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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
gdhal's avatar
gdhal
1,641 posts
 
May I get a consensus please on the merits or lack thereof of shorting a USB B input? Reason I ask is my amp has a USB(B)  DAC which I'm not using. If I switch to that input and raise volume to 12 or beyond there is, not surprisingly, some amount of noise at the speaker.

I've alread shorted my unused RCA unused inputs. I cannot seem to find (google search) USB B shorting plugs, and in fact certain articles appear to caution against shorting USB inputs.

Opinions and/or links to such a part appreciated.

Thanks.
georgehifi's avatar
georgehifi
4,966 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
elizabeth
6,726 posts
 
If I made my own shorting plug with resistors..
(I own a big pile of unused but new RCA jacks)
What value resistor would I want to use?

Ditto XLR, (I assume I would solder the resistor(s) from the - and + to ground pin in an XLR plug)

gdhal's avatar
gdhal
1,641 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.

Hi George. To clarify, I'm not wanting or expecting the unused input to sound better. What I am expecting, however, is that by shorting an unused input, its potentially negative effect that it has (if not shorted) on a *used* input is minimized.
georgehifi's avatar
georgehifi
4,966 posts
 
If it’s not used why switch to it?? And negative affect to what??

Cheers George
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