[AMPS] TL-922 Filament Transformer Protection

[Jon Ogden]

>> Boy now thats a parasitic I wouldnt mind having,  all the 
>> parasitics that I have seen , most of them around the 
>> 4-1000 amplifiers, cause damage to say the least.  When 
>> the amp takes off uncontrollably and meters bend around 
>> the pegs, resistors blow, safety trips explode, that what 
>> I call damage.  
>
>Sounds like you have confused outgassing or gas ingress, a fairly 
>common occurrence, with a parasitic.
>
>High vacuum arcs are  common in tubes, especially old used glass 
>tubes.
>
>I guess if we don't know what a problem is, it's easy to call it a 
>"parasitic".

I disagree, Tom.  While some parasitic oscillations in amplifiers are 
well behaved, some are not.  In my 4-1000A, for the longest time while 
building it I had a slight oscillation that I could produce every time I 
brought the tune C to minimum.  No bangs, arcs, etc.  

However, at one point I was dealing with a cavity resonance.  The amp was 
stable w/o the cover.  Once I put the cover on, I got a big bang and it 
wasn't from any gassing.  However, these sort of events are typically due 
to some other problem such as a bad layout (the orignal problem in my 
amp) or some other failure.  I would venture in a "normally" working amp 
that big bang parasitics don't occur.

And to comment on the point that Rich has said he's never seen arcing 
from a badly loaded amp:  All I can say is BEEN THERE!  DONE THAT!  I've 
had mine mistuned once or twice and heard some real nice arcing.  And I 
have a load C with rather large plate spacing.

73,

Jon
KE9NA


-------------------------------------
Jon Ogden
KE9NA

http://www.qsl.net/ke9na    <--- CHECK IT OUT!  It's been updated!!!!!


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


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