They run extremely hot. From my experience, this is normal. I have a VK-51SE and originally placed it on the bottom shelf of my rack. After a few days, the left channel was not playing. After I checked that all the tubes were working, I placed it on the top shelf to give it more ventilation. I have never had a problem since. Even with all that ventilation, I would not be able to place my hand on the top of the unit for more than 10 seconds. Since the 52SE also uses the 6H30s, I would think it would run very hot as well.
Please let me know how you like the 52SE. I am considering upgrading. Have you also tried the Audio Research REf 3? I believe it is the same price and has received a great deal of praise on this site.
