Ah trodas. You are *king* of power supply management capacitor mods :-)
I'm surprised you are asking these questions, esp. here. I would imagine very few TPU members are electrical engineers, but you never know. I'll watch this thread closely.
Capacitors are used for purposes OTHER than being a "reservoir" to hold charge in a "DC circuit". Audio amp circuits are an interesting opposite, since here capacitors are being used in an AC circuit.
I'm an amateur so here is my understanding of what is going on, but it is very possible I am not 100% correct:
- C1/C2: a snubber (protection), you never know what residual charges might exist on the input jacks when you connect.
- C3/C4: to decouple the input from the opamps or you will blow them.
- OpAmp 4558D has been set up as an inverting circuit. http://webpages.ursinus.edu/lriley/r...its/node5.html
- C9/C10 are obvious. This is an audio circuit. The output should be AC. If its not, or it is biased, you dont want to amplify that bias or fixed DC in the output stage or you will saturate or blow the second stage.
- C13/C14 are not so obvious on your zoom, but obvious if you go to the full schema. You need to decouple from the MIXED, SUBWOOFER take-out from the MULTIPLE inputs. And yes, this gives a second reason for C9/C10... you dont want to send a bias to the subwoofer circuit.