>>Well, I was only following what I read in both the ARRL Handbook and
>>W6SAI's book (including a c.1972 copy). It is amazing how unhelpful
>>most
>>of the literature is out there concerning amps.
>
>That particular amp was pbly never tested on 10M Jon! They have the same
>one in my 1981 edition but almost all the remaining amps use 3 resistors
>and 1/2" wide strap.
Perhaps some of the amplifier projects use the strap, however, the text
talks about a wire coil. And I went out and bought the latest version
just a couple months ago. Same stuff as the old one. Just a few
different amp projects.
>>So I guess I am a schlock designer! :-)
>
>I never said that Jon...
It was a JOKE, Carl! :-)
>Of course...I fully agree and that is what the suppressor should be
>designed for. It would also help if you could shift that frequency higher
>with lower inductance in the plate strap. In some cases you can try
>moving just the Suppressor R, no coil, along the plate strap and GDO for
>best position. Other circuits bend the plate strap into a small U and put
>the R across the open end.
Finally, we agree! Thought I was going senile myself!
>
>Mouser has no minimum $ order so it would be advantageous to pick up a
>handful of various value 5W metal oxide's.
Probably not a bad idea.
>
>
>> I don't know why we
>>can't agree with this.
>
>I think we do agree; just communication confusion!
That's what it seems like.
>>Depends on which side of the amp your tube is on. On the right side
>>of
>>my blocking cap is my supressor circuitry. On the left side is my
>>tank
>>circuit. So I am designing the supressor for the side of the circuit
>>that includes: tube, plate RFC, supressors, blocking cap and tune C.
>
>
>Huh? The Tune C is on the same side of the blocking cap as the tube????
No, it isn't. However, the tune C does complete the path to ground for
the VHF resonant part of the anode circuit. I wish I could draw on an
e-mail program! Then I would make sense. Let's just say we probably
agree here, too.
>
>More confusion again Jon. All I am asking is for you to explain how a
>parasitic has enough energy to generate a field to bend a filament.
>Nothing else.
I am saying is that IF an oscillation starts AND IF the output is fed
back in phase to the input of the tube, then you have a positive feedback
condition and signals COULD get very, very large. IF the current is
large enough, a large enough magnetic field could POSSIBLY be generated
inside the tube which could be strong enough to bend white hot wires.
That's all. Yes, it's conjecture. I offer no proof. I said it's a
possibility. That's all. I am just basing this on elemental first
principles (positive feedback, current creating magnetic field, etc.).
Perhaps something is wrong in my understanding of tube construction. I
haven't gotten that far yet. I am more concerned with finishing the work
on my amp before I dig into how a tube is constructed.
>
>>
>>Now, imagine that same sort of magentic force except instead of a 1.5
>>volt battery, you have a 6 Kilovolt supply with a capability of 2 amps
>>of
>>current. That's 12,000 Watts
>
>A 3-500Z runs at 3KV at 400ma typically. How did we jump to 6KV and 2A?
>The filament runs at 5V @ 15A and produces a magnetic field.
>A parasitic will not generate enough energy to bend anything...BUT a gas
>arc can. You seem to continually neglect the gas theory...why?
>
Ok, I screwed up. You said 3-500Z, I was thinking of a 6KV tube like a
4X1. The 2A figure was a guess as to what the instantaneous current
could be during an arc. It could be way, way off. Yes, you are right.
I have no facts to back up my conjecture.
I haven't purposely neglected the gas theory. In fact, please explain it
to me since I am not totally sure what it says. We've been talking about
parasitic oscillations and the possiblity of them bending filaments.
Enlighten me on the gas arc theory.
>
>> white or red hot metal is malleable and
>>flexible. I'll leave you to figure out the answer.
>
>Meaningless to the discussion IMO. I have no idea how malleable a white
>hot tungsten filament is...do you?
More melleable than when it is cool that's for sure.
>>Please tell me why? Tubes are very much like FETs. I fail to see why
>>a
>>failure mode in a solid state PA couldn't happen in a tube. The only
>>thing is tubes ARE more rugged and can take more abuse.
>
>
>Absolutely true. A FET junction will most likely be destroyed by a
>parasitic. The parasitic frequency is also often at LF.
This is true. Tubes also have parasitics at LF as well. Oscillation can
take place at any frequency. Neutralization of the tube typically
eliminates the LF oscillations.
I have seen FETs take off and fly at a frequency higher than what the FET
is operating at. It's all dependent upon the circuit it's in.
>
>>>
>>>I have zapped my share of SS stuff...it is a totally different
>>>scenario
>>>but I can see that with really no tube experience you use that
>>>example.
>>
>>Quote from a textbook as to why.
>
>Primarily since the SS device is a junction device and a tube requires a
>vacuum as the conducting medium. I just dont think it is wise to lump
>them both into one for the purpose of this discussion.
Let's disagree here. I don't think that the fact of wether or not one is
using a junction device of a valve changes the concept of parasitic
oscillation. Yes, the active device has a different structure and so the
circuit is different, but the fundamental concept is still very similar.
Yes, with a SS device, you don't have filaments that can get bent
regardless of how it happens.
>
>
>>>Yet you profess to accept a theory with no proof! That is strange
>>>behavior for a trained EE.
>>
>>Carl, do you know what the "Scientific Method" is?
>
>The rest SNIPPED since I don't have my hip boots on!
Calling the scientific method BS? So call my theory without proof a
hypothesis. There are lots of things I accept without proof: the
existence of a Supreme Being, that the sun will rise tomorrow, etc.
>
>Goto go outside and play yard work..too nice a day to waste here!
Not so nice a day here.....Overcast and rainy...
73,
Jon
KE9NA
-------------------------------------
Jon Ogden
KE9NA
http://www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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