Re: Filter problem

On Sun, 15 Jun 2025 19:38:33 +0200, Gerhard Hoffmann <dk4xp@arcor.de>
wrote:

Am 13.06.25 um 22:54 schrieb john larkin:
>

There is an inductor in the anode circuit, which resonates with the
valve capacitance (and a trimmer) at the output frequency.

>

There's no Miller effect only if the grids are zero impedance to
ground at 150 MHz.

>
There is no Miller effect when there is no voltage gain between
grid and anode that could be fed back via Cga. A shorted grid
just shorts the feedback.

Sure. Miller needs gain.

There is also no feedback when input
and output frequencies are really different

How does the Miller effect know what the input frequency is? Does it
disappear when there is no input?