The ECC86 is very special high frequency double triode. At a time when AF power transistors were replacing valves but no VHF transistors were available the ECC86, used as the input stage, was designed to operate directly from vehicle battery supplies for car radio applications alongside transistors.
This is a Philips valve made in Holland. Our Mullard ECC86 exhibit looks the same as it too was made in Holland by Philips.
The two separate triode sections.
Here the depression in the anode wall is seen. The actual anode of the triode is the part at the far end of the depression, the rest of the metal is for heat radiation.
The Thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 48 mm tall.
Reference: Data-sheet Type ECC86 was first introduced in 1959.