Philips HP1000 user here.
I have to say, I was extremely happy with the cans when I bought them back in... 2004 I think. Or it could be 2005. Was upgrading from my Sennheiser HD497. More comfy, soundstage seemed wider, more instrumental details and nuances, more musical, more bass extension... Ah... that was the love of my life...
UNTIL I WAS POISONED BY THE HD600

Now I find that it is slightly harsh and bright, the bass extension is fake, or what some others would call the bass hump, and didn't have enough instrumental detail, didn't have enough musicality... of course, what am I comparing... they are headphones of totally different classes...
So yes. Today I still own my HP1000. And the use of the PAV2 has greatly improved the sound of the HP1000, improving the instrument separation, soundstaging, and revealing even more inner details. And giving the bass more extension, sometimes to the extent of faking it, but I can live with it. Hey, I spent only RM400, can't expect heaven in headphile rite?
Gosh what am I typing? Anyway that's the report of a HP1000 user here.