Do "Cardas Caps" make a difference?


A new inexpensive, and quite compelling, tweek are the caps George Cardas makes to cover unused input and output jacks, therefore rejecting stray EMF. This is a logical tweek, and I trust George's integrity here, but my question is: How noticeable is the improvement? Can everyone who has tried them hear a difference?
fzxguy
You will gain more ( on most systems ) by using / building "shunts" than by using "shields". The parts can be procured from Rat Shack and will set you back WAY less than what a set of the aforementioned "caps" cost.

The difference between shunts and shields are that shunts can only be used on unuesed inputs whereas shields can be used on any unused rca jack. As such, you can shunt the unused inputs and shield the unused outputs for maximum effectiveness. Sean
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The Cardas caps were among a group of tweaks reviewed not long ago in "The Sensible Sound" (TSS). Now, I realize that TSS is not the ultimate high-end reviewer, but several of their writers have good systems, and like the rest of us, they have two ears and the ability to judge effects of tweaks on their system. The TSS article pretty much concluded that the Cardas caps added nothing (at best) and maybe even degraded the sound a bit.

Personally, I think that if you are concerned about dust getting into the inside of a component, then a plastic cap will work fine, and it's a whole lot cheaper than the Cardas gizmos. If your concern is about shunts vs. shields, then Sean has already given the best response above, and there is no need for me to comment further. (Good job, as always, Sean.)
I have been using them for a little over a year and really didn't notice any sonic differences. It was just that "peace of mind" thing, they keep out dust and they look nice. There's even a signature version, or something like that.
I have 90 of them installed. Couldn't hear any difference but I could swear my VCR's picture was less grainy after installing on the unused inputs. Testing with them on and off did produce a difference that only I could see. In other words, they probably do close to nothing. However, they look good (especially on front inputs) and they protect the RCA connector itself. Knowing what I know now I probably would have gotten plastic covers for protection only but I'm not dissappointed with the Cardas caps. Sean's idea is probably the way to go but I've heard many preamps don't like shorted inputs (I have no personal experience with that).
You might notice that the Cardas ads claim that the caps help prevent RF noise from entering the system. They do NOT say that they eliminate RF noise. Nor do they claim to have any effect on the biggest sources of RF noise such as ground loops and cabling.