergency mute contacts, making it compatible with fire alarm systems for safety-conscious venues. It can be powered by 100V, 240V, or 24V, offering flexibility for installations in a variety of locations. Rack-mount ears are included for secure integration into a rack cabinet or case.
With its versatile connectivity, built-in media playback, and emergency mute functionality, the Adastra MM321 is a reliable solution for audio management in commercial and public spaces.
Adastra MM321 Key Features:
- Multiple inputs – 3 XLR microphone inputs, 2 stereo RCA aux inputs, and 1 RCA record output
- Built-in media player – Bluetooth, USB, and FM tuner for flexible audio playback
- Phantom power – Individually switchable +20V phantom power for condenser microphones
- Balanced & unbalanced outputs – XLR and 6.35mm mono jack outputs for PA system integration
- 24V emergency mute contacts – Connects to fire alarm systems for enhanced safety compliance
- Rack-mountable – Includes rack ears for secure installation in a 19" cabinet or case
- Flexible power options – Operates on 100V, 240V, or 24V for versatile installations
- Ideal for professional venues – Bars, restaurants, conference rooms, schools, places of worship, and event spaces
Adastra - Commercial Amplifiers & Speakers

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
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.
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:
- Please keep your order reference to hand. This confirms your original order and gives us the necessary details to authorise the product's return.
- 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).
- 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.
- 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:
- 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.
- 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.
- 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.
- 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.
- Delivery charges will not be refunded unless the delivered goods are faulty.
- Replacement products are dispatched immediately after the returned goods have been received and accepted by Audio Volt.
- 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.

