This power source was found in a 1969’ Electronics World. The version is too sophisticated by the current it supplies and can be implemented with modern transistors.
This basic tone control circuit employs a Philips NE5538 operational amplifier, but can be adapted to work...
The integrated circuit of this 80's project is not common today. This is the HA2530 which must be...
This circuit was found in a British documentation from 1969. It can be implemented with modern...