EMRFD Message Archive 3275

Message Date From Subject
3275 2009-06-30 12:56:34 Ashhar Farhan JBOT - Just a bunch of transistors as a linear amp.
I just finished posting a low power linear amplifier that I have been
playing around with.
Here is the link http://www.phonestack.com/farhan/jbot.html

Though I have documented the circuit with FT 37-43s, I haven't build a
version with them. I hope someone builds one with them ...

- farhan
3277 2009-06-30 13:35:30 Chris Trask Re: JBOT - Just a bunch of transistors as a linear amp.
>
> I just finished posting a low power linear amplifier that I have been
> playing around with.
> Here is the link http://www.phonestack.com/farhan/jbot.html
>
> Though I have documented the circuit with FT 37-43s, I haven't build a
> version with them. I hope someone builds one with them ...
>

Nice design, especially the inclusion of the emitter degenerating
resistors in the final so that you don't have to go to the trouble of
matching transistors. And nice usage of series/shunt feedback in the driver
stages.

I might substitute an additional 2N2218 and series resistor for the
diode so that the biasing tracks closely with temperature.

Chris

,----------------------. High Performance Mixers and
/ What's all this \ Amplifiers for RF Communications
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
_
3477 2009-08-15 05:19:21 drmail377 Re: JBOT - Just a bunch of transistors as a linear amp.
3478 2009-08-15 06:36:41 Ashhar Farhan Re: JBOT - Just a bunch of transistors as a linear amp.
david,

you could use two stacked FT37-43s i am told (i havent personally used
these). you can find quite a few pictures of the tv balun on the bitx
group. here is one picture from my site
http://phonestack.com/farhan/balunpic.jpg . you can directly mail me
on afarhan@gmail.com to avoid 'noise' on the group.

- farhan