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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
jaybe
386 posts
 
I just ordered a bunch of shorting plugs on eBay. What about for the unused spdif, XLR and USB ports, is there a need to treat these as well and are solutions available?
folkfreak's avatar
folkfreak
1,149 posts
 
Yes, you should cover unused digital inputs including AES/EBU and BNC -- cheaper shorting plugs are available from electronics suppliers but if you want bling the Telos products are great (but cost an arm and a leg)
elizabeth
6,726 posts
 
I use RCA and XLR caps. No shorting action. They also lower the noise floor.
I bought a lot of them off eBay from a seller in Taiwan. Well made and a fraction of the cost of AQ or Cardas caps.
Every single unused RCA or XLR in my system, audio and video have a cap on them.
tommylion OP
563 posts
 
I used RCA caps previously. While they did make a difference, there was definitely a noticeable improvement going from caps to actual shorting plugs, like these:

https://www.hificollective.co.uk/accessories/rca-shorting-plugs.html

Adding a GutWire Ultimate Ground Cable to one of the RCAs took things even further, but that's another thread 😉
geoffkait's avatar
geoffkait
14,147 posts
 
According to my calculations it’s unlikely that Cardas non shorting caps operate by preventing rf from entering the tiny diameter outlet/inlet. Maybe I’m not using the right dimension for the rf wave. I’m not claiming they don’t work, I believe they DO work. Ditto the unused wall outlets. Are they too small to worry about rf? RF wavelength at 800 Megahertz is about a foot. And at 10 GHz it’s more than an inch.
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