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 | Parasound NewClassic 2125 v.2 has more power - 150W against 100W into 8 ohms. That is about 1.8dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate Schiit Vidar 2F the better fit for a small room, and Parasound NewClassic 2125 v.2 for a large room and a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | A | Schiit Vidar 2F holds up better into a 4-ohm load: its output nearly doubles to 200W, where the other increases strongly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Analogue inputs | evenly matched | The same number of line-level inputs (2). |
| Room to grow | evenly matched | The same expansion options on both. |
| Shelf space | depends | Schiit Vidar 2F takes up about 58% less shelf area (755cm² against 1781cm²), and it is 76mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Schiit Vidar 2F costs less - $799 against $1,250 at list. |
A Schiit Vidar 2F B Parasound NewClassic 2125 v.2
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. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Schiit Vidar 2F is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. Think about the whole system: the roughly $451 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
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.