Aune X7s Class A Balanced Audio Pre AMP HIFI Audiophile Headphone Amplifier Contents: Come with accessories in retail box. New Opened Box Condition. Features: The X7S is a fresh model in the popular Aune X series. This pure Class-A headphone amp meets the most demanding consumer. It is also a mini high-end desktop headphone amplifier that can drive most headphones and earphones.