Philips (Netherlands). Valvo (Germany), Amperex (USA), Radiotechnique (France), Mullard (UK) , and Ibrape (Brazil) were all owned "country names" of NV Philips of Holland. Although each had their own manufacturing sites, after WWII, there was cross supply and support across the various markets, and innovation and manufacturing techniques were more freely shared. Indeed, no two manufacturing plants and processes were identical, but in a sense many of the tubes discussed here share a similar manufacturing heritage.