Magnus Danielson wrote: > Dave, Bruce, > > >> Need a few more circuit details. >> The crystal current wont be very high unless their are other components >> connected to G1. >> > > As expected, BAMA can assist: > http://bama.edebris.com/manuals/tek/184/ > > I am thinking about undamped overtones/other modes of the crystal and > similar. > > Cheers, > Magnus > The crystal oscillator is in effect a miller oscillator using the screen grid as the oscillator anode/plate see: http://www.ieee-uffc.org/freqcontrol/tutorials/s6310508.pdf
The oscillator plate/anode (screen grid is grounded) in this circuit. The tube plate/anode forms a well isolated auxiliary output tuned to the 5th harmonic of the crystal. If the tube emission has dropped the gm may have fallen rather too close to the critical value required for oscillation making the circuit sensitive to loading at the grid. Both the trimmer and the cathode tank slug affect the frequency. Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
