someone made some good pictures of the boards of c01u, (and some explanation)
http://jumperone.com/2011/10/samson-c01u-teardown/
is this enough or a diagram would help further? i can also take more pictures if needed
We can't really have any useful discussions about the circuit design or operation without looking at the circuit diagram.
Randomly poking around blink is not only a waste of time, but very likely to be fatal to the circuit if you poke the wrong place.
the preamp is built into the adc chip (24+24db programmable gain amplifier)
That severely limits what you can do to quiet the audio path. This kind of "all in one" microphone was not designed for high performance. It was designed for convenient operation.
all the noise is coming from the small board as i bypassed the megohm resistor with a small cap and the noise was gone (but also the signal)
Which is exactly why it is such a large value resistor, to avoid draining off the very miniscule audio signal.
Putting almost ANY value capacitor in that spot is guaranteed to short out ALL the audio signal and leave you with nothing.
what i am not sure yet is if the noise source is the 50megohm resistor or the capsule itself,
It is probably a safe differential test to simply disconnect the capsule and see how the circuit behaves by itself.
Then you will hear only the circuit noise, and nothing from the mic capsule.
VERY IMPORTANT NOTE!!!: That "solder blob" where the capsule connects is the VERY MOST SENSITIVE part of the whole circuit.
The reason it is floating like that is because the most minuscule, invisible substance could cause major problems and quite possibly render the circuit non-functional.
I can't stress how important it is to treat that node with extraordinary care and make sure it is scrupulously clean.
Even left over solder rosin residue that is completely invisible under a microscope can severely damage the audio signal.
We use special no-residue solvents and methods to clean that extremely high impedance node to eliminate any trace of leakage.
Messing with that node at all is a very bad idea and to be avoided if at all possible.