Re: Transistors

On a sunny day (Sun, 18 Nov 2007 09:09:36 -0800 (PST)) it happened Winfield
Hill <hill@xxxxxxxxxxx> wrote in
<c6715fdf-9c29-4f67-a00b-6e0279b827a7@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>:
I was sort of looking at a different output a bit like your class A,
ftp://panteltje.com/pub/amp1.jpg

This is classic and has about 50 Ohm output.
Have only simulated DC... have to finds some transistors.
Wha tdo yo uthink of the output stage?
(Never mind the rest I just filled in what I felt like).

That's a good example of a circuit that will get into
serious trouble above 100kHz or so... No good way to
rapidly turn off the unused transistors.

......OK, :-) if you say so.

Oh well, I had to import some Zetex spice models in swcad, and
these are not the ones I want. I get 30 degrees phase shift at 10MHz,
with 250MHz ft transistors, there are much better ones.
Removed some stuff too (makes little difference).
ftp://panteltje.com/pub/amp1_ac.jpg
It does not have so many, what do you call it, 'ripples' as that chip.
I am sure with the right transistors this will do 50MHz.
Actually I used it in the past several times.... for other things.
So what do you have against that configuration?
This is with lower emitterio resistors:
ftp://panteltje.com/pub/amp1_ac2.jpg
.