I just installed the SilenX IXP-34-08 in my Ultra and there was absolutely NO noise at all..
I followed GuitarDojo's method of (4) #6-32 x 1-1/4" lg. screws, and (8) #60 O-Rings. Using (2) O-Rings per screw (between the head of the screw & the fan, and another between the fan and the stand-off).
Now if I could only get rid of that very little bit of fan noise coming from my QSC GX3. LOL..
I followed GuitarDojo's method of (4) #6-32 x 1-1/4" lg. screws, and (8) #60 O-Rings. Using (2) O-Rings per screw (between the head of the screw & the fan, and another between the fan and the stand-off).
Now if I could only get rid of that very little bit of fan noise coming from my QSC GX3. LOL..