[AMPS] TL-922 Filament Transformer Protection

[Jon Ogden]

>>I also question whether
>>overheating of parasitic suppressors isn't down to them getting very hot
>>because of physically where they are, 
>
>€  In all but conduction-cooled and water-cooled situations, vhf 
>suppressors typically live in fast-moving air.  

That still doesn't mean that the resistors are at room temperature.  Fast moving air at 100° C still spells an ambient temperature of 100° C.  And the resistor's dissipation ratings are correspondingly lowered.

Rich, you've never ever responded and tried to defend your suppressors when I tell the story of how I thermally burned them up in my amp on 10M.  The 4 1 Ohm parallel combination you call Ra or the "anode fuse" burned up completely!  Now how can 0.25 Ohms of resistance with only 0.7 mA of DC current burn up when the power handling capability is greater than 6 Watts???  Easy answer:  circulating current + high temperatures.  And your LR suppressors desoldered themselves due to the heat even with silver solder.

No, none of this was parasitic damage.  After taking your stuff out, I've had nary a problem.

To your credit, I must say that your series RC cathode suppressors work very well and those did solve stability problems.

Fast moving hot air is still hot air.  It's true in an amp.  It's true on this reflector.

73,

Jon
KE9NA


--------------------------------------------------------------------------
The Second Amendment is NOT about duck hunting!


Jon Ogden

jono@enteract.com
www.qsl.net/ke9na

"A life lived in fear is a life half lived."


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