Hi,
I am debugging my ML332 with noise issue. I have the amplifier driven by a 1KHz 50mV sinusoidal. The final output to the speaker is fine. I probed around the voltage gain board using an oscilloscope with AC coupled, and see no signal at the 1st differential stage outputs, shown by the red dots on the picture. I suspected the input impedance of 10MOhm is low, loading the output. Even I changed the probe to 100x with 100MOhm input impedance, I still cannot see any 1KHz signal at the red dot locations at the low setting of 10mV/grid, while the 1KHz tone is clearly playing at the speakers. Anyone has an idea and experience on probing the ML differential outputs? I am puzzled.
Thanks,
cfy30
I am debugging my ML332 with noise issue. I have the amplifier driven by a 1KHz 50mV sinusoidal. The final output to the speaker is fine. I probed around the voltage gain board using an oscilloscope with AC coupled, and see no signal at the 1st differential stage outputs, shown by the red dots on the picture. I suspected the input impedance of 10MOhm is low, loading the output. Even I changed the probe to 100x with 100MOhm input impedance, I still cannot see any 1KHz signal at the red dot locations at the low setting of 10mV/grid, while the 1KHz tone is clearly playing at the speakers. Anyone has an idea and experience on probing the ML differential outputs? I am puzzled.
Thanks,
cfy30
