Here is assembled LM3886 x 3 (inverting) board. I think you may see similar/identical board before. Who is the original? Copycats are everywhere. The kit comes with a Solen like film cap. Most likely a fake one. The measured data is not too bad though. The three LM3886 are samples from NS. Original!
The kit provides 0.2R 5% instead of 1% for paralleling the three 3886. Gain setting is by 200k and 10 k 1% metal film. Three 50 k trim pot are provided for DC offset adjustment. I do not solder the three 0.2R first in order to see the gain of the three 3886s.
One of the 3886 DC offset can't be adjusted to 0.0 mV. It has ~25 mV. The other two can be turned to 0.0 mV. This may cause a problem among them. Let see.