Unfortunately exceeds my expectations not in terms of loudness

I had bought this fan as a replacement for the existing of my receiver. 15 dB minimum seemed very quiet. Unfortunately I had to after installation notice that the fan is louder than the old one - and that too soon after switching on the receiver, ie at about 20 ° C.

Even the operation with 5 V voltage is not a solution, because it runs so - unlike many other 12 V fans - not only on what makes the bargain due to the restart function in an ongoing Klacker noticeable. Then pushes you it manually, it is nice quiet and also the airflow for my purposes sufficient, but of course not the solution.