Works voltage: AC115V or AC230V 

Suitable for 32-600ohm headset

Input impedance 50 kΩ

Frequency response 1Hz ~ 100kHz (-3dB)

THD (total harmonic distortion) 0,002% at 170 mW / 250 Ω

Channel separation> 82 dB

SNR 92 dB

Weight about 2kg

Size:220*52*191mm  (W*H*D)

This amp is base on Beyerdynamic A1. each channle using 2 pair Original BD139 140 in parallel, Strong thrust. With 30MV protection current,delay 7 seconds output audio. we have test this amp with Beyerdynamic DT series headphones, AKG K501, K601, K701, Sennheiser Headphones HD Series, all has very good performance.

1/4W 1% precision metal film resistors (made in TAIWAN)

BC high-end filter capacitances,South Korea SAMWHA Aureate electrolysis,

AUDIOPHILE MKP 4U7 400V 3% precision tinfoil capacitance

Origilal ST MC33078N opamp

Philips BD139、BD140 transistors(The same batch number)

Omron G2R - 2 12V Relay 700MV Protection circuit,7 seconds delay connect function.

Origianl ALPS 27 type potentiometer.

30W high quality quality Toroid Transformer.

High quality grinding RCA

Full Aluminum chassis

1 × HD-8-A1-PRO Headphone Amplifier