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. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output increases strongly (160W and 160W). |
| Noise floor | B | McIntosh MSA5500 is the quieter design on paper - 110dB against 97dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | McIntosh MSA5500 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Streaming | B | Only McIntosh MSA5500 has AirPlay 2, Chromecast and Roon. |
| Room to grow | B | Only McIntosh MSA5500 offers preamp outputs and a pre-out/main-in loop - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Amplifier type | depends | McIntosh MA252 is Hybrid and McIntosh MSA5500 is Solid State. 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. |
| Shelf space | depends | McIntosh MA252 takes up about 46% less shelf area (1347cm² against 2512cm²), and it is 126mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | McIntosh MA252 costs less - $5,000 against $8,000 at list. |
| Watts per dollar | A | McIntosh MA252 is the cheaper watt - about $50 per watt against $80. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A McIntosh MA252 B McIntosh MSA5500
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: McIntosh MSA5500 measures better, McIntosh MA252 costs about 38% less. With most speakers in most rooms that gap is smaller in practice than it looks here. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and McIntosh MA252 becomes the more rational buy. Think about the whole system: the roughly $3,000 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.