At the heart of the BT20A MAX power amplifier stage is the Texas Instruments TPA3255 chip. Class D operation enables high output power in a compact enclosure, while allowing the amplifier to drive a wide range of passive speakers.

The amplifier uses PFFB, or Post-Filter Feedback. This system includes the signal after the output filter in the feedback loop, helping to reduce distortion and improve output control.

The BT20A MAX is designed to drive speakers with an impedance between 2 and 8 Ohms. Available output power is influenced by the connected speaker impedance, supply voltage, and the current capacity of the power supply in use.

Maximum output power is 2 x 300 W into 4 Ohms, while rated RMS output power is 2 x 180 W into 4 Ohms. The BT20A MAX operates from a DC 32-48 V supply and is available with different factory power supply options, so the actual available power reserve also depends on the power supply being used.

Inside the unit, the digital and analog circuit sections are powered from separate supply rails. This separation is designed to reduce interference between different functional sections, providing a more stable electrical environment for the audio circuitry.

The dual-rail power architecture is complemented by Japanese ELNA capacitors. Separate power delivery for the digital and analog stages also supports the operation of the PFFB system while contributing to the conditions required for low-noise and stable amplifier performance.

Wireless connectivity is provided by a Bluetooth 6.0 system based on the Qualcomm QCC3095 platform. In addition to standard SBC and AAC, the BT20A MAX supports multiple high-resolution and adaptive Bluetooth audio codecs.

Supported codecs include aptX, aptX HD, aptX Adaptive, aptX Lossless, and LDAC, with a maximum audio resolution of PCM 24 bit / 96 kHz.

In addition to Bluetooth, two separate analog stereo RCA inputs are available, allowing multiple wired sources to be connected.

The stereo speaker outputs and dedicated subwoofer output allow the unit to operate in both 2.0 and 2.1 configurations, eliminating the need for an external signal splitter when integrating an active subwoofer into the system.

The rear-panel HPF switch determines whether the main speakers receive the full frequency range or whether the lowest frequencies are filtered out. This is particularly useful for optimizing 2.1 systems built around an active subwoofer.

The BT20A MAX offers two HPF modes. In Full Range mode, the speaker output covers 20 Hz-20 kHz, while enabling the high-pass filter sends an 80 Hz-20 kHz signal to the main speakers. This removes the load below 80 Hz from the main speakers.

Volume is controlled by a motorized analog potentiometer, allowing the traditional physical control to be adjusted remotely. The included infrared remote control also provides access to several essential operating functions.

The remote control can be used to adjust volume and select inputs, while music playback can also be controlled in Bluetooth mode.

Heat dissipation from the high-power TPA3255 amplifier stage is supported by a cooling system with a built-in fan. The active airflow is designed to maintain a stable operating temperature even under higher loads.

The upgraded cooling design provides 30% greater cooling efficiency compared with the BT20A Pro. This plays an important role in balancing the compact enclosure with the amplifier's high output power.