Summary

Triode heptode frequency changer. This, its side-contact equivalent ECH4 and its Loctal equivalent, ECH21 were unusual in that the triode grid was not internally connected to a hexode grid. This meant that the valve could be used for applications other than frequency changing.

6.3 V indirectly heated cathode, manufactured by Philips, Holland. In Australia this valve was usually called an ECH4G

Physical Description

Shouldered glass bulb on octal base with all pins present and top cap. Bulb has red sprayed coating as a screen.

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