These are not the same size of amplifier: Yamaha R-S202 has roughly 3.3x the power of OSD Nero Stream XD. 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 | A | Yamaha R-S202 has more power - 100W against 30W 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. |
| Built-in DAC | B | OSD Nero Stream XD has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | A | Yamaha R-S202 takes more analogue sources - 4 against 1. |
| Room to grow | B | Only OSD Nero Stream XD offers preamp outputs and a subwoofer output - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Amplifier class | depends | Yamaha R-S202 is Class A/B and OSD Nero Stream XD is Class D. Class A/B runs warm and is the long-established mainstream choice; 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 | OSD Nero Stream XD takes up about 75% less shelf area (384cm² against 1506cm²), and it is 147mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | A | Yamaha R-S202 is the cheaper watt - about $3 per watt against $8. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Yamaha R-S202 B OSD Nero Stream XD
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?
Yamaha R-S202 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. 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 - Yamaha R-S202 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 70 watts would be headroom you pay for and never hear. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Yamaha R-S202 becomes the more rational buy.
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.