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 | B | Rogue Audio Sphinx v3 has more power - 100W against 72W into 8 ohms. That is about 1.4dB, which is a small step in loudness but real headroom on peaks. |
| Built-in DAC | A | Rega Elex Mk4 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | A | Rega Elex Mk4 takes more analogue sources - 5 against 4. |
| Amplifier type | depends | Rega Elex Mk4 is Solid State and Rogue Audio Sphinx v3 is Hybrid. 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. |
| Price | B | Rogue Audio Sphinx v3 costs less - $1,795 against $1,895 at list. |
| Watts per dollar | B | Rogue Audio Sphinx v3 is the cheaper watt - about $18 per watt against $26. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Rega Elex Mk4 B Rogue Audio Sphinx v3
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 you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Rogue Audio Sphinx v3 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.