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 | AudioControl Rialto 600 has more power - 100W against 60W into 8 ohms. That is about 2.2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate AudioControl Rialto 600 the better fit for a mid-size room, a large room and a very large room, and Rotel A12 MKII for desk or near-field listening and a small room. Match the amplifier to the room you actually have, not the one you want. |
| Noise floor | B | Rotel A12 MKII is the quieter design on paper - 100dB against 96dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Both decode on board. Rotel A12 MKII goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Analogue inputs | B | Rotel A12 MKII takes more analogue sources - 4 against 1. |
| Phono stage | depends | Rotel A12 MKII has a built-in phono stage (MM) and AudioControl Rialto 600 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. |
| Room to grow | evenly matched | The same expansion options on both. |
| Amplifier class | depends | AudioControl Rialto 600 is Class D and Rotel A12 MKII is Class A/B. Class D runs cool and draws almost nothing at idle; Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | AudioControl Rialto 600 takes up about 75% less shelf area (410cm² against 1633cm²), and it is 190mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | AudioControl Rialto 600 costs less - $899 against $1,100 at list. |
| Watts per dollar | A | AudioControl Rialto 600 is the cheaper watt - about $9 per watt against $18. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A AudioControl Rialto 600 B Rotel A12 MKII
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?
The usual trade-off: Rotel A12 MKII measures better, AudioControl Rialto 600 costs about 18% less. With most speakers in most rooms that gap is smaller in practice than it looks here. Start with the room. In a large or open-plan room, or with speakers that are hard to drive - low sensitivity, or an impedance that dips - AudioControl Rialto 600 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 60 watts is already more than most people ever use, and the extra 40 watts would be headroom you pay for and never hear - we rate AudioControl Rialto 600 poorly for near-field use for exactly that reason. If you play records, Rotel A12 MKII 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.