Tube Characterization: 6dj8, 6922, 7308, E188CC

Thanks Hartwerger.

Joe's Tube Lore is really what stimulated my interest in tube characterization. In a way, you might consider it a classic.

In a vain effort to expand on that knowledge base I proposed an across the board characteriztion of this family of tubes and their sonic attributes. This was met with quite a bit of opposition and defense of Joe. The information I gained however was invaluable.

I suppose that I need to sharpen my communication skills as this new post was intended to steer clear of objective analysis (believe me I don't want to go down that road again) and focus more on the individuals perception of what good sound is.

Perhaps I will repost like this. "Why do you like tubes?" or "What do you like about tubes"

I have recently installed Amperex 7308 tubes based on the review in Vacuum Tube Valley issue 9 and this is what I found:

The bass is really excellent and well defined all the way down to what seems like the limit of my speakers (von schweikert VR4Jrs @ 23 Hz). The bass and mid-bass are tight and well controlled and the character and timbre of the instruments in this range are very realistic and musical. The midrange is somewhat liquid and I guess you could say palpable. The high end is sweet end extended and actually has some weight. It's a really great tube. I purchased the U.S. made pulled from military equipment, but they spec'd really well so I went for them. It seems that I have seen these with gold on the inside of the tube, but I don't know what this signifies or what effect it has on the sound. Overall a very lucid, musical tube with a consistency of sound quality (consonance)top to bottom.

My next foray will be with the early Phillips Miniwatt and the Seimens 7308 circa 1961 if I can find them for the right price. I've heard the Siemens vary greatly between early and late manufacture and I wonder if the Phillips do too.but Older just seems to sound better across the board.