[John Frake]

I am designing and building a px25 class A amp, given the simplicity of the circuitry design may be an overstatement however I would like to use the 83 Mercury Vapour Rectifier. I am unsure about the need to heat the filament before applying 350V AC to the rectifier's anodes. Data sheets on the 866A are quite specific "no HT before a warm-up period" howver I can find no such warnings in any of my info on the 83. Does anyone have any information or experience of using this rectifier that they could pass on?

Regards

john