[AMPS] Re: Poor Science

[Michael Tope]

Tom,

See my comments below.

Mike, W4EF...........


Tom, W8JI wrote:

Hi Terry,

Most people have names. If you are addressing me, use my name 
and I will answer.

I wouldn't call you Mr. Sucker, and in return I don't expect to be 
called Mr. Denial.

> I really question why I am wasting my time with this ... I hope this will
> be of interst to some ... I am sure Mr. Denial will will just consider it
> nonsence as he has with most all of Rich's claims ... But this is from the
> real world of what actually happens ....
> 
> The amplifier was in STANDBY ..... NOT KEYED .... but with all voltages ON
> ! I had a reason to remove the top cover (high voltage interlock removed),
> I slowly raised the cover from the front of the amplifier leaving the rear
> of the cover sitting on the amplifier ... when I got the front of the
> cover raised about 3 inches ... all of a sudden the amp made this huge big
> grunt and the circuit breaker tripped off. After I removed the top cover
> and turned the amp back on I had idling plate current in the standby mode.
> Long story short ... I had one of the two 3-500Z's with a grid to filament
> short and that tube had metal particles rolling around inside of it. Ten
> minutes earlier this amp was putting out 1300 watts on 20 meters. NOT
> knowing what had happened I replaced the bad tube and tried again. Guess
> what ... with the cover about 3 inches raised ... yes ... I lost another
> 3-500Z ! This was a damn expensive way of being introduced to the type of
> oscillation that Mr. Denial says can't happen !

The theory you are supporting is Rich's claim that a photon can 
strike the cathode of a tube that is on standby, and cause enough 
current flow to arc over the relay contacts and put the amplifier in 
an operating mode.

Once in the operating mode from the wayward photon, the amplifier 
that was OK for weeks or moths before (with the very same relay 
closed and opened hundreds of times) now suddenly has a 
parasitic and draws so much current it actually explodes the 
elements inside the tube.

I'd like to ask a few questions:

1.) What type of amplifier was it.

@ I seem to remember pictures of a homebrew amp on Terry's website, 
but he of course can best answer that.

2.) What type of tubes.

@ Tom, I think Terry answered that, 2 x 3-500Z

3.) Why don't the photons generated in normal operation cause the 
same problem?

@ As, W8IK points out, this failure doesn't appear to be random. Terry's description
implies that the cover movement (3" lift in front) is the causal element in the
catostrophic failure. The fact that this happened twice implies a systematic and
repeatable phenomenon (perhaps lifting the cover sets up a cavity resonance with
the correct amplitude and phase to sustain an oscillation).

4.) Why don't photons in gas-filled tubes specifically designed to 
detect photons have even modest amounts of current?

@ Won't argue with you there. PMTs have very large gains, and are generally followed
by pre-amps. 

5.) Why do hundreds of other amplifiers without covers not fail?

@ If I am not mistaken Terry's amp is homebrew. This could be a unique geometry.

6.) Since the saturated current of a 3-500Z is about 10 amperes or 
so (that's all the filament can "give up", even if you hold the anode 
and grid at 3000 volts positive), how does the oscillation cause 
enough current to shatter the filament or grid?

@ I have no idea!

7.) If the tube could supply that much current, how does it get that 
current so fast through the high surge impedance of the path from 
the energy storage area (power supply) into the tube?

@ Ditto!

If you have no explanation other than blind faith, then I can accept 
that and respect it. I never argue religion.


 
73, Tom W8JI
w8ji@contesting.com

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