QST, Dec 1970, p. 5.
QST, Mar 1971, p. 5. (good description of differences with 3k.
2K-4A
QST, Jan 1979, p 1.
QST, Jan 1980, p. 1.
The 2K-4 linear used the same 3-500Z final tubes as the 2K-3 but received a style makeover in the form of a tilted RF deck atop the floor console.
