Nobsound Tube Amplifier NS-13D with 2 Vacuum Tube of EL34 , Hi-Fi, 100% Handmade Vacuum Tube Amplifier; Tubes: 5Z4P*1, 6N9P*1, EL34-B*2:Particularly Ideal for Vocal Music & Chords Class A Single Ended Amplifier to reduce distortion Stereo Hi-Fi Integrated Amplifier brings you exquisite & refined music Self-Biasing Design; Analog Inputs; Output tags for speaker impedance: both 4ohm & 8ohm. Nobsound NS-13D Amplifier is a good choice if you are a audiophile. You can enjoy all kinds of music with it , especially vocal music & chords.