These are not the same size of amplifier: Hegel H400 has roughly 3.3x the power of Hegel H150. That is about 5.2dB, 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 | Hegel H400 has more power - 250W against 75W into 8 ohms. That is about 5.2dB - a different class of amplifier rather than a bigger version of the same one, and far more than most rooms will ever ask for. |
| Room size | depends | We rate Hegel H150 the better fit for desk or near-field listening, a small room and a mid-size room, and Hegel H400 for a large room and a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Bass control | B | Hegel H400 has the higher damping factor (4000 vs 2000), which usually means a tighter grip on a woofer. Above about 100 the returns flatten out, so read this as a tendency rather than a ranking. |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (100dB vs 100dB). |
| Built-in DAC | B | Both decode on board. Hegel H400 goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Streaming | evenly matched | The same streaming platforms and services on both. |
| Analogue inputs | evenly matched | The same number of line-level inputs (3). |
| Phono stage | depends | Hegel H150 has a built-in phono stage (MM) and Hegel H400 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 | evenly matched | The same expansion options on both. |
| Shelf space | depends | Hegel H150 takes up about 20% less shelf area (1505cm² against 1892cm²), and it is 90mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Hegel H150 costs less - $3,600 against $7,700 at list. |
| Watts per dollar | B | Hegel H400 is the cheaper watt - about $31 per watt against $48. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Hegel H150 B Hegel H400
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: Hegel H400 measures better, Hegel H150 costs about 53% 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 - Hegel H400 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 75 watts is already more than most people ever use, and the extra 175 watts would be headroom you pay for and never hear - we rate Hegel H400 poorly for near-field use for exactly that reason. If you play records, Hegel H150 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.