This circuit from the 80's makes use of two transconductance operationals of the time. Modern equivalents can be used. The circuit does not need to be powered by a symmetrical source.
This mechanical reverberator circuit for guitar was found in the February 1970 issue of Radio...
Found in an old English publication this circuit uses a dual gate MOSFET. Coils not specified....
This is the receiver for the previous circuit transmitter. Similarly, no information about the...