Knghifi, I doubt that you will find what you are seeking with the re-issue Tong-sols. Compared to the SED 6550's their bass is bigger, yet tight, mid-range a tad warm, and highs natural. The SED's are more linear and in the wrong amp they can sound clinical (just as the Tong-sols in the wrong amp can sound a bit too warm). I've never heard the GL reissues but from what I've read I would assume they are similar to the SED 6550's with a bit more warmth and extended highs, but that is a WAG.
FWIW, when I'm seeking greater clarity I more often than not go to the small tubes and find success.
Hope that helps a bit.
FWIW, when I'm seeking greater clarity I more often than not go to the small tubes and find success.
Hope that helps a bit.