Why doesn't this work?

[iknowjohnny]

I tried something last nite that didn't work and i'm not sure why. I tried to put a 1uf/470k filter after the .022uf coupler coming from one stage into the grid of the next. I have used the typical 470k/470P marshall style filter there and it works fine. But i wanted to see what would happen with a 1uf because i found i like the mids that a 1uf passes as a cathode bypass cap and i wondered if the roll off point would change if used in this different capacity or if it would give me a similar tone. i have never seen this done with anything bigger than a 470P or thereabouts, so i suppose theres a reason and that whatever it is must be why i wasn't successful. The problem it posed was that it created the same issue you have at a grid if theres no ground reference....that sputtering sound that gives way to no sound at all. But there WAS a ground reference resistor there, (a 220k) so tell me....why did that happen? is there a reason you can't do this with caps that are past a certain size? This by the way was NOT a polorized electro....it was a huge 1uf poly cap. I even measured it and it was indeed 1uf.

[Jana]

1 uf in one place will not give the same results in every place.

Seriously, take a little time and learn the math. It's not that hard. They invented calculators a few years ago too.

In most situations a capacitor can be thought of as a resistor that has a resistance that is dependent on frequency.

1/(2*3.12*f*C)

[KellyBass]

They also invented microwave ovens...by accident.

keep on wirin' and firin', johnny! There's a lot of things that work real nice that just don't work on paper.

[Andy Le Blanc]

don't be sore about it..... learning is doing.

The 470p/ 470k passes the highs thru the cap around the resistor.
with the 1uf your passing a greater range than the previous cap, you wont
hear a difference. Now according to your description I might speculate that
the size of the cap might have created a condition that blocked or canceled
the signal. With a little RC filter like that your shelving the response, I'd go
back and try anything from a .005 uf (5000p) to 50p and give it a listen.
I've used large caps like that as the input cap in a zero bias, bypass cap in the
plate and cathode circuits and signal output from a preamp, but haven't
tried that one. Usually stick with smaller values.

[iknowjohnny]

i get how it works and it should do what i expected if it weren't for that issue. i see no reason why that should have happened. After all, theres nothing on the output side of that filter that is HIGHER in level. It's a passive filter. so why should it cause any kind of blocking or whatever it would be called...cutoff?

[Andy Le Blanc]

there's a phase shift as the signal goes thru the cap, it'll be out of phase to a
certain extent with the signal that passes thru the resistor, enough to swamp the signal.
I'm guessing, but it sounds plausible.