You have always highly recommended the NAD t762 receiver to me because I needed lots of power and quality to drive 4 ohm speakers...And for that I am greatful. BUT, Im hard headed and Im still kinda leanin towards the H/K AVR7200, and in a previous post you said that the H/K would drive 4 ohm speakers all around. A H/K rep emailed me and said that the H/K has plenty of power to drive the 4 ohms, but comfortably from fronts, however for a 5.1 or 6.1 set up it would get pretty hot and it would probably be ok to run them in a well ventilated area. If this is true would it help at prevent overheating to the amp from 4 ohm fronts, center and surrounds LSi series Polks along with the PSW 650 sub to put a small clamp on style fan aimed at the vents of the H/K to help cool it, Is this even nessasary?
I am not Hawk, but I will have a go at your questions. If I am wrong, please correct me Hawk.
I think that both the HK and NAD would both run very hot without adequate ventilation into a 4 ohm load - so given your concerns, preventative measures would be necessary.
A fan would be a good idea. However my preference is for a larger fan, as it can move more air at lesser RPM's with less noise. Do not direct the fan at the receiver vents, as you are only blowing the hot air back at the receiver. The idea is to move as much air away from the receiver as possible, so direct the fan at an cabinet opening would be more desirable. It might even be beneficial to create an opening on the other side of your cabinet to allow cool air to be drawn into the cabinet (convection cooling) and over the receiver.
Hope that helps.
No question that a 4 ohm load taxes an amp and the amp will generate a lot of heat. I am not as knowledgeable about the H/K 7200 as the H/K tech, so if it can handle a 4 ohm load, that is good news. My advice was based upon the info on their website and the fact that many people on this forum have written e-mails to other receiver makers and basically been told 6 ohms or higher.
Harry t gives good advice--make sure that the receiver has plenty of ventilation. An open stereo rack would probably be best. Don't put anything on top of the receiver and make sure that there is large amounts of air in front of, over and behind the receiver. I know the NAD 762 actually has two fans built into it. You may try getting a small fan, running at low rpms, to blow air over the top of the receiver, which will push the rising hot air away from the receiver.