Look at that thing. It is already painted Juliello — this is a very good sign. Steve Silverman sent me one of these Sawdust Regen kits a few years ago. I put it together this week for my nephew John Henry who is very interested in Morse and ham radio.
This is a regen that even I can love. It is simple, small and stable. 40 meters comes booming in.
Look at the schematic. Why haven’t we used that simple three-terminal AF amp IC before?
Get your Sawdust Gear here: https://breadboardradio.com/breadboardradio/Products.html
Why haven’t we used that three-terminal AF amp before? Because the TL431 is a voltage regulator IC! It’s using the voltage reference input as audio in, and the voltage being regulated as the audio out. I wonder how well it really performs as an AF amp? http://www.ti.com/lit/gpn/tl431
Thanks Mike. I had never seen a regulator used as an AF amp. Check this out: http://theradioboard.com/rb/viewtopic.php?t=6733
More on using a TL431 as an audio amp: http://techlib.com/electronics/audioamps.html#TL431
TL431 as audio amplifier http://www.sm7ucz.se/TL431/TL431.htm