The 6CB6A is a short cut-off high impedance voltage amplifier beam tetrode. This exhibit has double mica sheets as would be required to confer vibration resistance to the internal structure.
The control grid support is copper and the two anode plates are joined by a strap visible on the left.
Looking along the grid axis the anode structure is clear to see as are the beam plates approximately two thirds of the distance between the cathode and anode.
The envelope is 17 mm in diameter and, excluding the B7G base pins, is 48 mm tall.
Reference: Data-sheet. Type 6CB6A was first introduced in 1957. See also1957 adverts.
