5 Jun
2010
5 Jun
'10
5:05 p.m.
On 5 Jun 2010 at 19:42, William Donzelli wrote:
No - it is ham lore only. Many tubes lives will
shorten if the
filament is run below spec. In some types, life will drastically drop.
Okay, you made me go and get my 1942 "Radio Handbook".
In the back, with all of the ads, there is a 2-page spread from RCA
entitled "How to make transmitting tubes last longer". Number one on
the list is "Reduce filament voltage":
"For tube types using pure tungsten filaments, a reduction of only 5%
of the filament voltage doubles tube life. A reduction of 15%
increases it almost tenfold!..."
"For types using thoriated-tungsten filaments and oxide-coated
filaments, the filaments may be operated on the low side--as much as
5% below normal voltage--if the loading is light..."
Another scam perpetrated by "General" Sarnoff?
--Chuck