Re: Tube TC plate/grid coils


The split tank tuning method might work well, but if the inductance
of the primary in a tube TC is reduced too much, the plate impedance
may change too much, and the tubes might get too hot.  Your idea
might be best for the final critical tuning, once the tuning is reasonably

For adjusting the grid feedback, the easiest way is probably to mount
the grid coil on a sliding sleeve that can be slid closer or farther from the
primary as you suggested.  I've been doing that on my tube coils for some
years now.  Adjusting this spacing will affect the feedback level, but a
change in the grid resistor has a different effect.  The grid resistor affects
the tube bias, the feedback level affects the overall drive level to the 
John Freau

> thanks,
>Grayson Dietrich >>