This receiver was found in a Popular Electronics from the 90's. Its different configuration shows a tuning circuit after the tube that works as an aperiodic amplifier. Observe supply voltages.
With the components indicated, the circuit oscillates at 20 MHz. The coils and capacitors can be...
We found this preamplifier circuit with high input resistance, on the order of 30 M ohms, in an...
This symmetrical 1.2 to 35 V source was found in a 1994 documentation. The integrated circuits are...