Question about "Instant On"

[old_tv_nut]

Originally Posted by rcaman

i think your wrong with the shortened crt life. i seen plenty of rca and zenith with instant on that held up better than the warm up cool off crt's. it is not like they are producing a picture in instant start mode it is just reduced filaments.
you don't see a picture on the screen thus no electrons being produced by the crt

Cathodes do not work the way you assume. They are always boiling off electrons if hot enough, to create a "virtual cathode" that is the source of the electron stream, which is modulated by grid and anode voltages. If there is no net current, electrons are returning to the cathode at the same rate as they are leaving.

[zeno]

Originally Posted by old_tv_nut

Cathodes do not work the way you assume. They are always boiling off electrons if hot enough, to create a "virtual cathode" that is the source of the electron stream, which is modulated by grid and anode voltages. If there is no net current, electrons are returning to the cathode at the same rate as they are leaving.

An old debate nobody ever won !
Personally IMHO instant on in an all tube set is a slow & painful
death of the rest of the set. Just a very bad idea. It dont matter if the tubes lasted longer or shorter.
On a solid state I dont care either way.
CRT's on Zenith flats lasted forever & RCA's did too. Most others
used GE, West., & Philco jugs didnt last but probably because of
the tubes & not the instant on.

73 Zeno