Opened box The hot new 2021 version of this very popular headphone amplifier!!! Now better than ever!! SILVER VERSION UK version, UK warranty, NO warranty for non UK versions. Its gain stage, which can be configured by switch, allows a perfect impedance matching for both low and high impedance headphones. Its structure is based on 8 Class A polarized transistors divided into 4 groups designed with a true symmetrical stage for cross talk and remote, inaudible background noise. The European sound of the Aune X7S developed by an English team has body, a deep sound image with increased natural musical tracking, a true sound signature of headphones amplifiers in class A. The separate 15 V regulated low noise power supply provides the stability necessary for the Aune X7S to operate properly in class A. By its unique design the Aune X7S will be an ideal companion for the aune X8 Magic DAC Product typeHeadphone amplifierClassAFrequency response20Hz-200kHz @ -0.3dBNoise level3µVTHD0.00013%Inter-modulation distortion (CCIF protocol)RCA : 0.000036%XLR 0.00057%Output powerRCA : 250mW @ 300 Ohm / 1000mW @ 32 OhmXLR : 1000mW @ 300 Ohm / 1700mW @ 32 OhmSNRJack 6.35mm : 117dBXLR : 125dBInput1x Stereo RCAOutputs1x Variable Stereo RCA1x Jack 6.35mm1x XLR 4 poles balancedSPECIFICATIONSDimensions145 x 171 x 45mmWeight2kgColorsilver