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.
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?