You can only "shunt" inputs, NO outputs !!! As to shunting the inputs on an amp, that might be tricky. They might be wired in parallel. Shunting one set would in effect short the signal going into the other input to ground. This could either result in a loss of sound or "bad things" depending on how the individual components were built.
As a matter of safety, i would strictly shunt inputs on a preamp. Since each input on a preamp is selected individually and none of them would share common signal paths, that SHOULD be safe ( so long as it was not an under-designed piece of junk ). As to shunting ANYTHING else, i would first contact the manufacturer and find out if it was "safe" in their opinion. Better to be safe than sorry.
As to Sws2's questions, it should lower your noise floor and help the sound to come from a blacker background. You might also be able to reduce crosstalk between sources, but this would depend on the device being used. Sean
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