These are not the same size of amplifier: Yamaha A-S501 has roughly 2.4x the power of Cambridge Audio AXA35. That is about 3.9dB, so it is a question of room size and how hard your speakers are to drive, not of one being the better amplifier.
| Area | Better | Why |
|---|
| Power | B | Yamaha A-S501 has more power - 85W against 35W into 8 ohms. That is about 3.9dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Cambridge Audio AXA35 the better fit for desk or near-field listening and a small room, and Yamaha A-S501 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. |
| Speaker load rating | B | Yamaha A-S501 is rated down to 4 ohms against 8, so it is the safer partner for a low-impedance speaker. |
| Noise floor | B | Yamaha A-S501 is the quieter design on paper - 99dB against 82dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Yamaha A-S501 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Yamaha A-S501 takes more analogue sources - 6 against 5. |
| Room to grow | B | Only Yamaha A-S501 offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Price | A | Cambridge Audio AXA35 costs less - $399 against $550 at list. |
| Watts per dollar | B | Yamaha A-S501 is the cheaper watt - about $6 per watt against $11. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Cambridge Audio AXA35 B Yamaha A-S501
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: Yamaha A-S501 measures better, Cambridge Audio AXA35 costs about 27% 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 - Yamaha A-S501 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 35 watts is already more than most people ever use, and the extra 50 watts would be headroom you pay for and never hear - we rate Yamaha A-S501 poorly for near-field use for exactly that reason. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Cambridge Audio AXA35 becomes the more rational buy.
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.