Mullard Amplifier Project

[pamphonica]

According to a friend who worked at Mullard, the yellow print was indeed for the Jubilee year. They wanted gold but had to settle for yellow once the bean-counters found out the relative costs.
But they had a lot of the yellow paint left over afterwards, so ended up using it from time to time in subsequent years whenever stocks of standard white temporarily ran low.
There was never anything "special" about yellow print valves after all!

Jeremy