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 | A | Schiit Vidar 2F has more power - 100W against 80W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| 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. |
| Noise floor | A | Schiit Vidar 2F is the quieter design on paper - 123dB against 106dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Arcam A15 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Arcam A15 takes more analogue sources - 3 against 2. |
| Phono stage | depends | Arcam A15 has a built-in phono stage (MM) and Schiit Vidar 2F 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 Arcam A15 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Shelf space | depends | Schiit Vidar 2F takes up about 52% less shelf area (755cm² against 1580cm²), and it is 34mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Schiit Vidar 2F costs less - $799 against $999 at list. |
| Watts per dollar | A | Schiit Vidar 2F is the cheaper watt - about $8 per watt against $12. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Schiit Vidar 2F B Arcam A15
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?
Schiit Vidar 2F is the easier recommendation: it leads on most of the measured areas and costs less. Take Arcam A15 if one of the "depends" rows above describes your system. 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. If you play records, Arcam A15 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.