Hi sir Vedmitra, yes, but no good news yet. What i found out is the first units of this amplifier i used bd911 and bd912 and now i'm using tip41 and tip42, and also, i used the bc327 instead of bc556, using only 2 diodes for thermal compensation is more stable and generate less heat, and, to top it all, the latest Tips 142 and 147 has changed, i don't know why but they tend to be more unstable than the old ones and the quality of the output is horrible... I will retest it on the Multisim and change some values. i think i'll change the diodes with a vbe multiplier, and some resistors. i still have 80 boards of this amplifier.
Here is the pic of the one i was using on the first units:
And the ones that is creating all that troubles:
Sorry for the late answer, i was busy with my final tests of the semester and the final project at the university. but now i'm on vacation, and i have some more time ... i want to make this amplifier stable and with low distortion like the first units i build.
I'll post some tests in multisim with some modification and the pics of the board i'm using.
Best Regards
Flavio Lira