I need some advice with two amps and two headphones, the fostex th-600. And the Hifiman HE5SE and the Aune t1s\x1s or Fiio K5 Pro. I can get both of this headphones for a good price, I lean toward the Fostex TH600(with ZMF ORI Pads) as I listen mainly to rock music, progressive rock, thrash metal, some classical and hip hop-electronics. The Hifiman HE5SE comes with Dekoni pads. The Fiio K5 Pro seems more powerful and with an added DAC. The T1s looks nice, But I don't want to get new and improved tubes for it if the original one is not good enough. The X1s looks good but older and maybe less powerful. thanks.