The 30A5 is a power audio output pentode designed for operation with low anode voltages and in transformerless designs. It can deliver 2.1 Watts at 11% total distortion
The anode, stitched at the sides, hides almost all of the inner grids.
Here the tops of the grids supports can be seen indicating a true pentode.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 59 mm tall.
Reference: Data-sheet. Type 30A5 was first introduced in 1956. See also1956 adverts.
