2. amps-preamps
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RCA Shorting Plugs

I am coming to the conclusion that success in home audio reproduction is largely about lowering the noise floor. There are so many different types of “noise”, from so many different sources, that we only really “hear” by their absence.

I have had caps on the unused RCA inputs of my ASL passive autoformer preamp, ever since a friend suggested them way back. I recently got some actual shorting plugs (with resistors), from Hifi Collective in the UK, to replace them. I was surprised by how much difference they made. Transparency, resolution and musical flow all increased, along with the “realness” of instruments and voices. There is also more sense of the space around them.

I know some preamps short the unselected inputs, but, if yours doesn't, these shorting plugs are inexpensive, and definitely worth trying.
tommylion

Showing 4 responses by georgehifi

georgehifi's avatar
georgehifi
10,312 posts
 
shorting unused inputs **can only be advantageous, even if only theoretical** (electrical theory).

This is pure BS, because if they’re not used they are not connected to any active amplification circuitry!!
The only advantage they have is to keep dust out????

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
If it’s not used why switch to it?? And negative affect to what??

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
Buy switching to an unused input your subjecting the input first active stage to an open circuit.
The simple fix is not to switch to it, if it’s not used.
By putting blanking/shorting plugs on the unused inputs doesn’t make the used inputs sound any better.

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
If the selector switch is not switched to the input/s that you have the shorting plugs on, it is an open circuit, and a shorting plug should have no effect on an open circuit as it is not connected to in your case the Autoformer, and in an active preamps case, to the input stage transistors.

Cheers George   
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