I'm using the Noiseblocker NB-Multiframe M8-S3 in my iNuke NU3000 with excellent results. It's the loudest of the noiseblocker fans but very quit rated @ 19db and moves a decent amount of air. The amp is about 12 feet from my listening position and is inaudible.
you are absolutely right. I swapped the stock fan with this Noctua (80mm) in a NU1000, and it is dead silent, even without the LNA or ULNA (the fan doesn't start with this last one).
Now the Behringer has very good sound, without the fan noise flaw!
Fantastic, people, for your recommendation.