This Japanese radio is from the 60s, presenting excellent sensitivity and an output power of 100mW with 6 V power from ordinary batteries. The circuit is of the superheterodyne type.
Found in Motorola's 1968 documentation, this control appears elsewhere in this section. The bridge...
The circuit below is suggested by National Semiconductor in technical documentation on the LM3909....
This preamplifier for phonographic capsules using FET was found in 90s American documentation....