The 5654/M8100 is the special quality version of the 6AK5. It is an wideband RF amplifier pentode for VHF and above. The rugged construction is to allow the valve to operate in situations of vibration and knocks.
The pressed one piece anode is stitched at the side and fixed to the support. The anode is reduced in area at the ends and so the three grids can be observed.
The connections from the base pins are made with copper ribbon. The anode connection is shielded down to the centre of the base.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 37 mm tall.
References: Data-sheet & 1040. Type 5654 was first introduced in 1948. See also1948 adverts.