The DL82 from Osram is a double diode variable μ triode for use as detector, AGC rectifier and first audio voltage amplifier in broadcast superhet receivers. It was first seen at the 1947 Olympia show and was obsolescent by early 1951. The DH81 was similar and pin compatible but had a higher amplification factor and a higher ra but no vari-μ characteristic.
The triode is at the top with the two diode anodes below the central mica. Each diode anode is made from thin strip that is bent around a former to leave a circular space. The anode is then spot welded to a support
The triode anode is stitched together and ribbed for greater rigidity. The base of the grid can be seen.
The Marconi paper label . Both Osram and Marconi valves would be made on the same production line at M-OV and differentiated only by the paper labels.
The wide glass tube envelope is 32 mm in diameter, and excluding the B8B base pins is 56 mm tall.
References: 1040 & 4018. Type DL82 was first introduced in 1947. See also1947 adverts.
