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 | HiFi Rose RS520 has more power - 250W against 150W 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 NAD M32 the better fit for desk or near-field listening, a small room and a mid-size room, and HiFi Rose RS520 for a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output barely increases (150W and 250W). |
| Noise floor | A | NAD M32 is the quieter design on paper - 124dB against 109dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Both decode on board. HiFi Rose RS520 goes higher - 768kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Analogue inputs | A | NAD M32 takes more analogue sources - 4 against 1. |
| Phono stage | depends | NAD M32 has a built-in phono stage (MM and MC) and HiFi Rose RS520 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. |
| Use with a TV | depends | Only HiFi Rose RS520 has HDMI eARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| Headphones | depends | Only NAD M32 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | NAD M32 is Class D and HiFi Rose RS520 is Class AD. 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 | HiFi Rose RS520 takes up about 33% less shelf area (1135cm² against 1688cm²), and it is 60mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | NAD M32 costs less - $3,299 against $3,695 at list. |
| Watts per dollar | B | HiFi Rose RS520 is the cheaper watt - about $15 per watt against $22. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A NAD M32 B HiFi Rose RS520
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: HiFi Rose RS520 measures better, NAD M32 costs about 11% 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 - HiFi Rose RS520 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 150 watts is already more than most people ever use, and the extra 100 watts would be headroom you pay for and never hear - we rate HiFi Rose RS520 poorly for near-field use for exactly that reason. If you play records, NAD M32 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.