The E83CC is a special quality ECC83 high impedance amplifier double triode that was designed specifically for audio use and has a high amplification factor of 100. The E83CC is a modern implementation of the specification by a Chinese manufacturer.
The role of this double triode is as low level amplification and as a phase splitter so that the push-pull output stage can be driven correctly.
The two sections are separated by a screen but I can see no electrical connection to it. The anode is wider than the ECC83.
One anode with the bright screen to the left.
The thin glass tube envelope is 21 mm in diameter and, excluding the B9A base pins, is 48 mm tall.