President JFK -Microphone amplification

[rooth]

Hello !
I have a President JFK radio with original dynamic microphone, which I am not satisfied with the modulation. Even with the maximum gain it does not sound too great. What can I do in this case?

[ch25]

Replace dynamic capsule with electret and add 1 resistor and one capacitor inside radio.
This thread: viewtopic.php?t=55896&p=510107
Chris

[rooth]

@ ch25 :
Thanks for the info!
You have a beer from me!

I try ,and come back with an update .

[4a0026aleks]

the best way to remake the microphone is to add an amplifier to the tangent on a single transistor 2sc945 and make power over the wire

[rooth]

+ Pozitive how do I send it via cable to the microphone? I don't have a separate cable for this ...

[ch25]

Yes, via modulation cable. That's why resistor and capacitor are inside radio. I usually unsolder modulation cable from socket, put capacitor in series, that resistor and +8V available from many places inside radio.
Chris

[rooth]

I can't understand that. You can attach or diagram ? Please ...

[ch25]

Put electret capsule to the microphone. Close it, you're done here.
Open radio, find a cable connected to pin 2 of mic socket. Make a change as marked pink on image I attached.

Untitled-1.jpg

[rooth]

I already burned something. I touched something with the tester on the microphone jack and I did not sound and it does not seem to sound when I press PTT.
A sound is heard in the dynamic microphone when you press PTT

I reached pin 6 (13.2 V) at pin 1 - modulation

[rooth]

I managed to start the radio again. I fixed the problem ... I found an interrupted minus route.
I try again to adapt the microphone with the electret

[14CS06]

Hello

My post is gone
Is that normal

@+
Claude

[cb4ever104]

I try again to adapt the microphone with the electret

To get the best result make sure you pad around the electret using any suitable material . I cut some foam sheet to size and used that , making a small hole in the middle for the element .

S.