Thanks Steve that is very useful.
Regards
Conrad
On 22/08/2017 21:48, Steve Thompson wrote:
Some years ago I measured some valves, including 3CX800. I don't think
I have kept the results but the general result was that the C was
about twice the data sheet value, and wasn't changed by the mechanical
setup unless the metalwork was really close - much closer than you
would want when looking at a layout.
Steve
As I do not (yet) own a decent LCR meter does anyone have a decent
ball park figure for the stray C to chassis for a 3CX800A7? The side
walls are 1.25 inches away from the tube and the lid is 2.5 inches
above.
Also thanks for all the help with my previous questions. I should
mention that this is a retrofit to an existing 2m amp and C1 is 6pF
maximum and I would like to use this part if at all possible.
I have a design that works on paper for strays C of 4pF with a Q of 8
using an L-Pi-L configuration as recommended by a few of you. The 4pF
stray value does not seem unreasonable but it is a guess. I am sure
that someone must have measured this.
Regards
Conrad PA5Y
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