I just bought a NAD T763 and I am wondering if the cooling fan never stops. It makes quite some noise!! It never stops even if there is no input going into the amp.
Due to the high current capabilty of your NAD T763, a few of the cooling fans will always run to maintain air movement.
Ensure that you have left at least 3-4 inches of clearance on the top of your unit and ensure that it is not on a soft surface that can impede air flow from the bottom where the 4 cooling fans are located.
As you incrase the volume the fans will increase speed to keep the unit cool.
If you are hearing alot of fan noise, your unit may have ingested some dust and is causing increased fan noise. Possibly a light vacuming of the bottom of the unit will correct this problem. Be sure to turn off the rear panel power before attmpting this.
In idle at low volumes you should barely be able to hear the fans.
If this does not rectify itself, contact your NAD dealer or NAD tech support (800-263-4641) for the name of a local service center to correct this problem.