[ARC5] Plate impedance...

[WA5CAB at cs.com]

Brian,

No insult intended.  Where I grew up in the late 40's and 50's, kids and 
soldiers referred to almost everyone by their last names, a practice that that 
generation and the ones that preceded and followed it continued at least well 
into the 80's.  With the appropriate prefix in the case of kid to adult.  I still 
often do it after 60+ years.

I didn't go back and re-read Ken's original question and when you questioned 
my arithmetic and inquired as to whether Ken meast one tube or two.  I simply 
assumed Ken hadn't said or you wouldn't have asked which he meant.  And 
although the plate characteristic curves for the 807 and 1625 do go up to 490 mA, 
maximum signal plate current for AB2 is 130 mA and for all of the Class C 
services 100 mA max or less.  If you decide to operate a single 1625 at 550 mA, I 
have plenty of replacements to sell you.  :-)

As several comments since indicate that several of the commenters didn't get 
the distinction between what Ken asked and what he may have meant to ask, the 
equations that Dennis posted are not for determining the output impedance of 
the amplifier tubes but the optimum impedance of the attached tank circuit for 
maximum overall efficiency.  The plate impedance in Ken's scenario is as I 
said, 3666.67 ohms.

In a message dated 12/15/2008 1:36:27 PM Central Standard Time, 
kgordon2006 at verizon.net writes: 
> On 15 Dec 2008 at 19:05, Brian Clarke wrote:
> 
> >Excuse me Robert,
> >
> >Not so dismissive, please!!! Referring to a person by surname is an
> >insult in most countries I have visited.
> >
> >The originator of this thread asked:
> >
> >Anyone know what the plate impedance is of a pair of 1625 
> >at, say, 7.0 Mhz, a plate voltage of 550 VDC, and a plate 
> >current of about 150 mA?
> 

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480
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