The ECC82 is a low μ general purpose double triode audio. The performance is good and this is often used in audio applications where high gain is not required or to drive a larger output valve.
The 6C4 has almost the same rating as half of an ECC82.
The logo on the glass is different to our other Pinnacle ECC82.
The twin triode sections. The central line is the support for the getter holder and not an electrostatic screen.
The thin glass tube envelope is 20 mm in diameter and the length excluding the B9A base pins, is 49 mm.
References: Data-sheet & 1040. Type ECC82 was first introduced in 1951. See also 1951 adverts.