Quote:
Originally Posted by paulsherwin
There was a large element of marketing creativity behind these terms.
|
I've long suspected that marketing was behind the designations of the KTW61 and KTW63- on circuit diagrams, they are invariably shown as pentodes and, as far as can be made out through the inner-coated glass, they are indeed constructed as such. If I could bring myself to sacrifice one....(and they are pretty common, after all). The W61 is listed as an "equivalent" of the KTW61- it would be interesting to closely compare the electrode structures of these two, they might be very similar indeed!
Perhaps the success of the KT61, 63, 66 etc. (and the latter in particular) led M-O V to feel that "KT" had become enough of a symbol of success that it was now almost a brand in its own right and was applied to valves where it was not strictly technically relevant. Pressed on the issue, a company spokesman might have responded that a pentode was indeed a form of kinkless tetrode, though such an argument would hold more water in the case of valves with internal suppressor-cathode connection- the small-signal "W" types having separate cathode and suppressor pins.
Which reminds me- the 6F6 (a pentode) is quoted as equivalent to the KT63, perhaps the latter is also a pentode. Another case of sacrificial duffer required.