Different price classes - Denon PMA-3000NE costs roughly 2.5x what Cambridge Audio CXA81 does. Expect it to lead on paper; the question is whether you will hear the difference through the speakers you own.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 80W against 80W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Grip on hard loads | A | Denon PMA-3000NE holds up better into a 4-ohm load: its output nearly doubles to 160W, where the other increases strongly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | A | Denon PMA-3000NE is the quieter design on paper - 110dB against 105dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Both decode on board, but only Cambridge Audio CXA81 handles DSD. |
| Phono stage | depends | Denon PMA-3000NE has a built-in phono stage and Cambridge Audio CXA81 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. |
| Room to grow | B | Only Cambridge Audio CXA81 offers a subwoofer output - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Shelf space | depends | Cambridge Audio CXA81 takes up about 23% less shelf area (1595cm² against 2066cm²), and it is 105mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Cambridge Audio CXA81 costs less - $1,499 against $3,799 at list. |
| Watts per dollar | B | Cambridge Audio CXA81 is the cheaper watt - about $19 per watt against $47. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Denon PMA-3000NE B Cambridge Audio CXA81
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?
Cambridge Audio CXA81 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Denon PMA-3000NE is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. If you play records, Denon PMA-3000NE saves you buying a phono stage; if you do not, ignore that row entirely.
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.