This circuit with 1% regulation aims at replacing mercury cells. We found it in a 1967 documentation. Transistors can be replaced with modern equivalents.
This circuit can be interleaved between guitars and guitars to give the fuzz distortion effect. The...
This 1969 Philips documentation circuit makes it possible to control an engine through the sound...
This circuit, suitable for tube equipment, was found in an old documentation. It uses a high...