Hey all, I have the ASrock Extreme6 Z87 using Purity Sound with my Senn HD 560 Ovation II's , Miles Davis Tributes and jesus it sounds amazing. I mostly use the HD 560 II's they're 20 years old now but damn do they sound amazing.
I came looking in here because I just now for first time ever plugged them into the rear panel jack and they sound better to me. Maybe I was over driving them on the front jack they are 300ohm but the highs sound much brighter to me on front jack. I think I just maybe had it up to loud or something. But I came looking because there was clearly a difference in what I was hearing, at times the highs were killing me on front jack, but now everything is in perfect balance using rear jack.
I don't have any noise that I can detect either on my board front or rear jack. And I'm pretty nit picky when it comes to that too so I don't think there is any on my board. I've had mine since July 2013.
I really been getting back into listening on headphones because I bought new cable and ear pads(original from Senn) and I always held the sound of them as the best sound I've ever heard. So I went back to listen to everything I own again. Here is video of them, see the ear pads though in pad shape still the replacement ear pads haven't come yet. So I'm sure sound will change some with brand new original pads come.