[Moon-net] filaments

[Peter Voelpel]

Hi Keith and the group,


I guess most of the unreliability of the TA1800 was caused by the servo
system


What Valvo explains in their transmitting tube data book about the use of
thoriated tungsten heaters:


1. heater voltage should be kept as exact as possible to +/- 1% maximum 

2. in standby periods heaters should be kept on up to 12 hours for large
tubes, up to 2 hours for smaller tubes

3. during those standby periods heater voltages can be reduced by 20%


73
Peter    


-----Original Message-----
From: moon-net-bounces at list-serv.davidv.net
[mailto:moon-net-bounces at list-serv.davidv.net] On Behalf Of Keith Naylor

Designed well before people paid too much attention to the caring of
thoriated-tungsten tubes.
(BTW, the Eimac spec is 7.5V +/- 0.37V)