small question about coupling caps

[dschwartz]

Hi there...
i have a small question about frequencies affected by a coupling cap on tube preamps...
i assume that the resulting filter is a product between the previous triode output impedance, next triode input impedance and the cap itself..

is there any way i can calculate the corner freq?

[GibsonGM]

I'd assume using the standard formula F=1/2pi*R*C works  ..... but you would have to have the other information.  Maybe you can get close from tube data sheets or running a simulation with software?  I don't think the Miller Effect would have much to do with anything, as it is very small, but the impedances would for sure, as you've stated. 
I approach this by either using known values, or 'plug and play' to see how cap changes are affecting stages. 
Good question.

[Gus]

http://www.aikenamps.com/

A site that has been on the web for many years.

[alfafalfa]

Daniel,

I use a small Exel file in which I can change the values of cap and resistors to get the right cutoff frequency.

If you pm me with your address , I'll send it to you.

Alf.

[dschwartz]

thanks!!that spreadsheet and aiken amps articles are simply wonderfull..