it's definitely useful. I can see though that as the volume is set closer to minimum that it would affect it less as the impedance is dropping because of loading from the volume potentiometer. Oh also, you'd still benefit from adding bootstrapping to that transistor audio amp 😅
The initial audio input is adjusted by the 10k pot. Then is fed into the op amp and the 2nd 10k pot adjusts the feedback or cut attenuating the signal. Sort of like a corse and fine adjustment?
Why don't using the "classic" name for the circuit: Low Pass or Hi Cut... "Top cut"... lol. I believe the name is the result of Australia being upside down... :-)
Wow! I`ll use that circuit in my new homebrew cw transceiver.
Thank for video!
73
it's definitely useful.
I can see though that as the volume is set closer to minimum that it would affect it less as the impedance is dropping because of loading from the volume potentiometer.
Oh also, you'd still benefit from adding bootstrapping to that transistor audio amp 😅
Peter, you can use an 88uH inductor as a single component audio filter. It works well on CW.
Regards
Stephen G7VFY
Hi Stephen - I think you mean 88mH rather than 88uH. This large value is often difficult to obtain.
@@vk3ye yes you are right! I was looking for one to put in my improved pixie2. What I didn't realize, was how big and heavy they are!
Something to use on a next project.
Thanks.
73 de Pedro CT7ARQ
Simple and Wonderful
The initial audio input is adjusted by the 10k pot. Then is fed into the op amp and the 2nd 10k pot adjusts the feedback or cut attenuating the signal. Sort of like a corse and fine adjustment?
"Top cut" refers to cutting high frequencies?
Why don't using the "classic" name for the circuit: Low Pass or Hi Cut... "Top cut"... lol. I believe the name is the result of Australia being upside down... :-)
yes