Yes, I had an HK 525 for about a year, and now my Parents have it.

It does get quite warm. In my Parents cabinet, there is not much room on top, but it is open in the back. I also used to have it in a cabinet, but openned the back of the cabinet for more ventilation. The 525 also has a fan that comes on when it gets too warm.

When I got my new stand/rack, the 525 was out in the open, it still got pretty warm, but not as warm as when it was in the cabinet.

As hot as it got, it never had any problems.

-curtis