MUSE 6N11 Class A Hybrid Tube Headphone Amplifier High grade Caps , ALPS volume in use Precision select 6N11 valve, also match R/L channel within 1dB out put differential Using Elna, Wima Caps and Panasonic resistor THD: 0.016%(300 ohm) 0.45%(33 ohm) Please wait at least 20 seconds before connecting your headphone to this amplifier or turning on your power amplifier