Tube filiment voltage ???

[Harry Bissell]

     I remember (well I read that... I'm not THAT old...) that ENIAC
used a reduced filiment voltage to prolong the life of the tubes so that
the MTBF would be acceptable.
Not that the tubes were unreliable... but with that many tubes in one
place its a done deal that one is (statistically) sure to die at any
time.

   Other hand I've heard it said that this was done just to reduce HEAT.
Thousands of tubes would do that also...

Any audio reasons to give this a try ??? Neat new sounds ??? Waste of
Time ???
:^) Harry