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 | B | JBL MA9100HP has more power - 140W against 110W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| Speaker load rating | B | JBL MA9100HP is rated down to 4 ohms against 8, so it is the safer partner for a low-impedance speaker. |
| Analogue inputs | A | NAD T 758 V3i takes more analogue sources - 4 against 2. |
| Phono stage | depends | JBL MA9100HP has a built-in phono stage and NAD T 758 V3i 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 | A | Only NAD T 758 V3i offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Built-in sources | depends | NAD T 758 V3i has a radio tuner built in. That is one less box if you still play discs or listen to radio, and dead weight if you do not. |
| Amplifier class | depends | NAD T 758 V3i is AB and JBL MA9100HP is D. Class A/B runs warm and is the long-established mainstream choice; Class D runs cool and draws almost nothing at idle. Modern examples of both measure well - judge by the rest of the page. |
| Price | B | JBL MA9100HP costs less - $1,760 against $2,299 at list. |
| Watts per dollar | B | JBL MA9100HP is the cheaper watt - about $13 per watt against $21. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A NAD T 758 V3i B JBL MA9100HP
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?
JBL MA9100HP has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If you play records, JBL MA9100HP 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.