Found in old American documentation, this circuit makes use of operational amplifiers from the 70s that are not common today.
This vibrato circuit was found in Motorola's 1966 documentation. The circuit uses transistors of the...
Found in a magazine 73 for radio amateurs, in a 90's edition, this circuit uses a general-purpose FET...
This circuit is from an old Popular Electronics, but it can be easily implemented nowadays, even...