Obviously there are a couple of ways to do this. I found the most definitive to be using the same cord, one with a 15A IEC through the adapter and one with a 20A IEC. Now as I said earlier, it is a useful tool, as it did give me some insight into power cord differences, however, when I decided on the cord I wanted and ordered it with a 20A IEC, I was able to compare the same cord with 20A and 15A IEC's. Another way would be to use the 15A cord on other components with 15A IEC connections to get a good feel for the cord's sound, then use the adapter to run it through the 20A IEC. This is a bit more difficult, but is what led me to order the cord I liked with a 20A IEC. It gave me suspicions that the adapter was altering the sound.
In general, I found there to be a slight hardening of the sound, akin to a glassy-ness (is that a word?) in the upper midrange using the adapter, as well as a small, but noticeable, loss of resolution. This is what I was reffering to as the 'smear', a sort of softening of the note attack if you will.
All that being said, I am not bashing Voodoo products, and I still own two of these adapters (you'll never know when you'll want to try them). I also own a Voodoo 15A>Nema adapter so I can try other cords on my Hydra. FWIW, I don't find them anymore offensive than other adapters, like RCA>XLR adapters. My point was just that they are great tools for experimenting and trying different cords, and that's how I feel they should be used. Not as permenant staples in a system. Of course as with all things audio, YMMV.
Cheers,
John
