The mp3 plays loop on MicroSD, the sinus sound is achieved in Daqarta Software. Also you may use normal 'getting signal' circuit. Will work aswell.

How to earn money from Paulos:

Making your own gen. One phase is enough for a start:

many modern amplifiers are too complicated for our purposes like digital pots, digital channel selecting. This all makes it more complicated if digital circuitry fails and they often does. That's why it is good to take amplifier kits, also the potentiometres aren't on the case, so it safer in use, another thing is you can use two mounting pots to set different voltages. Also most circuit applications let user to set the higher gain in right channel for ferrite by changing one or two resistor values. And it is well described in the datasheet. If I was You, I would take any old caps like 50V/3300uF to wound a noplis, a kit with i.e. TDA7294 with good heatsinks, transformer from a broken amplifier or dedicated in voltage, board for capacitors (they sell them), some fresh caps like 10 000uF/50V also noplis, wound a fat coil, and on a universal PCB i would make the circuits mentioned in the instruction (two 70mm universal PCB are enough for all the circuits). Buy the right triangle generator kit, buy automatic boards. Use a computer ATX socket from an old ATX PS for these, a computer cable is solid. Then I would use universal LED voltmeter and close all these in big universal Case, better steel, they are accessible on auctions and electronic store, maybe not cheap but worth a try. Including two or three blue sockets you would have a professional one phase power generator. in front A phase lamp indicator, a switch and voltmeter. Also you may try to make a 15V Carat Trax (40mmx 30mm with copper plates as first and last), use linear DC/AC inverter to power up the supply, so this would start without electric grid.

Then you may sell such generator for a good price. And start to manufacture. You will find many amatuers.

Everything depends on your effort, the skill is a minor thing.

Using heater my friend asked me:

I can NOT see any power SAVINGS by using CAPLOS.
How can that be?
Can You explain?

Answer:
so here is the answer, https://www.nrel.gov/docs/fy21osti/78472.pdf when you use on the whole installation the power is much mixed, there should be savings, but it depends on this triangle. those are three different loads or maybe even three types of electricity... and in your case its a pure active power, hard to dim, especially on S phase used in one phase installations. Try on R or T if you have such possibilities. Try on non RCD installation input/output. The resistor may i gave in schematic 5ohm/100W. May be better. I don't know. The capacitors capacitance count much too. What my friend was testing he found special average values for typical installation which i shown in my first caplos picture.

Third version of my handbook:

If you are using active load in caplos, better leave the resistors.

Block schematic of another version Paulos. This may run without fat coils... Only you need two different transformers (and volumes).