Different price classes - Technics SU-GX70 costs roughly 2.1x what Denon PMA-900HNE 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 | B | Denon PMA-900HNE has more power - 50W against 30W into 8 ohms. That is about 2.2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Technics SU-GX70 the better fit for desk or near-field listening, and Denon PMA-900HNE for a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | A | Technics SU-GX70 holds up better into a 4-ohm load: its output nearly doubles to 60W, where the other increases strongly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | evenly matched | Only Technics SU-GX70 has Chromecast; only Denon PMA-900HNE has Roon and HEOS. Neither list is longer in a way that matters - check the one service you actually pay for. |
| Analogue inputs | B | Denon PMA-900HNE takes more analogue sources - 3 against 2. |
| Room to grow | B | Only Denon PMA-900HNE offers a subwoofer output - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Amplifier class | depends | Technics SU-GX70 is Class D and Denon PMA-900HNE is Class A/B. Class D runs cool and draws almost nothing at idle; Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Price | B | Denon PMA-900HNE costs less - $949 against $1,999 at list. |
| Watts per dollar | B | Denon PMA-900HNE is the cheaper watt - about $19 per watt against $67. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Technics SU-GX70 B Denon PMA-900HNE
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?
Denon PMA-900HNE is the easier recommendation: it leads on most of the measured areas and costs less. Take Technics SU-GX70 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 - Technics SU-GX70 is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. 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 - Denon PMA-900HNE has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 30 watts is already more than most people ever use, and the extra 20 watts would be headroom you pay for and never hear.
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.