Organ of lights & audio amplifier 1983

When I was 16 this was a 'must have' for a party.
The tape recorder, an amplifier, the organ of lights and a ball with mirror squares.
This was the simplest circuit diagram for an organ:

at the audio input it has a transformer for wire broadcasting.
In the high school we assembled wire broadcasting speakers. These had 100 Ohm coil potentiometers, transformers and loudspeakers.

The transformer was good for galvanic separation.
I also put a neon bulb to identify the phase, first time w/o serial resistor. When I checked it I get an electric shock, of course. I added the serial resistor...

As audio amplifier I used the kit sold at Bucharest 'Silicon valley' - Academiei street

This circuit was OK and I remember that Horia Tanase, now professor at the University of Athens, Georgia, asked me to assemble 4 amplifiers in a briefcase in order to be easy to transport the amplifier unit to the parties where he was invited...
We tested the sound in my father's garage with electronic music.