LM4780 heavy distortion at low levels

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a problem...

but perhaps not the only problem...the input offset voltage for the amp is spec'd as a maximum of 10 mV. With the gain of 33.35, that could make for worst case difference in output voltages of about +/- 3.33 Volts, or perhaps a 6.66 volt difference across 0.2 Ohms of resistance. That would be 30 Amps!
So maybe it's only 0.1 that amount, but that's still 3 A of current devoted to the parallel channels fighting each other.

for sure, remove the 0.1 Ohm resistors, as another poster suggested, and try the amp...or...measure the voltage across each 0.1 Ohm resistor...if it is anything more than 0.01 volts, you have a problem!
 

ra7

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So, if I understand correctly, the problem seems to be that one side has more gain than the other. I recall seeing close to 0.00V across the 0.1 ohm resistors. I'll check again and report back.

Thanks for the suggestions guys, really appreciate it!

Abraxalito, thanks for the tip on raising just one leg of the resistors. The pcb is tiny and it's very busy around the chip, but I'll give it a try.
 
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