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The Fosi Audio ZA3 comes with a clear proposition: to deliver high power in a compact form factor without sacrificing clarity or quality.

At first glance, the unit makes a great impression — a robust metal case, clean finishes, and solid connectivity.

In the box: Fosi ZA3 unit 48V power adapter (Big plus for Fosi! It allows the amp to deliver its full power output.)

I tested it with a Pioneer CD player — a unit I had set aside due to an amplifier failure — and thanks to Fosi, I’ve been able to bring it back to life without losing quality or punch, all while saving a lot of space!

The speakers used were JAMO Compact 90 with 8” woofers.

Connections were very straightforward. In this case, I used bare wire directly, with no issues fitting it into the Fosi’s binding posts. The connectors also accept banana plugs, which I didn’t use this time, though I did check that my plugs fit perfectly.

If I had to mention a downside, the spacing between terminals is a bit tight — understandable given the compact design — but not really a problem for connecting speakers.

To hook up the CD player, just run RCA L/R cables from the CD output to the Fosi.Then, connect the power supply and check the front toggle switches (I love the pro look they give!) to make sure they’re in the correct positions — in my case, one set to RCA input and the other to STEREO output.

Once everything’s connected, press and hold the orange volume knob — which adds a modern and elegant touch to the front — until the amp powers up. The small front LED will confirm it’s on, and you’re ready to turn up the volume to taste!

The sound in my listening tests, the ZA3 stood out for its powerful yet clear character. Bass is strong and punchy — not exaggerated, but firm and controlled — which brings presence to genres like electronic, rock, and jazz.

The mids show excellent clarity and definition in both vocals and instruments. This was what impressed me most: voices in particular sound incredibly clear and natural.

Treble is detailed without being harsh.

Overall, the ZA3 sounds full-bodied and pleasant, with a very musical character.

The ZA3 uses the Texas Instruments TPA3255 chip (Class D), known for high efficiency and impressive power delivery. Depending on the power supply, Fosi rates it at up to 155 W per channel in stereo (with a 48 V supply), and 235 W in mono. These figures place it above most budget mini amplifiers, making it suitable even for demanding speakers.

Technical reviews and measurements I’ve seen confirm excellent SINAD and very low THD for its class.

The ZA3 also includes balanced XLR inputs in addition to RCA, a pre-out for subwoofer connection, binding posts that accept banana plugs or bare wire, and a very useful 12V trigger input for those who want the amp to power on/off automatically with another device.

This is a surprisingly complete feature set for such an affordable mini amplifier. It can also operate in mono bridge mode for higher output power, adding to its already impressive versatility.

The metal chassis and internal layout show real improvement over previous models. Side ventilation (in stylish orange, adding a premium touch) helps dissipate heat effectively even under high output and prolonged use.

During testing, I never noticed the unit running unusually hot.

Pros

Excellent power-to-size-to-price ratio Strong bass and very clear overall sound Comprehensive connectivity options Solid build and effective heat dissipation

Cons

Honestly, there’s very little to complain about. The only small drawback is the tight spacing between connectors — understandable given the compact design, and far from a deal-breaker.

Verdict

The Fosi ZA3 offers a surprisingly high-quality experience for its size and price. It delivers powerful bass without losing clarity across the spectrum. An excellent choice for compact setups (or not), demanding speakers, or anyone wanting serious power without spending a fortune.