Kenrad JAN CKR 6B4G Power triode
The 6B4G is an unusual valve in that the envelope holds two triode valves that are hard-wired in parallel. This was the American answer to the PX4 and the parallel construction enabled the AC anode resistance to be the low figure of 800 Ohms. The device is rated at 3.2 Watts.
The 6B4 is a type 6A3 on an octal base.
The filament is coated ribbon formed into an inverted 'w' in both anode cavities. The grid is a wire zig-zag held on notched rods. The anode is formed of two pressed plates fixed together each with two half cavities. The anode cavities are 20 mm x 4 mm x 30 mm high.
The classic envelope is 48 mm in diameter and, excluding the IO base pins, is 111 mm tall.
The 6B4G was first introduced in 1937.
Ken Rad stands for Kentucky Radio corporation and was a very important valve manufacturer for The US government and defence contracts during World War II. Based in Owensboro Kentucky,In 1945 the company's valve division was sold to General Electric and became GE's primary valve making facility. In 1987, GE sold the company to a group of investors who formed a company called MPD, Inc