Hybrid 12V tube super hetrodyne tube radio

I look at the Car tube radio , they using the tube call “Space charge”. Normally the tube call “space charge” is the g1 apply positive grid. but most of the tube look like ordinary tube but they can work well at low anode voltage.

I have alot 6J1 (6AK5) and 6J2(6AS6) on hand and the tube heater only require 175mA current. The battery tube radio cant see the filament during operation, but 6J1 and 6J2 can glow red on cathode it look pretty cool. So i design 6J2 work as mixer, and 6J1 as IF amplifier, the detector by 1N60 and go into LM386 audio amplifier.

At first experiment i was try to Power whole circuit with 6V , the 6J2 no work well can’t oscillate, so later i found 6A2 (6BE6) tube have same pin out so i plug in it can oscillate at 6V.. and the sensitivity is poor , i was using Signal generator modulate with music and test it as video below:

After many years i think if i increase the voltage to 12V by series the 2 heater and i check LM386 able to work at 12V too, so i give a tried and found 6J2 can oscillate well at 12V. So i quickly find a MW antenna rod and to test it.. it work well . The volume have to turn to maximum only i can heard a good volume, so i decide to make LM386 have 200 gain instead of 20, So after increase the gain i make another video again in video 2. In video i purposely adjust the Local oscillator coil to show the 6J2 mixer is actually working.

The schematic as above.. I don’t remember the IFT data , the IFT coil is i rewind by myself is not MW oscillator coil. The oscillator also rewind by myself.