Cryogenic treatment of tubes? Anyone with experience positive or negative?

Not wanting to be the contrarian here but I have had very good results with Gold Lion 12 AU7s from Cryoset.  The pair in my linestage just stay quiet!  I have two more of the same in boxes in the stereo room closet waiting...

@georgehifi  My experience with the tubes mentioned above is just the opposite of what you posit.  I've had replacement tubes waiting in the wings for some time, expecting that my tubes would be getting noisy by now and would need to be replaced.  Not so.  They were quiet from the get-go and remain so.

Where I had trouble was with NOS tubes which got noisy so quickly that buying more of them after several tries just didn't make sense to me.  As always YMMV.

George,

Thanks for sharing the engineer's perspective!  Until proven otherwise through I'm sticking' with what's workin'.