These are not the same size of amplifier: Parasound NewClassic 2125 v.2 has roughly 2.5x the power of Rotel A12 MKII. That is about 4dB, 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 | Parasound NewClassic 2125 v.2 has more power - 150W against 60W into 8 ohms. That is about 4dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Parasound NewClassic 2125 v.2 the better fit for a mid-size room, a large room and a very large room, and Rotel A12 MKII for desk or near-field listening and a small room. Match the amplifier to the room you actually have, not the one you want. |
| Built-in DAC | B | Rotel A12 MKII has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Rotel A12 MKII takes more analogue sources - 4 against 2. |
| Phono stage | depends | Rotel A12 MKII has a built-in phono stage (MM) and Parasound NewClassic 2125 v.2 does not. Decisive if you own a turntable, completely irrelevant if you do not - and an outboard phono stage is easy to add later either way. |
| Headphones | depends | Only Rotel A12 MKII has a headphone output. Worth something if you listen late, nothing if you never do. |
| Price | B | Rotel A12 MKII costs less - $1,100 against $1,250 at list. |
| Watts per dollar | A | Parasound NewClassic 2125 v.2 is the cheaper watt - about $8 per watt against $18. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Parasound NewClassic 2125 v.2 B Rotel A12 MKII
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?
Neither runs away with it - they trade advantages. Let the "depends" rows and the speakers you already own settle it. 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 - Parasound NewClassic 2125 v.2 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 60 watts is already more than most people ever use, and the extra 90 watts would be headroom you pay for and never hear - we rate Parasound NewClassic 2125 v.2 poorly for near-field use for exactly that reason. If you play records, Rotel A12 MKII saves you buying a phono stage; if you do not, ignore that row entirely.
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.