A redstone torch makes a "pshh" sound whenever it is activated (i.e. extinguished) by a powered solid block or Block of Redstone that it is attached to. If this is the new burn out sound described in the 1.1 changelog, I would expect it to make this sound only when it actually burns out, that is, when it is wired into a short duration feedback loop that causes it to change state too many times in one second.

May relate to MCPE-11344