Starting this new thread because this subject/question keeps arising about
these two top headphones. Since it's creating plenty of discussion (and confusion),
this information can, I hope, help to sort out the situation..
The MDR-Z1000 and MDR-7520 are identical other than the color, supplied cable, and support offered by Sony.
("Support offered by Sony" = since the 7520's are part of Sony's "Professional Division",
Sony offers immediate telephone support and faster repair turnaround if there's an issue with them).
Both headphones are described by Sony as "Studio Monitors"
The 7520's marketing efforts are geared towards the professional market,
while the Z1000's are focused on the home audiophile market.
In the USA, both were announced and released at the same time.
Both are available in the USA and Europe, but evidently only the 7520'a
of the two are available in the UK.
The MDR Z1000 headphones are made in Thailand, where Sony has been making their headphones
for years. The stock cable, however, is made in China. And, while I've not yet seen manufacturing information
on the 7520's, I would have to assume it's the same once again.
Perhaps most importantly, the technical data i.e. specifications for the two headphones are identical.
[I should mention that I have the Z1000's and think they're terrific,
even more so since I replaced the stock cable. Credit to Sony for making that a cinch to do,
since the supplied cable has a standard 3.5mm mini plug at both ends. The end which
attaches to the (left) earcup does have a screw type locking collar, but any standard 3.5mm
mini plug seats firmly with a positive click.]