>
>>>>? Tuning the HF tank circuit and disconnecting the hf load have
>>>>virtually nothing to do with what is happening in the anode-resonant
>>>>circuit where the parasitic oscillations take place.
>>>
>>>Ah contrair! You yourself have said that the anode-resonant circuit is
>>>composed of Ctune. Is not Ctune in the tank circuit???
>>>Sooooooo.......tuning the tank circuit DOES make a difference.
>>>
>>? Adjusting C-tune makes little difference in the anode resonance since
>>C-tune is effectively in series with C-anode, which is much smaller.
>
>Not necessarily, Rich. In many, many tubes .......
>
? What is the anode-resonance when your amplifier is tuned to 10m? .
. to 80m?
thanks.
>Additionally, I've always thought that Canode was the capacitance from the
>anode to ground. Ctune is also connected to ground. So I fail to see how
>Canode and Ctune are in series.
>
? one end of C-anode connects to C-tune through chassis gnd. When
viewed from the ungrounded ends, these two caps are in series and they
are in parallel with the interconnecting lead inductance.
>And when Ctune is rotated through its value we aren't trying to change the
>resonant frequency of the anode.
? In practice the resonant frequency typically exhibits little change as
C-tune is adjusted.
>What we are doing is rotating a reactive
>load around the Smith chart.
? In cases where a C-tune internal resonance happens to be near the
anode-resonance (AL-80, SB-1000) the test may produce an oscillation. .
A better test is to provide a continuous string of anode current pulses
that are passing through the anode-resonant circuit and creating a string
of damped-waves.
>
>How can you prove to me that a test is useless that so many others
>including myself have used to find out wether the amp oscillates?
? In my opinion, the test is not a fool-proof way of starting an
oscillation.
>Please don't minimize the legitimate experience of countless others.
>
>If the value of Ctune makes no difference
? Did I say this?.
>.......
>
>>>...... and the amp was completely stable.
>>
>>? 'Tis hardly a good idea to tempt fate this close to the ides of April,
>>Jon.
>
>Not tempting anything. If an amp is STABLE it is STABLE. That is why it
>is called STABLE.
>
? Famous last words:
"The Titanic is unsinkable.". .
"This amplifier is perfectly stable."
"This tower is so strong that it can not be blown down by any windstorm."
. .
- cheers
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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