Two new bases appeared, the acorn tube and the lighthouse tube, both solving the same problems but with different approaches.

Acorn- as well as Lighthouse tubes and Nuvistors attempt to minimize this effect by arranging cathode, grid(s) and anode as closely spaced together as possible.

He'd tried six incompetent junior engineers before the last one, a brilliant chap named Spence, who seemed to be the only one of the lot who knew a lighthouse tube from a stub support.

A different approach was taken by the designers of the lighthouse tube, such as the octal-base 2C43, which relied on using concentric cylindrical metal contacts in connections that minimized inductance, thus allowing a much higher frequency.