Many DIYers discovered that TV dampers are well suited for rectifier use and outperform most of the 'standard' rectifier tubes. Their main drawback is the need for two tubes for a full wave rectifier since they usually only come with one diode inside. There is one exception however: The 6BY5.
This tube has two individual diodes in one bottle. Common rectifiers have two plates and a common cathode while in the 6BY5 the cathodes of the two diodes are also separated, only sharing the heater.