Different price classes - Rega Aethos costs roughly 1.6x what Rega Elicit MK5 does. Expect it to lead on paper; the question is whether you will hear the difference through the speakers you own.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 105W against 125W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Built-in DAC | A | Rega Elicit MK5 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Phono stage | depends | Rega Elicit MK5 has a built-in phono stage (MM) and Rega Aethos 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. |
| Price | A | Rega Elicit MK5 costs less - $3,345 against $5,395 at list. |
| Watts per dollar | A | Rega Elicit MK5 is the cheaper watt - about $32 per watt against $43. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Rega Elicit MK5 B Rega Aethos
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?
Rega Elicit MK5 is the easier recommendation: it leads on most of the measured areas and costs less. Take Rega Aethos if one of the "depends" rows above describes your system. If you play records, Rega Elicit MK5 saves you buying a phono stage; if you do not, ignore that row entirely. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Rega Aethos becomes the more rational buy.
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.