A valve amplifier against a solid-state one. They are not really rivals: they differ in character, in what they will drive and in what owning them involves, so start there rather than with the watts.
| Area | Better | Why |
|---|
| Power | A | T+A PA 2000 R has more power - 100W against 70W into 8 ohms. That is about 1.5dB, which is a small step in loudness but real headroom on peaks. |
| Analogue inputs | A | T+A PA 2000 R takes more analogue sources - 5 against 4. |
| Amplifier type | depends | T+A PA 2000 R is Solid State and Audio Research I/70 is Tube. Valve designs are usually warmer and softer at the limits and need their tubes replaced eventually; solid state is the lower-maintenance choice. This is a taste and ownership decision, not a quality one. |
| Shelf space | depends | Audio Research I/70 takes up about 23% less shelf area (1428cm² against 1863cm²), and it is 65mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Audio Research I/70 costs less - $9,950 against $11,490 at list. |
A T+A PA 2000 R B Audio Research I/70
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: T+A PA 2000 R measures better, Audio Research I/70 costs about 13% less. With most speakers in most rooms that gap is smaller in practice than it looks here.
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.