[AMRadio] filament voltages


Rbethman rbethman at comcast.net
Mon Aug 16 15:30:14 EDT 2004


Too low of a filament voltage WOULD be detrimental to the tube life, BUT 
reduced PLATE voltage while maintaining full filament voltage WILL 
extend the tube's overall lifespan.

That's an area that I agree with Don completely!

It's the one place that variac use on start up of an older stored rig 
can give you problems.  The rectifiers are functionally out of whack.  
Solid state "temps" would be wiser during that stage.  Or even reform 
caps with an old heath cap tester.  It has multiple voltages to test 
them with.

Bob - N0DGN

Donald Chester wrote:

>>
>> A while back, you said something about running too little voltage on 
>> the older
>> big jugs, like 833's, 250THs, 4-1000's, etc...
>> Of course, we know that running voltages that are too high will kill 
>> the life
>> expectancy of the tube, by why is running too little voltage bad for 
>> the tube,
>> if it's developing full emmission at a lower voltage?
>
>
> I think low voltage would be ok as long as you are not exceeding the 
> current rating of the tube, starving the filament emission by running 
> too low filamrnt voltage, or exceeding the rated plate dissipation.
>
> Don k4kyv


-- 
<                      Bob Bethman - N0DGN
+-------------------------------+----------------------------------+
| N0DGN AMRadio Manassas, VA    |    REAL Tube Radio and AM        |
+-------------------------------+----------------------------------+
|       Manassas Radio - Home of Homemade Kielbasa & Pirogi        |
+-------------------------------+----------------------------------+
| Bob Bethman                \\\|///     " The absence of a danger |
| rbethman(at)comcast.net   \\ ~ ~ //      signal does *NOT* mean  |
|                           (/ @ @ /)      that everything is OK " |
+-------------------------oOOo-(_)-oOOo----------------------------+
|               <http://home.comcast.net/~rbethman>                |
| 1 BC-610I w/BC-614I,1 T-213/GRC-26 w/BC614I 1 '51 Collins R-390A |
| 1 '67 EAC R-390A, Heathkit DX-60, Apache, Mohawk, SX-101, HT-32A |
+------------------------------------------------------------------+
|           Amateur Astronomer - Celestron Nexstar 8               |
|             12" f5 Dob coming soon!  Being built                 |
|                  Meade ETX-60 (Got it back!)                     |
|               38 Deg 46.8' N - 77 Deg 28.5' W                    |
+------------------------------------------------------------------+
|   Opinions expressed are that of my own and do not necessarily   |
|         coincide with or represent those of ANYONE else          |
+------------------------------------------------------------------+
  ALL E-mail received and sent scanned by AVG & Norton Anti-Virus>






More information about the AMRadio mailing list

This page last updated 17 Nov 2017.