TechPowerUp reviewed the Quick Look: aune BU2 Portable Bluetooth DAC/Amplifier
A quote from the article:
The aune BU2 is an update to the company's premium B-series of portable DAC/amplifier units and features a dual DAC ESS Sabre ES9318 chip with four amplifiers, an R-2R ladder network for precise volume control, high fidelity decoding and playback with both wired and wireless connectivity options, and 2.5 mm balanced and 3.5 mm SE headphone outputs.Quick Look: aune BU2 Portable Bluetooth DAC/Amplifier Review