[Amps] tube impedance, figuring tank circuit values

TexasRF at aol.com TexasRF at aol.com
Fri Mar 31 11:40:12 EST 2006


 
BTW, on the discussion of k=1.8 vs. 1.87 in the calculations: There is less  
than 4% difference between these two values. The difference can be covered by  
only a small "tweak" of the loading and tuning controls. 
 
This is not a real design issue. When we tune an amplifier for maximum  power 
output plus a tad heavier loading, we are tuning out all of these little  
design variations. What with the inductors being tapped at one turn intervals we  
are not going to hit the design impedance exactly on target anyway. 
 
73,
Gerald K5GW
 
 
 
In a message dated 3/31/2006 10:22:21 A.M. Central Standard Time,  
gpatterson53 at hotmail.com writes:

ok....  one guy says use the "open circuit voltage" the other guy say use the 
 
loaded "operating voltage" ..................who is  correct


>From: "Phil Clements"  <philc at texascellnet.com>
>To: "'Partain, Chuck'"  <Chuck_Partain at maxtor.com>,<amps at contesting.com>
>Subject:  Re: [Amps] tube impedance, figuring tank circuit values
>Date: Thu, 30  Mar 2006 16:20:27 -0600
>
>
> >
> > So, when I  power up my amp, I see 3910vdc on my plate. The way I have it
> >  configured, I put 330vdc on the screen grid
> > and -130volts on the  control grid., when I bring the control grid to 
>-69v,
> > the  tube pulls current. The voltage on the plate is
> > dropping to ~3600  to 3700. Is this the value I would use to figure the
> > impedance of  the tube for tank calculations?
>
>
>No, the voltage and  current of the amp when it is running at what you plan
>to operate it at  are the values that you plug into the formula. Say that  
>the
>voltage drops to 3500 volts at an operating anode current  of 1 amp; your
>tank should be configured for that, not the resting  anode I.
>
>(((73)))
>Phil,  K5PC
>
>
>
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