Are you referring to the Sylvania or Raytheon 6EW7 clear top, fat bottle tubes compared to your RCAs and GEs???
If so, they do seem to have greater resolution in the mids and highs, with slightly less bass emphasis. Very airy and open with lots of detail.
I have one pair of Raytheon and one pair of Westinghouse. No idea who made for Westinghouse, but it sounds better than Raytheon's. You're absolutely right, the clear top 6EW7 has got loads of detail and sweet mids. Since I'm using Edition 9, the bass is just about right. I prefer them to all the 6DE7s and non-clear top 6EW7s I've got.