The fan is very noisy...At one time I tought the amp would take off and fly away ! It could be an exemplary error because I do not see many others complaining of this. But i checked, the fan was running free and it might be just a cheap type or so.... Anyway, because the rest of the amp is according to my wishes, I wanted to have a quick and sure solution...The local PC shop had a 12V noiseless fan ( Noctua) in stock that would fit in so I decided to replace the fan myself. . Now the amp is 100% according to my wishes, super quiet ! So I would recommend anyone who is bothered by a noisy fan : replace it by a Noctua !