In Reply to: This has nothing to do with ego posted by Tim on January 06, 2003 at 07:30:34:
One example of such a tube is the EML 45, which is significantly better than earlier versions. There are numerous examples of tubes where a 1950's version sounds significantly better than a 1940's version - Tungsol 12AU7, Sylvania 6SN7GT (the 1952 bad boy is hugely better than the earlier VT-231), Raytheon 6SN7WGT (better than earlier VT-231's to me), and so on.
But with the exception noted above, and the GEC KT-66, I have never - ever - heard a 1960's or later tube that was near as good as it's pre-1960 counterpart.
The getter shape has no determining effect on sound. None. It's a getter halo.
The shape of the getter DOES identify relatively reliably the period of manufacture, pre-1960 usually being D-getter, post-1960 being O-getter, with a few exceptions both ways.
This is useful in that there is a very large chance that a pre-1960 - being D-getter to identify - will be a better sounding tube.
As to why, I'm no expert. I suspect several factors, among them being quality of materials, higher production post-1960 at lower cost, the reduction in military purchasing, foreign competition at lower cost from 3rd world countries, and the decline in tube usage.
i haven't posted in a long while, just content to be lurking. audio mania has settled down a lot :) i've moved to another part of the country and a new job. i used to share my computer terminal with a bunch of audiogeeks at my former work, and i think i know who posted the flame, but it ain't me, sorry. (don't even know if this registered moniker still works).
But I'm still way more expert than you, mr. shadow coward from Hong Kong.
As to understatement of the year - the year is just starting. I'm sure you'll trump me quickly.
Thanks for the input. It is examples like these which provide us with the limitation and caution to any generalisation.
As for GEC KT66, there are indeed no version sound better than the earler ST bottle black base KT66 (aka VT75) with either clear glass or smoked glass. And the black base smoked glass GT version also sound better than any GT GEC KT66.
However, in my personal experience, the brown base smoked glass GT version GEC KT66 actually sound worse compare to the later brown base clear glass GT version KT66 with cup getter as well as the latest brown base clear glass GT version KT66 with circular getters.
Why this is the case always remains a mystery to me.
And indeed the shape of the getter itself means nothing, except as a means to identify the vintage of the particular tube from a particular manufacturer, which matter a lot.
Of course, the degree of difference between different vintage also varies depends on tube model and manufacturer.
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