[AMRadio] New Project

[Kim Elmore]

I love projects like this! I need to make more time to ay with them. I say go for it!

Kim N5OP

On Oct 15, 2011, at 12:58 PM, "John Coleman" <jc at pctechref.com> wrote:

> Well there will be many folks that will say "why bother", but I have a
> little project in mind that I have been discussing with Geoff, W5OMR.  It is
> just a little fun and learning project.
> I want to build a push pull class C rig using a single 6SN7.
> 
> Max Plate Dissipation is 7.5 watts for both sections or 5 watts for each
> So I plan to dissipate about 3 watts per section
> 
> Peak voltage rating is very high on the 6SN7 as is the peak current -
> something like 1200 volts and 300mils.
> 
> I think I will run each section it at 400V on the plate and 30mils of plate
> current.  That's 12 watts input per section or 24 watts input total.  This
> should yield about 18 watts output.
> 
> The load reflection from the Tank is calculated 
> Lz = Eb/2Ib = 400/.06 = 6666 ohms
> 
> I'll figure the tank circuit from that later.
> 
> At 400 Volts Eb, the charts show cutoff at about -30 to -40 volts grid bias
> 
> Class C is usually biased about 3 X cutoff so I will apply -100 to -120
> volts regulated to the grid RF choke and drive it till I get max output at
> 60 mils plate current and then about 1.2 times more drive from my
> experience. And then measure the grid current.  I'm expecting it to be about
> 5 mils of grid current, but that is just a guess.  I'll calculate a grid
> leak from these findings for later use.
> 
> Anyone got any other ideas or experience with these little triodes as class
> C devices.
> 
> John, WA5BXO
> 
> 
> 
> 
> 
> 
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