Hi! There is no way to measure such a small value. Made based on your measurements and photos. Also tried on the wires to remove it from the board.
Offff, look only for first decimal after the comma.
For example: 44.9543789 must look only for 44,9. If you measure 50 it os ok.
Regards,
Tibi
For example: 44.9543789 must look only for 44,9. If you measure 50 it os ok.
Regards,
Tibi
So I can not run the board with the operational amplifier, and accordingly make measurements. The op-amp was bought by Arrow and it worked on the mini version(OPA1641)
The ground star should be at input connector. Better use groud plane.
Move the coil from input and cascode.
Regards,
Tibi
You can NOT run the amplifier without opamp.
If you are able to do so, there must be a faulty component. Look at C1,C2, C7.
Regards,
Tibi
Have you not seen the video? It is clear that without Op-Amp the amplifier will not sound. But the supply voltages without op-amps are normal, there is no short circuit. On the common buses +/-35V, on the op-amp supply +/-15V, LEDs emit light. If you install the op-amp, the fuses burn out.
Of course we believe you. We only describe the normal behavior of the amp. Without an op-amp, the base of Q7 is in the air and causes an oscillation which saturates the output transistors. At 35v DC, R10 will take longer to burn out. 5-8 seconds for R10 is when powering the board at 50vDC. Just because the amp doesn't burn out or do not break fuses without an opamp doesn't mean it works. Leave it on longer without opamp and you will surely see that R10 heats up.
Regards,
Stef.
Regards,
Stef.
I think the board is unfortunate. The roads around the ОА are too long. The coil is close to the small transistors .
I have not got a chance yet to remove the FQP mosfets and replace with 610/9610. Will do that tomorrow.
I don’t have a good feeling Aboutaleb the q17 giving so much trouble getting functioning after putting so much serious effort in assembling carefully. And using the precribed quality parts! Hope you will succeed in getting the machine running and sounding great soon.
I am waiting for my parts, including the original latest Tibi pcb......
Yes thanks @ed linssen I am also intrigued that even after using all prescribed parts from known sources its giving issues. In fact I am building an amp other than class A after a long time now 🙂
Hope I can make it to sing next week.
Hope I can make it to sing next week.
Hi Julien!
Is it Tibi's original or Stephan's miniboard you are talking about? Just curious.
Quick update even after changing to IRF610/9610 the board behaves the same. Bulb is not getting switched off or low brightness and its consuming around 1.7A using a 0.1R resistor on the positive supply side with the bulb tester itself. I have given up now on these version of boards and maybe try the mini version which seems to work successfully for most of the people. I will try and salvage most of the expensive parts like caps and transistors. But thats for another build few months down the line.
Thanks
Thanks