Beyerdynamic A1 Headphone Amplifier (Discontinued by Manufacturer) Intelligent circuit design with microcontroller capable of 96 kHz Input impedance 50 k Maximum Amplification 18 dB Two stereo audio inputs for two sound sources (RCA) Audio connections -- Headphone socket, 1 Line output Output power 100 mW / 600, 170 mW / 250 . 150 mW / 30 v -- T.H.D. 0.001% at 170 mW / 250 -- Mica capacitors only; no ceramic capacitors due to their generation of voltage under stress Very reliable cooling concept; including permanent short circuit protection on the output