This circuit is from an old Japanese publication of 1962. The circuit uses two batteries, one for the filaments of the tubes and the other one of high voltage for the plate circuits.
We found this circuit for vocal effects in the September 1990 issue of Radio Electronics magazine. The...
The original design of this circuit is from a 1978 publication. The circuit can be implemented with a...
We find this circuit in a 1980s documentation. The integrated circuit used is unusual today. The...