>> 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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