"Arfa Daily" wrote in message


Agreed that *should* be the case, but the fact is that
the envelope of a vacuum light bulb remains substantially
cold in use,

Maybe a really low-wattage bulb. But at 50 watts and up, you won't
comfortably unscrew a hot bulb with your bare fingers.

whilst a 6L6's envelope will take the skin
off your fingertips after a few minutes use ...
Arfa