This 6W amplifier with 4 tubes was indicated in an American documentation from 1947 to operate with recorders. The circuit uses a source with a transformer.
We found this version of the siren that makes the American police siren sound in a 1980...
This microphone circuit was found in a collection of American 80's layouts, using operational...
The integrated circuit used in this filter is like to a double 741 and must be powered by a...