Arcam PA720 Seven-Channel Power Amplifier

The Arcam PA720 is built for one purpose: to provide the main channel amplification in a reference-level home cinema system. Seven channels of Class G amplification at 100 watts per channel — all seven channels driven simultaneously — with a Class A bias of 20 watts per channel at the heart of the design. Pair it with the AV41 processor and you have the amplification side of a complete high-performance cinema system, with the PA410 or PA240 available to handle additional channels as the installation requires.

Where the PA720 Sits in the Arcam Range

The PA720 is the largest amplifier in Arcam's HDA power amplifier range. The PA410 handles four channels of Class AB amplification at 70W per channel — useful for height channels in an expanded Atmos system. The PA240 provides two channels of Class G amplification at 225W per channel, with 50W of Class A operation and a bridgeable option for demanding stereo or subwoofer applications. The PA720 covers the configuration that most serious cinema systems actually need: seven channels of consistent, high-quality amplification in a single unit.

Most people building around the PA720 start with it as the main seven-channel amplifier and add a PA410 for the four height channels of a full 7.1.4 Atmos system. This is the architecture the AV41's 16 balanced XLR outputs are designed for: the PA720 takes channels 1–7, the PA410 takes channels 8–11. The result is a fully separated, purpose-built amplification chain with no shared chassis between channels.

Class G Amplification

Class G amplification works by using two voltage supply rails rather than one. At low signal levels — quiet dialogue, ambient effects, low-level music passages — the amplifier runs from the lower rail, where the Class A bias operates: the first 20 watts per channel run in pure Class A, with the transistors conducting continuously and no switching artefacts in the signal. When the music or cinema soundtrack demands more, the higher voltage rail engages. The efficiency gains of Class G allow the power supply to be sized for real-world use rather than brief dynamic peaks.

At 100W per channel with all seven channels driven simultaneously, the PA720 does not compress or thermally throttle under sustained load. The rated specification is what you get in practice, not a peak figure achieved with only two channels driven.

Build Quality and Design

The PA720 is a physically substantial unit — the seven-channel topology and Class G power supply demand it. The acoustically damped chassis reduces vibration coupling into the signal path, which matters in a dedicated cinema room where the amplifier is under real acoustic pressure during playback. Balanced XLR and unbalanced RCA inputs are both fitted and switchable. Ethernet and RS232 control ports support integration with professional control systems and custom installation.

Technical Specifications

Who Is It For?

The PA720 is the right choice for anyone building a dedicated home cinema system around the AV41 processor and wanting all seven main channels amplified in a single, purpose-built chassis. It is also a compelling upgrade from a receiver-based system for anyone who wants to separate amplification duties from the processor. If you need four channels rather than seven, the PA410 covers that configuration at a lower price point. If your priority is the highest possible per-channel power for a stereo or two-channel cinema application, the PA240 is the right answer.

Buying from Martins Hi-Fi

Martins Hi-Fi has been in Norwich since 1968. Elizabeth Gould runs the business today, and we stock only brands we have heard properly and stand behind. Arcam have been a core part of our range for many years — Dave and Chris can talk you through whether the PA720, PA410 or PA240 is the right fit for your room and system, and have it set up in our Norwich showroom for you to hear.

Contact us at info@martinshifi.co.uk, call 01603 627010, or WhatsApp on 07554 687137. You can read more about how we work on our Why Martins Hi-Fi page. We are at 85–91 Ber Street, Norwich, NR1 3EY.