Siblings in Arcam's A range, so they share a design and a house sound. It comes down to power, features and price.
| Area | Better | Why |
|---|
| Power | B | Arcam A15+ has more power - 80W against 50W into 8 ohms. That is about 2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Arcam A5+ the better fit for desk or near-field listening and a small room, and Arcam A15+ for a mid-size room, a large room and a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output increases strongly (75W and 120W). |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (106dB vs 106dB). |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Analogue inputs | evenly matched | The same number of line-level inputs (3). |
| Use with a TV | depends | Only Arcam A15+ has HDMI eARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| Room to grow | evenly matched | The same expansion options on both. |
| Price | A | Arcam A5+ costs less - $1,200 against $1,500 at list. |
| Watts per dollar | B | Arcam A15+ is the cheaper watt - about $19 per watt against $24. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Arcam A5+ B Arcam A15+
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both amplifiers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
The usual trade-off: Arcam A15+ measures better, Arcam A5+ costs about 20% less. With most speakers in most rooms that gap is smaller in practice than it looks here. Start with the room. In a large or open-plan room, or with speakers that are hard to drive - low sensitivity, or an impedance that dips - Arcam A15+ has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 50 watts is already more than most people ever use, and the extra 30 watts would be headroom you pay for and never hear - we rate Arcam A15+ poorly for near-field use for exactly that reason. If this sits under a television, Arcam A15+ is the one to buy - HDMI ARC means the TV remote controls the volume and there is no second box in the way.
What a spec sheet cannot show: how either sounds with your speakers, how the controls feel day to day, and what the app is like to live with - which is where most all-in-one amplifiers are actually won or lost. Power figures are the manufacturers' own and are not measured to a common standard, so treat small differences as noise. If you can hear both, that will tell you more than any row above.