Why is the 220uF cap at the output included twice (C7 and C8)? Wouldn't it be easier to use one cap and switching only R13 or bypass? One could either put the single cap on the other side of the switch, between pin 5 and the switch or right in front of CON3.
Hi Bas, we originally included 2 caps c7 and c8 in case that the user wants to have a different frequency response for headphones and for a speaker.
This cap affects to the amount of bass going to the output. If you use headphnes, using a big cap (220uf) will give plenty of bass, but if you use a small speaker sometimes too much bass can make the speaker to fart.
In that case you can use a smaller cap for the speaker output (100uf or even 47uf).
But going again to your original question, if you want to have the same freq response for headphones and a speaker, you can use a single cap and just bypaas the resistor.
