So I think I found a solution to the high pitch whine of the stock fans. We all know the guide vanes are what's causing the pitch. I received a fan with a broken blade on my my batch 1 S5's and Bitmain was kind enough to ship me a new one. I decided to do a little experiment today to see if reducing the number of vanes would change the pitch, which for my ears (healthy 35 year old) now sounds more like a S3.
You notice on the vane there is a thicker part on the outer edge, I took some wire cutters and cut every other vane right where the thin part of the vane meets the thicker part (careful to line up the fan blades so you don't accidentally cut one). I then used my thumb and as close to center as possible I just pushed down on the cut vane and it popped right off. Note that the power wires run down one vane so you probably will want to start there and you'll still end up with an odd number of cuts. Here's a picture and for those brave enough to try it, let us know your results. My temps are exactly the same and I do use a high cfm pull fans as well. Still experimenting with those, so far the Silverstone Tek 140mm x 38mm Fan seems to be giving me the lowest temps but these S5's seem to run in all different temperature ranges so it's all subjective.
https://farm8.staticflickr.com/7515/16089177837_65df09d9d5.jpgThat has been my thought/plan if and when (a big if and when) I get S5s except I would be leaving only 3 or 4 vanes and Dremel the rest of them out "clean". If that will not be satisfactory, there's always the Delta fan option. I'm glad to know that it did make a difference.
