.1 caps between PI and output tubes:Fender BF

[PCollen]

Hey guys, here's a very handy link: http://www.opamplabs.com/rfc.htm

As you can see, a .1 cap with a 220K grid-to-bias R gives you a high-pass filter that starts at 7 hertz! A .022 only brings you up to 32hz, which even a 15" woofer will struggle to reproduce. (snip)....

Put another way, the 0.1/220K establishes a -3dB freq of 7Hz and the .022/220K has 32Hz as the -3dB point. But keep in mind that the freq. roll off begins 10x higher.

[Jana]

Ken Moon said, "As my Grandpa used to say, "If we had some pineapple with this, we could make Hawaiian music"

I'm not sure why I find that so funny..."

Well, I thought it was funny! Not sure why either except it sounds like something grandpa would say just before he says, "pull my finger."

And then grandma looks over in disgust and says, "Uf Dah." And that makes it all the funnier to us kids.

Ah, the fond memories of childhood!

[C Moore]

Hey guys, here's a very handy link: http://www.opamplabs.com/rfc.htm

As you can see, a .1 cap with a 220K grid-to-bias R gives you a high-pass filter that starts at 7 hertz! A .022 only brings you up to 32hz, which even a 15" woofer will struggle to reproduce. (snip)....

Put another way, the 0.1/220K establishes a -3dB freq of 7Hz and the .022/220K has 32Hz as the -3dB point. But keep in mind that the freq. roll off begins 10x higher.

So, in your second equation, bass would start falling off at 320 Hz. Is that correct?
Thank You