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 | B | Buchardt I150 has more power - 150W against 100W into 8 ohms. That is about 1.8dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate Audiolab 9000A the better fit for desk or near-field listening, a small room and a mid-size room, and Buchardt I150 for a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | B | Buchardt I150 holds up better into a 4-ohm load: its output nearly doubles to 300W, where the other increases strongly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | B | Buchardt I150 is the quieter design on paper - 121dB against 110dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Both decode on board. Buchardt I150 goes higher - 394kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Analogue inputs | A | Audiolab 9000A takes more analogue sources - 3 against 1. |
| Phono stage | depends | Audiolab 9000A has a built-in phono stage (MM) and Buchardt I150 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 9000A offers a pre-out/main-in loop - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Headphones | depends | Only Audiolab 9000A has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | Audiolab 9000A is Class A/B and Buchardt I150 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 | Buchardt I150 takes up about 24% less shelf area (1147cm² against 1518cm²), and it is 32mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Buchardt I150 costs less - $2,500 against $2,999 at list. |
| Watts per dollar | B | Buchardt I150 is the cheaper watt - about $17 per watt against $30. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Audiolab 9000A B Buchardt I150
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?
Buchardt I150 is the easier recommendation: it leads on most of the measured areas and costs less. Take Audiolab 9000A if one of the "depends" rows above describes your system. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Buchardt I150 is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. If you play records, Audiolab 9000A 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.