The issue here isn't that you're listening using headphones but that you're using YouTube. It's difficult to judge fidelity from such a lo-res source.
That sound is right for me.
It is youtube video and I am listening through headphone. It is really right sound for me. It is nothing to do with the speakers as I am listening through headphone. This guy has made preamplifier and power amplifier both by himself and they are both tube one.
My question is that which pre and power could have that high in the market? does not matter it is brand new or used.