I'm still not sure whether this is the right forum to ask this question. However, I must ask this somewhere.
I recently bought a cheap USB sound card , which seems to be using the chip CM108. It works well with my cheap desktop mic, service almost zero noise at 100%.
But the problem is, it fails to detect my Shure SV100 mic (which was the actual one that I bought this card for). The mic comes with an XLR to 1/4" cable, which I connected with a 1/4" to 1/8" converter pin in order to connect it with the sound card. This pin is functional while using with the built-in sound card (except that it produces a low output and a lot of noise).
In short, without the USB sound card, both mics work, but with noise. With the sound card, the cheap one works and Shure SV100 doesn't.
First I thought the problem would be of the pin which fails to convert the mic output to the correct channel. But when checked with Audacity in stereo recording mode, both mics produce (of course without the USB card) output in the same track. So that is not the problem. (Was it a foolish test?)
Now I think that the USB card ignores the mic due to its low output. Will that be the reason? What about impedance?