We found this Vox in a 1969 Motorola documentation. Transistors support modern equivalents and the SCR can be a TIC106. The reset is done by a push button.
This is a high efficiency version with the MC723 which is the Motorola version for this well-known...
This circuit was found in the March 1997 Electronics Now magazine. It uses a common analog...
This circuit is from an 80's documentation. It makes use of two SCRs with current capacity...