[Amps] GG tuned input with autotuner

[Randy S.]

Been awhile since I posted a question ..
Hope everyone is well ..
I have an Z-100 Plus autotuner.
GG amp without a tuned input
FT-897D rig

Situation is this:

Remembering what people said about Grounded grid amps without a tuned input
not being such a big deal if the rig was a tube output that you tuned the plate and load
as you were tuning / matching / providing the necessary flywheel effect ... 

Hope thats correct so far.

So I hooked up the autotuner near my FT-897D, solid state rig. About 10 feet or so from the amp.

Tuned up and all seemed well .. definitely more output .. 200 - 250 Watts more then without the tuner.

I also remember the chatter on the tuned input being IN the amp or attached with
as short a cable as possible .. so I moved the autotuner over to the amp and connected 

them together with about 8 - 9 inches of coax .. Try to tune up the same way I did
with the above configuration and not nearly the output .. 


So .. out of curiousity..  ( yeah I know ... meow ..  ) I put a longer length of coax
between the amp and the tuner output .. not sure how much .. maybe 10 ft or so..
About the same as was between the tuner and amp in the other config .. 

And .. viola ! The output came right back up again .. .

So .. whats going on here ?? inputs .. ( be nice )
The added capacitance of the coax per foot made a difference? 

Do I need some input loading caps to be added to the amp at the grids ?? 

I mostly run the amp on 80 - 20 .. 

Thanks .. 


Randy - N2CUA