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 | Arcam A15 has more power - 80W against 45W into 8 ohms. That is about 2.5dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Arcam A15 the better fit for a mid-size room, a large room and a very large room, and LEAK Stereo 130 for desk or near-field listening and a small room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output increases modestly (120W and 65W). |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (106dB vs 108dB). |
| Built-in DAC | B | Both decode on board. LEAK Stereo 130 goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Analogue inputs | A | Arcam A15 takes more analogue sources - 3 against 2. |
| Room to grow | evenly matched | The same expansion options on both. |
| Shelf space | depends | LEAK Stereo 130 takes up about 29% less shelf area (1115cm² against 1580cm²), and it is 25mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | A | Arcam A15 is the cheaper watt - about $12 per watt against $22. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Arcam A15 B LEAK Stereo 130
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?
Arcam A15 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 - Arcam A15 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 45 watts is already more than most people ever use, and the extra 35 watts would be headroom you pay for and never hear - we rate Arcam A15 poorly for near-field use for exactly that reason.
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.