The Topping EXT90 is a compact and versatile audio device designed primarily for use in high-fidelity audio systems. It serves as an advanced external DAC (Digital-to-Analog Converter) and headphone amplifier, catering to audiophiles seeking improved sound quality from their digital audio sources. The EXT90 is equipped with multiple input options, including USB, optical, and coaxial, making it compatible with a wide range of devices such as computers, TVs, or media players. It features high-resolution support, capable of decoding audio formats up to 32-bit/768kHz for PCM and DSD256 for DSD streams. The device employs high-performance DAC chips which provide low distortion and high signal-to-noise ratio, ensuring accurate audio reproduction. Additionally, the headphone amplifier section is designed to drive various headphone impedances, making it suitable for both high and low impedance headphones. The EXT90 is often praised for its sleek, minimalist design and solid build quality, making it an aesthetically pleasing addition to any audio setup. Users appreciate the overall clarity and detail it brings to their listening experience, as well as the versatility it offers in terms of connectivity and compatibility with multiple audio formats.