This is the circuit of the commercial Japanese megaphone of the 60s model DM-218. The circuit uses a compression speaker (horn) and is powered by 4 large batteries. The output power is 2 W.
This circuit uses currently uncommon components, including the 10.7 MHz (FI) filter. This circuit was...
This circuit is from a 1965 Electronic Design. The transistors may be general purpose and the...
This circuit is from a 1980's documentation for telecommunications. The circuit is used in SSB and...