Shorting plugs

I recently saw another thread on here discussing the same thing. Picked up a cheap pack of them off Amazon thinking "Well it was only $12. What could it hurt?" Yeah, after plugging them in and sitting down, I was in for a shock and awe experience. So much more clarity, less grain, less fuzz, more enjoyment. I'm sure some of this is gear dependent, but in my setup, that was absofreakinlutely money well spent.

nonoise - Thanks

@bob540

Wait — I thought shorts in electrical or audio cables or equipment is bad?!  But they were the solution? 

 

You don't want to short out a low impedance voltage or power source (an output) because it will draw high current. That's why people are saying to remove the center pin on shorting plugs for output jacks, as that turns the plug into a non-shorting cover that can't draw current.

But inputs are high impedance, and shorting them is safe and prevents stray noise from entering the system. 

Mama's little baby loves shortnin' shortnin'

Mama's little baby loves shortnin' plugs

I believe it really depends on the type of equipment you have and how the individual inputs get their signal to the amplifying stage.  In my particular preamp case, each input RCA goes back to a hard-wired input selector switch and is out of the actual circuit unless it's the one selected.  I suppose the wiring to all including the used input could be subject to stray RF (or other input analog signals) and that in some way is getting into the amplifying circuit, particularly if they might be bundled together back to the selector switch.  I worked on a friend's preamp who's inputs were bundled together back to the selector switch and interestingly, there were two inputs that were connected to two separate devices, (tuner and CD player).  When the CD player was selected but not playing, you could turn up the preamp volume control and hear the tuner playing and vice-versa.  Unbundling/separating the input wires and the sound from the other went away.  Also interestingly, it didn't matter which input was used with which devices as the cross talk was evident in all of the used ones.  So there was definitely cross talk between inputs happening.  I didn't even think of using shorting plugs on the unused input RCA's at the time, however I'm not sure they would have made a difference.  If you use them and notice a difference in improved sound, then it's all good and I believe each preamp will have its own input isolation or cross talk levels, including stray RF.  In my opinion, it's in the topology (and possibly the electronics) of how the input signals get to the amplifying stage.