This transmitter for the 3.5 and 7 MHz ham radio was found in a 1950s Japan publication. No information was given on the coils and the power supply.
This amplifier has a few Watt output, using old transistors. The speaker is 45 ohms, but with...
This circuit was found in a 1994 documentation. The transistors can be BC558 and BC548 and the...
This Baxandall tone control circuit is based on the JFET integrated circuit at the CA3140 input. The...