Great review Starfly. I'm glad you like them. I sure loved mine.

The drivers aren't the same, the 7520 improves upon the Z1000's.

Okay, the specs of the drivers are otherwise the same. They certainly don't sound the same

We have very similar ears.  I spent quite a bit of time with the 7520s at RMAF (Jude's pair) and it is every bit as good as you say.  I especially like your note about how some poor recordings may not fare as well through this can, agreed.  As for the notes on soundstage I think you hit it right on and I would add that for me the soundstage was a bit less in the head and more in front of the head, but very dependent on the recording.  I likened them a lot to my Shure 840s in this regard.  Where the 7520 trumps the Shure 840s, which are still good cans, is in detail, natural mids, treble detail without peakiness, and bass extension.  Wait a minute so they trump them all over the place.  I am a bit concerned about how well they will hold up physically over time, but they are one of the nicest sounding cans to come down the pike in a while.  My other favorite that I would put right up next to the Sonys but with a more intimate and slightly more forgiving sound is the Focal Spirit Pros, very nice as well.
 
Great review Starfly!

I've got the baby brother, the zx 700, and can only guess how your choice sounds.

@bixby, Thanks I think the angled drivers help to create that sense of the soundstage being in front of the head. But I know what you mean

Thanks, Very intriguing that you were able to compare to old the newcomers in the market, I'm in particular interstd in further comparative info with the Philips L2, Could you elaborate briefly on the similarities and key differences between them and the 7520's?

@Amarphael, I only had the L2 for 1 day, so I can't say too much about it. But if I recall correctly, the mids and highs were a bit more forward on the L2 and the bass was a bit more present. So overall a less neutral sound signature, a more warmish bass and somewhat more pushed mids and highs (not overdone though). The bass was still fairly tight though, but I don't think it's as tight as the 7520. It was actually quite an enjoyable headphone to listen to, just that the earcups were too small for my ears. In many ways they sound better than the P7, which is also a great headphone. And also I was really looking for a closed headphone, and the L2 is semi-open. But that openness certainly helped with creating a very expansive soundstage, if that's what you're looking for. Oh and in terms of design I think they're the coolest looking headphones of the whole bunch.
 
If you're looking for neutrality though, I think the 7520 is your best bet out of this lot. The pushed mids and highs could I suspect not sound too great on certain recordings, but if I'd had more time with the L2 I could've given you a more definitive answer. Sorry

I have the 7520 too and use them for mixing and mastering. I'm equally amazed at the details, the tonal balance and the resolution these headphones are capable of.
 
What surprised me the most is their ability to maintain all its qualities even down to very low listening levels. The clarity and resolution across the whole frequency range is contained all the way down to near silence, and I can actually mix at these low levels if I wanted to. I typically check my vocal and snare volume at these low levels - and none of the headphones I've used before in the studio comes even close to the 7520 in keeping clear and linear. The drivers must be very very sensitive or agile to be able to do this. And there is no congestion when you turn the level up. They stay clear and dynamic. Impressive.
 
I do have a small problem with comfort/fit. The lower edge of my ears rests on the driver grille. I don't notice this on the first 1-2 hours of use, but extending that to 2-3 hours of use, I feel a discomfort, a slight soreness. I am planning to place a soft tube or rope inside the cup to raise the pads a few millimeters and see if that helps.

any one tried to purchase the straight cable for these?