... chip resistors, sound special ENLA electrolytic capacitors, tube, USB port, RCA terminals are gold-plated material, full ON regulator device. Amp ... , USB jack *1Output jackanalog RCA jack *1 , 6.5mm jack *1 Unpack : T1 24bit tube USB DAC ,power adapter(220/110V) ,PC ... USB cable , 6.5mm to 3.5mm stereo F adapter , User manual.Headphone amp insider impedance10ohmHeadphone Amp part AP measured ...