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 | evenly matched | Effectively the same output - 100W against 100W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Analogue inputs | evenly matched | The same number of line-level inputs (4). |
| Amplifier type | depends | Rogue Audio Sphinx v3 is Hybrid and Rogue Audio Cronus Magnum III is Tube. 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 | A | Rogue Audio Sphinx v3 costs less - $1,795 against $3,495 at list. |
| Watts per dollar | A | Rogue Audio Sphinx v3 is the cheaper watt - about $18 per watt against $35. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Rogue Audio Sphinx v3 B Rogue Audio Cronus Magnum III
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?
Rogue Audio Sphinx v3 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. Think about the whole system: the roughly $1,700 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.