These are not the same size of amplifier: McIntosh MC830 has roughly 2x the power of McIntosh MC152. That is about 3dB, so it is a question of room size and how hard your speakers are to drive, not of one being the better amplifier.
| Area | Better | Why |
|---|
| Power | B | McIntosh MC830 has more power - 300W against 150W into 8 ohms. That is about 3dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Speaker load rating | A | McIntosh MC152 is rated down to 2 ohms against 4, so it is the safer partner for a low-impedance speaker. |
| Analogue inputs | evenly matched | The same number of line-level inputs (2). |
| Price | B | McIntosh MC830 costs less - $5,500 against $6,500 at list. |
| Watts per dollar | B | McIntosh MC830 is the cheaper watt - about $18 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 McIntosh MC152 B McIntosh MC830
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?
McIntosh MC830 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. 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 - McIntosh MC830 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 150 watts is already more than most people ever use, and the extra 150 watts would be headroom you pay for and never hear.
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.