The Marconi companies were named after their famous founder, Guglielmo Marconi. He was an Italy, but he established and operated his company in England.
The grey glass version is usually regarded as tubier sounding: a bit sweeter, richer, and warmer. The KT66 did go through a few changes with it's oxide plate coating, which probably explains the differences in sound (likely has little or nothing to do with the graphic coating on the glass).
The grey glass version is usually regarded as tubier sounding: a bit sweeter, richer, and warmer. The KT66 did go through a few changes with it's oxide plate coating, which probably explains the differences in sound (likely has little or nothing to do with the graphic coating on the glass).