Quote:
Originally Posted by Chris K
I fed an audio signal through the grid of the 6AT6 and the sound system from there forward works...speaker, AO transformer and tube and the volume control. I fed a 21.5 MHz RF signal through the plate for both pin 2 and 7 of the 6AL5 and didn't get a signal through the speaker with either. Am I doing something wrong here? I tried about 4 different 6AL5s but nothing changed. I'm sure I'm doing something stupid!  |
The 6AL5 Sound Discriminator(detector) plate circuits are not tuned to the 21.25 mhz sound IF. To hear sound you would need to inject your 21.25 mhz carrier with FM audio modulation into the grid of the 1st or 2nd audio IF amplifiers.