Post-PI gain

[lowell]

Anyone ever seen or implemented post-PI gain stages? I'm thinking a gain stage and then cathode follower after the PI to drive the power tubes. Reason for this thought is to overdrive the power tubes more without needing to mess with PI Ra/Rk values. Just curious.

[defaced]

I've only played with AC coupled cathode followers, which are no good. I'm currently working on direct coupled MOSFET followers, but results are TBD. There's a thread on it titled "Clairification on MOSFET Follies" in the theory section. R.G. has been a great contributor and there's a load of info in the thread. There's also an old thread on driving power tubes into AB2 which is worth reading. It's long, but many different methods for driving the power tubes are discussed

[lowell]

D,
Why didn't you like the AC coupled followers?

[lowell]

ok just read your other thread. The AC coupling negates ridding of coupling caps and grid blocking.

[defaced]

From my end, I can hear a limit in power with the AC cathode followers. I mean the difference between "not loud enough for the drummer" and "I don't hear no stinkin drummer".