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 | MOON 641 has more power - 125W against 100W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate T+A PA 2000 R the better fit for a small room, and MOON 641 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 | T+A PA 2000 R takes up about 17% less shelf area (1863cm² against 2239cm²), and it is 60mm 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 | MOON 641 is the cheaper watt - about $88 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 MOON 641
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?
MOON 641 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is.
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.