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 | evenly matched | Effectively the same output - 250W against 250W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Grip on hard loads | A | Parasound JCM250 holds up better into a 4-ohm load: its output nearly doubles to 450W, where the other barely increases. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | A | Parasound JCM250 is the quieter design on paper - 120dB against 109dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | HiFi Rose RS520 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | A | Parasound JCM250 takes more analogue sources - 2 against 1. |
| 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. |
| Amplifier class | depends | Parasound JCM250 is Class A/AB and HiFi Rose RS520 is Class AD. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | HiFi Rose RS520 takes up about 49% less shelf area (1135cm² against 2226cm²), and it is 180mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | HiFi Rose RS520 costs less - $3,695 against $4,250 at list. |
A Parasound JCM250 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: Parasound JCM250 measures better, HiFi Rose RS520 costs about 13% less. With most speakers in most rooms that gap is smaller in practice than it looks here. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Parasound JCM250 is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. If this sits under a television, HiFi Rose RS520 is the one to buy - HDMI ARC means the TV remote controls the volume and there is no second box in the way.
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.