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
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
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Non shorting plugs prevent rf from getting inside the component. Dust actually won’t go into unused outlets/inlets unless there’s a good crosswind. 😀  Yeah, I know what yer thinking: The holes are too small for rf to get into them. Just like rf gets into unused wall outlets, including non audio outlets. Same idea. RF is like Chickenman. He’s everywhere, he’s everywhere!! 🐥
Furthermore, it’s quite possible that shorting caps - at least in some cases - simply do what non-shorting caps do — prevent RF from entering the component and wreaking havoc on the audio signal and everything else.
This is pure BS, because if they’re not used they are not connected to any active amplification circuitry!!
True that an unused input is not connected to active amplification circuitry. However, it is somewhat irrelevant within the context and spirit of this thread, and as a reply to my statement that you were quoting: "shorting unused inputs **can only be advantageous, even if only theoretical** (electrical theory)."

The unused inputs could be close enough to active amplification circuitry, causing the unused input to contribute to the overall "noise floor" of the system. Granted, in a perfect world the amplifiers active input would be adequately shielded to prevent what I’ve described, but as you know, we certainly are not living in a perfect world.

This is why I indicated "shorting unused inputs CAN only be advantageous, even if only theoretical". I did NOT indicate it *necessarily is or always would be* advantageous.

Non shorting plugs prevent rf from getting inside the component.
I think what you mean to indicate here is that non shorting plugs *could* mitigate the effect of rf from getting inside the component; not prevent it. RF has a habit permeating audio related gear regardless of whatever is done to prevent it.