I am just seeking some professional advice on the Marantz PM6004. I am just curious to find out about the quality of the amps headphone output. I feel the amp will be perfectly suited to my Wharfedale Diamond 10.1's but I also need something to drive my AT-ESW9's for isolated listening instead of having to spend an extra $200 on a dedicated headphone amp. Also, with monetary concerns in mind, how would anyone feel the difference between the 5004 and the 6004 will be for driving my 10.1's? Considering a phone input is a priority?