Ultrone EH90 indirectly heated heptode frequency changer

The EH90 is an indirectly heated heptode frequency changer. In the early 1960's Mullard designed for television service in dual-standard sets, the EH90 as an FM demodulator for 6 MHz inter-carrier sound. There is a paragraph on the EH90 in the 'Mullard Outlook' in an article entitled 'New Mullard Television Valves'. EH90 - Sound Discriminator. Adoption of the 625-line standard is to include the use of FM transmissions, and the latest dual-standard receivers are equipped to accommodate these transmissions. The heptode, type EH90, is being used for FM detection in many of these new sets, where it operates as a locked-oscillator discriminator. The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 46 mm tall.