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Folks,

I have been struggling with this project since last April. And I received good advice and suggestions back then.

But it got to the point where I felt that I no longer believed that the LM386 was the right IC for this project. (It was pointed out to me that it was ancient.)

So I've redesigned things a bit and will be using two MC33171N ICs.

The schematic was redone but was largely unchanged. That is, I substituted the new ICs and added, changed or removed connections accordingly.

So, for example, there's no longer the bias cap from the LM386 pin 7. And there's no longer a pin 1/8 gain adjustment.

But as the overall design is from an LM386-based schematic that I found on the net (and failed to store the link) certain components are still in place.

For example, the product info on the MC33171N shows me a freq. vs. impedance graph which suggests to me that the IC's output, unlike the LM386, is not 8 ohms.

Can anyone tell me what the likely impedance would be based on my circuit?

Also, there are a few holdovers as I mentioned. What purposes are served by the 220μF and 470nF caps on the output stage? For that matter I never understood the purpose of the two 470nF caps leading into the "Summing" 2-gang balance pot.

So I welcome your answers and suggestions.

Thank you,

Roy