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 | evenly matched | Effectively the same output - 90W against 75W 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 (150W and 115W). |
| Noise floor | B | LEAK Stereo 230 is the quieter design on paper - 109dB against 106dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Both decode on board, but only LEAK Stereo 230 handles DSD. |
| Analogue inputs | A | JBL SA550 C takes more analogue sources - 3 against 2. |
| Use with a TV | depends | Only LEAK Stereo 230 has HDMI ARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| Room to grow | evenly matched | The same expansion options on both. |
| Amplifier class | depends | JBL SA550 C is Class G and LEAK Stereo 230 is Class A/B. Class G/H switches its supply rails to cut the heat a Class A/B design wastes; 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. |
| Price | B | LEAK Stereo 230 costs less - $1,695 against $1,999 at list. |
A JBL SA550 C B LEAK Stereo 230
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?
LEAK Stereo 230 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If this sits under a television, LEAK Stereo 230 is the one to buy - HDMI ARC means the TV remote controls the volume and there is no second box in the way.
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.