Passive mixers, I don't undertand why the resistor/capacitor Answered
Hi, when I was young, our teacher show us a passive mixer, each input had only one green capacitor in series for each input, it was not electrolytic but ceramic or polyester, it sounded so good for just being there 1 simple component per channel. Now taking a look at google, can see that the most passive mixers, uses resistors to isolate sources, with values since 10k to even 100K. Other schematics shows a resistor and capacitor in series (see image below) what does that capacitor? and why some schematics only has a simple resistor? is it easy to calculate its ohm value?.
Is it better using this configuration supposing that the source is weak (coming from cellphone 3.5 mini jack or RCA) and this mixer targets the signals to a pre amp? So I need to from weak sources like iphone, dvd, any RCA output, etc... anybody know whats the best to use in this case? Thanks so much. Should I put a resistor as minimum as possible? I undertstand that a resistor there, in the input, will reduce the volume input, and I dont want to do that, so can I simple connect everything direct? or the resistor isolates the inputs, otherwise it will sound ugly? I am very confused, why the resistor? why I have seen resistors from some ohms to 2km and even a lot more, 50k, 100k. I want to mix two weak sources, as a signal coming from a walkman and cd player, or cell phone, etc, so whats the law for not reduce signal intensity and mix everything well? all channels will come in into a pre amp IC.