His 12V battery is in the wrong location and the circuit has no input signal so it has no output signal. Even the DC output voltage is wrong.
Also R5 is shorted.
oic, thank .... i want to ask , can i try the master circuit and slave circuit respectively by meansure the output voltage signal from speaker, without connecting both togather?
When you adjust the trimpots to null the local signal then there will be nearly nothing coming from your speaker when you speak into your microphone. The sound comes out of the distant speaker. That is how it avoids acoustical feedback howling where the mic hears the speaker and causes the sound to go around and around making feedback howling.
i was try the master circuit , measuring those part with Gnd, and the voltage i measured as list, i dunno why the base of transistor input so high , and the mike seem not worked....
and when i measure output 5 & 8 from the TDA7052a, the circuit became short circuit.... zero voltage measured....
The DC voltage at the base should be +6.0V, not +6.8V.
The voltage at the emitter should be about +5.3V, not +9.5V.
The voltage at the collector should be about +10.3V, not +6.0V.
Ground should be 0V, not +1.14V.
R7 should be 0V, not +0.6V.
Both outputs of the TDA7052 should be the same, probably +6.0V, not +1.0V and +10.6V.
The original circuit and Boncuk's circuit show the polarity of both C4 capacitors backwards.
I showed the original circuit's TDA7052 datasheet that has its pin 2 input grounded with a resistor. I also showed your circuit's TDA7052A with its pin 2 input grounded through the volume control but the datasheet shows a coupling capacitor maybe because it has DC on it. Maybe that is why the DC at the output of the TDA7052A is wrong.
The datasheet for the TDA7052A does not have enough details and not enough spec's to show why its circuit uses an input coupling capacitor but the TDA7052 does not show an input coupling capacitor.
Maybe the input of the TDA7052A has a bias voltage that must be kept so it needs an input coupling capacitor. Then when the input is wrongly connected to ground through a resistor it might cause the outputs to have severe offset voltages. I don't use the lousy old TDA7052A because its datasheet is missing so many details. Instead I would use a TDA2822M amplifier in this circuit.
i will try the TDA7052 , and maybe TDA2822M also .... izzit i just need to change the IC part as shown in http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXqwxzy.pdf (page7, figure 17) ?? just using the pin1,2,4,7,8 or pin 2,3,4,5,6 and connecting capacitor with pin 8 or 5 to ground , and also the output part?
I think the TDA7052A will work properly if you add the 0.47uF input capacitor that is shown on its datasheet. Don't forget to correct the polarity of both C4 capacitors.
You do not use the stereo amplifier in figure 17 of the TDA2822M datasheet. You use the mono bridged amplifier circuit in figure 2 and its pcb design in figure 4.