Arcam PA720 Seven-Channel Power AmplifierSeven channels of amplification in a single chassis is a practical requirement for anyone running a full surround system — front left, centre, front right, two surrounds, and two height channels all need driving, and they all need driving properly. The PA720 is Arcam's answer to that requirement: a dedicated seven-channel power amplifier built around Class G amplification, with enough power per channel to handle whatever an AV processor sends it.At 100W per channel with all seven channels driven simultaneously, the PA720 does not compromise on power to achieve its channel count. That figure — all channels driven, not a cherry-picked two-channel measurement — is the honest one, and it is a meaningful statement about the PA720's power supply engineering.Class G AmplificationClass G is Arcam's preferred amplifier topology across their HDA range, and the PA720 demonstrates why. A conventional Class A/B amplifier operates from fixed supply rails — the full voltage is always present, whether the signal demands it or not. Class G uses multiple supply rails at different voltages, switching between them according to the signal level. Low-level signals draw from the lower rail, where efficiency is high and distortion is low. Only when the signal demands it does the amplifier draw from the higher rail.The practical result is an amplifier that runs cooler, wastes less energy, and operates in a lower-distortion region for the vast majority of programme material, since most music and film soundtracks spend most of their dynamic range well below peak levels. The first 20W of the PA720's output operate in Class A, covering the signal levels where the ear is most discriminating.Power SupplyThe PA720's power supply is built around a toroidal transformer — a design choice that minimises electromagnetic interference radiated into the chassis compared with conventional laminated transformers. The chassis is acoustically damped, and the output stages use paralleled transistors to distribute thermal load and increase current delivery.InputsThe PA720 accepts both RCA and balanced XLR inputs, switchable. For a dedicated AV installation fed from a processor with balanced outputs — such as the Arcam AVR31 — the balanced connection is the correct choice, rejecting common-mode noise across the cable run between processor and amplifier. For systems using unbalanced interconnects, the RCA input is provided without compromise.Control and IntegrationEthernet and RS232 control ports are provided for custom installation and automation systems. The PA720 is designed to integrate into a wider AV system — whether a dedicated home cinema room with a full control system, or a simpler setup where the processor handles source switching and the PA720 handles amplification cleanly.Technical Specifications Specification Value Channels 7 Power output 7 × 100W, Class G (8Ω, 20Hz–20kHz, 0.2% THD) Amplifier class Class G, with 20W Class A operation Power supply Toroidal transformer Inputs Switchable RCA or balanced XLR Control Ethernet, RS232 Who Is It For?The PA720 is for the serious home cinema installation where a single receiver's built-in amplifier stages are no longer sufficient — either because the loudspeakers demand more current than a receiver can provide, or because separating the amplification from the processing is the correct engineering decision. Paired with the Arcam AVR31 or the Arcam AVR11, it forms the core of a system where every channel is driven with the same commitment to quality.It is not the right choice for those who want a simple all-in-one solution — the AVR11 covers that requirement. The PA720 is for those who have outgrown it.Buying from Martins Hi-FiMartins 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.The PA720 is available to discuss at our Norwich showroom, where we can demonstrate it in the context of a complete Arcam AV system and advise on the correct processor and loudspeaker pairing for your room.When you get in touch, you'll be speaking with Dave, Chris and Tim — experienced specialists who can advise on this product and your whole system.Contact us at [email protected], 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.
