So I bought a set of these guys a while back for my Krell KAV 400xi integrated amp, thinking mostly that there was a 50/50 chance it'd add something positive to the system. A few professional reviewers had come out for them, and a number of home users too, so again it seemed the cost was within my range of "try it and see" tweaks. I think the website hypes them a bit much BTW but for what it's worth here is where I got them.
Then when I got them I let them sit around for about six months because they also fit into the "too much trouble to un-hook my entire system for" type of project!
Anyway- I decided to do it the other night and hear if this whole exercise amounted to anything and I have to say, it did. To me, they definitely added some inner clarity to the overall sound of the amp, and a little more sparkle to the mids and highs. Depth seemed to be enhanced as well. Nothing Earth shattering, but worth $40 for. I'd give it a 5% boost to my overall enjoyment, which for a $2700 amp is about .01% of the cost- not a bad ratio. Will I now go through every piece of equipment I have searching for fuses to upgrade? No- these are just fine and make the most sense for replacing in the overall scheme of things. Cheers--