THE GREAT MULLARD MAGIC BLOG — grey glass tube
WHAT'S INSIDE A VALVE (viii)
Posted by STEVE M on
Today, I want to discuss INTERNAL CARBONISATION sometimes also referred to as screeding or colloquially as grey glass. From preceding blog articles, I have already explained that electron emissions are drawn from the cathode to other positive electrodes within the cage and sure enough, the majority of emissions do travel within the electrode cage, however, like recalcitrant small animals and wilful children, a small proportion don't do what they should and escape from the electrode cage striking the glass envelope walls. These 'loose' secondary electrons can build up a potential charge on the glass which can cause audible distortion and sometimes a...