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 | Rega Osiris has more power - 160W against 100W into 8 ohms. That is about 2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate T+A PA 2000 R the better fit for desk or near-field listening, a small room and a mid-size room, and Rega Osiris for a large room and a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Analogue inputs | evenly matched | The same number of line-level inputs (5). |
| Headphones | depends | Only T+A PA 2000 R has a headphone output. Worth something if you listen late, nothing if you never do. |
| Shelf space | depends | Rega Osiris takes up about 18% less shelf area (1519cm² against 1863cm²), and it is 55mm 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 | B | Rega Osiris is the cheaper watt - about $73 per watt against $115. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A T+A PA 2000 R B Rega Osiris
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?
Rega Osiris 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 - Rega Osiris has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 100 watts is already more than most people ever use, and the extra 60 watts would be headroom you pay for and never hear - we rate Rega Osiris poorly for near-field use for exactly that reason.
What a spec sheet cannot show: how either sounds with your speakers, how the interface feels 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.