The 6H9C is a Russian copy of the 6SL7GT and is a medium impedance double triode with high gain. The valve has twin triode sections for use as AF voltage amplifiers, phase splitters and where required as a cascade amplifier of very high gain.
On the base cap is the smudged lettering of OTK - indicating a military product.
The twin triode sections with separate cathode connections.
Side view with the reverse of the logo etched into the envelope.
The wide glass tube envelope is 28 mm in diameter and, excluding the IO base pins, is 63 mm tall.
