>
>Hi all,
>I just put filament voltage to my new 8169 tube for a
>little burn in time.
>To my surprise, the filament appears to drawing about 48
>or 49 amps instead of the data sheet 42 amps with 9.00
>volts at the socket.
>Should I be concerned? tungCould this be the norm for a new
>tube, then after a few hours, it will drop back to the
>42 amps?
The opposite is the case. As a tube ages, the tungsten carbide layer is
slowly replaced by (less-resistive) pure tungsten and fil. R decreases
slowly - thereby causing filament current to slowly increase. . If
you are sure that this tube has low hours, perhaps the filament is
somewhat atypical.
cheers, Bruce
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|