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?
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.
The cardas units just cover the RCA instead of shorting the center conductor the correct way.

The shorting types work great on unused coax output and all unused pre-amp inputs.
This tweak cannot be heard on lower resolution or high noise floor systems.

Make your own and have at it!

I just purchased a bunch of these here on A'gon, and can say that they make a slight difference in the noise floor. They don't fix major problems and don't effect soundstage etc. but they weren't designed to do that. IMO, it all depends on how well your system is setup. If your cables are all squared away (power cables not touching or crossing interconnects) I think the improvement will be noticable. As a side note, they did make an improvement on my TV, the picture is a bit more crisp, I had some left over and went to my video side to use them. I didn't think it would do anything, but it turns out, they are great for that too! Improvements in 2 areas for a small amount of cash.

Some preamps don't like their inputs shorted, that is why Cardas makes their RCA Caps with no shorting center conductor.