The Fosi Audio GR40 is a versatile multi-functional tube preamplifier, DAC, and headphone amplifier that dramatically upgrades the sound of your system. Equipped with the advanced decoding chip ESS9028Q2M, it supports sampling rates of PCM up to 32Bit/384kHz and DSD256, ensuring lossless sound and significant noise reduction. At the same time, it features Bluetooth 5.1 (QCC3031) with support for aptX, aptX-HD, and aptX-LL for high-resolution wireless listening with minimal latency. With a variety of inputs (USB-C, Optical, Coaxial, Bluetooth) and outputs (Stereo RCA, 3.5mm Jack), it allows connection to active speakers or headphones 16Ω-300Ω, offering bass/treble adjustments and the warm, organic character provided by the built-in JAN5654W tubes in a compact aluminum chassis.