The FOSI Audio BT20A MAX is a Class D stereo amplifier  designed to power passive speakers with a high level of control and power in a compact format. It delivers up to 300W per channel under 2 and 4Ω (180W RMS), relying on a PFFB (Post Filter Feedback) architecture and a segmented power supply to maintain low distortion and a high signal-to-noise ratio, even under variable load conditions.

Designed for both compact Hi-Fi installations and scalable 2.1 systems, it combines comprehensive analogue connectivity with high-definition Bluetooth reception, supporting LDAC and aptX codecs in their advanced versions. This versatility allows it to function as the main amplifier in a modern home system, while maintaining stable, consistent performance suitable for a wide range of sources and speakers.

Fosi Audio BT20A MAX: Dual independent power supply

This signal control logic is extended by a power supply split between the analogue and digital stages, isolating switching currents from noise-sensitive circuits. The integration of ELNA capacitors ensures stable energy reserves while reducing high-frequency interference, resulting in more consistent voltage and fewer parasitic fluctuations. This functional separation helps preserve micro-dynamics and detail clarity, even at high levels.

Fosi Audio BT20A MAX: Bluetooth mode

The wireless section is based on a Qualcomm QCC3095 Bluetooth chip (Bluetooth 6.0), ensuring stable, low-latency transmission. Compatibility with LDAC, aptX Adaptive, aptX Lossless, aptX HD, aptX, AAC and SBC codecs allows the audio stream to be automatically adapted to the quality of the source and transmission conditions. This versatility ensures consistent playback for both critical listening and everyday digital use.