These are not the same size of amplifier: Hegel H30A has roughly 5.5x the power of Hegel H20. That is about 7.4dB, 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 | A | Hegel H30A has more power - 1100W against 200W into 8 ohms. That is about 7.4dB - a different class of amplifier rather than a bigger version of the same one, and far more than most rooms will ever ask for. |
| Bass control | B | Hegel H20 has the higher damping factor (1000 vs 500), 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). |
| Analogue inputs | evenly matched | The same number of line-level inputs (2). |
| Shelf space | depends | Hegel H20 takes up about 36% less shelf area (1591cm² against 2473cm²), and it is 205mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Hegel H20 costs less - $7,200 against $20,000 at list. |
| Watts per dollar | A | Hegel H30A is the cheaper watt - about $18 per watt against $36. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Hegel H30A B Hegel H20
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?
Hegel H30A is ahead, but on only 1 of the measured areas, and it costs about 2.8x the price. That is a lot of money for a narrow margin - Hegel H20 is the sensible buy unless a specific feature above decides it for you. 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 H30A has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 200 watts is already more than most people ever use, and the extra 900 watts would be headroom you pay for and never hear - we rate Hegel H30A poorly for near-field use for exactly that reason. Think about the whole system: the roughly $12,800 saved by taking the cheaper one would buy better speakers or a subwoofer, which 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 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.