[Amps] Need Smarter Than I Am Help.

[Joe]

As many of you here know, I have been making some MAJOR changes to this 
Heathkit SB-220 amp.

Many here, and many other places, have helped me both on these E-Mail 
lists as well as directly.
I am extremely grateful for all this help!
These awesome people have given this guy that sometimes just does not 
understand something a LOT of help.

I won't waste space here, unless people here want the details.

But I need help with the final last steps on bringing this AMP back to life.
The AMP works, I just want to make sure it is working correctly or in 
it's best way.

The help I need with is because of the last major change I have made to 
this amp was the High voltage section.
It is totally re-built, with a Major change. The High Voltage is now 
roughly 3600 volts.
This increase of voltage has thrown The Pi-Output network all out of 
whack, because of the Plate load impedance has changed sooo much.

So the first thing I want to confirm, is my calculated value of what the 
plate load resistance
will be for a pair of 3-500Z's running at that voltage. For when running 
the reverse path output network testing.
You know, lift the plate caps off the tubes, and at their common 
connection where the two parasitic suppressors join,
Run this value of resistance to ground. Then you can activate the T/R 
relay, and using a VNA, or like an antenna analyzer,
you can actually adjust the Pi-Output network to get a min SWR, so now 
you know where the whole system matches and is happy.

Obviously to make this test meaningful, I need to be positive, what the 
value of the resistance to ground should be.
So Looking for these second opinions of what that value should be. And 
if you wish, explain how you got that value?

Now, at least that above question, I am fairly confident on the value I 
have calculated is right,
or at least close enough it won't make that much difference.

But this next one, or two, kind of co-related, I am 100% confused about. 
A few have tried to help,
but it is like they are speaking a space alien language.

OK the amp has Standard old Eimac 3-500Z's a pair of course.
Stock Caps on both Plate and Load.

The Inductor Now is a 0 to 18uH Roller Inductor.

The output side of the bandswitch, the ONLY thing it does now is to add 
the C56 Cap to ground when on 80 Meters.

Now here is the confusion.

I have had Tube gear all my Amateur life since 1975, Drakes, Heathkits, 
etc. And amps, Drakes, Heath's, Henry's etc.

And when tuning them up it has always been that the Plate cap amount of 
"C" always depended on the frequency of use.

On 10 meters it was hardly any "C" at all. And as you went down in Freq, 
you would have more and more "C" being used.

And that's the issue! On 10 meters, With that Roller Inductor, I can get 
a perfect SWR and I mean PERFECT, 1 to 1, Not even 1.01 to 1, but 1.00 to 1.

BUT..... and there always is a BUT isn't there?

I can get this perfect match, with a Plate load Cap fully un meshed (min 
capacitance) and easily as far as 50% meshed (like where it would 
normally be for 40 meters) and anywhere in-between! just by using a 
different amount of "L".

What is the "BEST" setting? I mean it is a perfect match, but running it 
with the cap like it would be for 40 meters doesn't seem right even tho 
the match is perfect.

So then I am told this is correct, but it all depends on the amount of "Q"

UG! "Q" This I have spent countless hours trying to understand and still 
can not seem to grasp what "Q" is?

What makes a "Q" of 10 a "Q" of 10.

If you want a different value of "Q" What do you change to make the "Q" 
change?

How about even a simple question,,  How do you measure to learn what 
amount of "Q" is happening?

And I guess a Important question,,, What level of "Q" does someone want 
to have in an AMP like this?

I hope someone is willing to try to help this old fart to try to either 
understand this, or at least help me be an appliance op and just get it 
set right so I can use it safely for the amp he he he.

Anyone?

Joe WB9SBD