One is a streaming all-in-one and the other is an amplifier. Judge them on how many boxes you want and what you already own, not on the spec sheet alone.
| Area | Better | Why |
|---|
| Power | B | Sonos Amp has more power - 125W against 100W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | evenly matched | Only Sonos Amp has AirPlay 2. Neither list is longer in a way that matters - check the one service you actually pay for. |
| Phono stage | depends | Cambridge Audio AXR100 has a built-in phono stage and Sonos Amp does not. Decisive if you own a turntable, completely irrelevant if you do not - and an outboard phono stage is easy to add later either way. |
| Use with a TV | depends | Only Sonos Amp has HDMI ARC, 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 | B | Only Sonos Amp offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Amplifier class | depends | Cambridge Audio AXR100 is Class A/B and Sonos Amp is Class D. Class A/B runs warm and is the long-established mainstream choice; Class D runs cool and draws almost nothing at idle. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Sonos Amp takes up about 67% less shelf area (518cm² against 1591cm²), and it is 132mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | B | Sonos Amp is the cheaper watt - about $6 per watt against $7. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Cambridge Audio AXR100 B Sonos Amp
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?
Sonos Amp has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If you play records, Cambridge Audio AXR100 saves you buying a phono stage; if you do not, ignore that row entirely. If this sits under a television, Sonos Amp 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.