THE GREAT MULLARD MAGIC BLOG — valve base wires

Today, I want to look at LEAD IN WIRES.   Look in any PINCH & FOOT valve and you can see the LEAD IN WIRES sandwiched on all sides by the pinch glass.  In order to maintain that seal, the wire has to have a similar coefficient of expansion as the glass surroundings - a tall order indeed! In actuality, the LEAD IN WIRES are of a composite construction with the top section being of sufficient diameter to make the electrode cage support rigid and similarly with the bottom section of copper wire that forms the valve pin connection.  The middle...