How the BT20A MAX Delivers Big Sound from a Compact Design

The BT20A MAX is the newest addition to Fosi Audio’s amplifier lineup. It builds on the success of the BT20A and BT20A Pro, combining stronger wireless performance, higher stability, and more features into a sleek, modern design. Whether you’re upgrading a desktop setup, adding power to your living room speakers, or building a 2.1 system with a subwoofer, the BT20A MAX aims to deliver the best sound quality yet in this size class.

The secret behind the BT20A MAX’s sound quality lies in its engineering.

Inside, you’ll find:

• Independent digital and analog power supplies

• Premium ELNA capacitors

• PFFB technology

This architecture pushes distortion extremely low and raises the signal-to-noise ratio. It also reduces output impedance and stabilizes frequency response across different speaker loads, delivering a clean, natural, and detailed sound.

It’s a compact amp that behaves like a much larger, more expensive unit.

Bluetooth Performance That Stands Out

Wireless audio is a major strength of the BT20A MAX.

Using Qualcomm’s QCC3095 Bluetooth 6.0 chipset, the amp supports a full suite of modern codecs:

• SBC / AAC

• aptX, aptX HD, aptX Adaptive, aptX Lossless

• LDAC

This means stable, low-latency, high-resolution streaming from phones, tablets, or computers — perfect for both casual listening and critical music enjoyment.

Simple Setup, Versatile Inputs & Outputs

The BT20A MAX adapts to your system, whether simple or more advanced.

Connection options include:

• Dual RCA inputs

• Subwoofer output

• Passive speaker outputs

• 2.1 stereo system support

Bass and treble controls allow you to tune the sound to your preference, while EQ bypass gives you a pure signal when you want complete transparency.

Even better, the motorized analog volume knob means you can control volume precisely from the remote, just like a traditional HiFi amplifier.

To maintain performance, the BT20A MAX features an active cooling design:

• A built-in silent fan

• Ventilation on the top and sides

This improves cooling efficiency by about 30%, allowing the amplifier to run cooler during extended listening sessions or when driving demanding speakers.

Serious Power in a Compact Size

Don’t let the small footprint fool you — this amp packs real output:

• 300W × 2 (max) @ 4Ω

• 180W × 2 (RMS) @ 4Ω

The class-leading TI TPA3255 chip is responsible for that power and dynamic range.

And despite that performance, the BT20A MAX measures only:

• 14.9 × 14 × 4.5 cm (approx. 5.87 × 5.51 × 1.77 in)

It fits perfectly on a desk, bookshelf, or living room cabinet, without clutter.

Perfect for 2.1 Systems

If you love bass, you’ll appreciate the integrated subwoofer output.

Just connect your passive speakers and a subwoofer, and you have a rich, full-range system, ideal for music, movies, gaming and TV audio.

The High-Pass Filter can remove low frequencies from the main speakers, improving clarity and keeping everything tight and controlled.

How Does It Compare?

If you already know the BT20A or BT20A Pro, here’s how the MAX compares:

In short:

• BT20A MAX brings the biggest leap in wireless performance and features

• It’s the only one with subwoofer output and 2.1 capability

• It’s the quietest, cleanest, most powerful version

The BT20A MAX is not just another update — it’s a leap forward for compact amplifiers. Whether you’re upgrading a desktop system, building a living room HiFi, or replacing a bulky receiver, this amp offers big performance without big size.

If you’ve been waiting for the right moment to try one, this might be it.