Cardas Machined RCA Caps.???


I have seen many ads about the benefits of using these caps to avoid noise on the non-used RCA inputs...Somebody even posted an anouncement today at Audiogon.
Has someone ever tried these caps? Is it really beneficial and acoustically audible?
What do you think?
gecus
I use them, but I haven't really identified an audible difference. I live in an area where there isn't a lot of steady electromagnetic noise. Perhaps there is an audible improvement when a noise source comes close (e.g., electrically noisy diesel motor).

I understand the principle of better shielding, and I believe it is desireable. I believe my system can sound audibly better based on the cumulative benefit of a number of individually inaudible improvements, and this could be one such.
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I have then also. Can't swear they help, but not taking them off eihter. I also have good power and low noise to begin with.I consider tehm dust protection too.