Check the listing for details. PASS A3 Single-ended Class A Power Amplifier Kit / Amplifier Board 30W+30W. Condition: New. Listed at 39.99 USD. PASS A3 Single-ended Class A Power Amplifier Kit / Amplifier Board 30W+30W “amplifier kit" : This is a kit. include 2 channel PCB + All components. need yourself to solder them. "amplifier board" : This is one pair assembeld and tested board. (Tube amp Style) PASS A3 Single-Ended Class A Power Amplifier Kit. Free debugging. if Welding is correct. connect power Will can works. Reference to Famous PASS A3 circuit . All the FET are equipped same with the origianl machine, the input differentialTransistors using the new US FU9210, the power Transistors using the new origianl N-channel IRFP250, FET after precision matching, Sound style: Sweet and mellow, music taste very good, transparent.sound will be better than most of General amplifier. PCB Size: 122MMX74MM Operating voltage: Recommended DC: + - 25V ( The Transformer voltage recommned AC20V-0-AC20V. transformer power above 200VA) Power: 30watts @ 8ohms; 60watts @ 4 ohms Distortion rate @ 1 KHz: 1% at rated output; 0.003% @ 5 watts into 8 ohms Input impedance: 36kohm balanced, 18kohm single-ended Output noise: