No single best amplifier here. What decides it is what you have to drive, what you need to plug in, and how much of the system you want in one box.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 70W against 80W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output increases strongly (110W and 120W). |
| Noise floor | A | Audiolab 7000A 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. Cambridge Audio CXA81 goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Analogue inputs | B | Cambridge Audio CXA81 takes more analogue sources - 5 against 3. |
| Phono stage | depends | Audiolab 7000A has a built-in phono stage (MM) 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 | A | Only Audiolab 7000A offers a pre-out/main-in loop - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Price | A | Audiolab 7000A costs less - $999 against $1,499 at list. |
| Watts per dollar | A | Audiolab 7000A is the cheaper watt - about $14 per watt against $19. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Audiolab 7000A 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?
Audiolab 7000A 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, Audiolab 7000A saves you buying a phono stage; if you do not, ignore that row entirely. Think about the whole system: the roughly $500 saved by taking the cheaper one would buy better speakers or a subwoofer, and either does more for the sound than the difference between two competent amplifiers.
What a spec sheet cannot show: how either sounds with your speakers, how the interface feels 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.