Is there a way to have instant switch between on/off state of the wires?Currently I can only instantly switch wire on, switching wire off leads to redstone signal fading out.

My bad, it was TinkerMechworks SignalTerminal feeding back to the wire. Sorry, I should have tested it more before posting. Somehow I tunnel visioned on the wire and didn't realized it during testing.

I need a picture of your setup. This shouldn't happen.

Did a little bit more testing and I can't replicate it in clean environment. It most be other mod messing something up. Not sure what mod, but I will try to find out.