I have a Marantz SR5011 that specs good DACS, compressed file compensation, etc. I recently got 6xx's and a Pioneer XDP-30R Portable HR Digital Audio Player. Could anyone please tell me if my Marantz SR5011 will drive the 6xx's or I really need to buy a dedicated headphone amp (say a JDS Atom or Liquid Carbon, etc.)????? Thank you !!!