It might be that the phantom power in your 122 has a problem. The way you described the noise ramping-up after you plugged the mic in could point to this. Or, it could be a problem with the mic, although I'm leaning towards the 122 as the culprit.

The 122 is a pretty cheap mic pre audio i/o, and more than just a few of those models have had problems - I personally know of three people who have had them and had to return them for exchange or to get something better.

If you do find out it's the 122, I suggest that you may want to look into a Focusrite 2i2 or 2i6 instead... roughly the same price, but far better in terms of preamp quality and overall build.

Tascam has just never really managed to get it together with their preamps - cheap components, lots of service problems, and very low gain.

Have you tried the mic on another preamp, just to rule out that it's not the mic?

That is a fantastic answer. :) No, I haven't tried another preamp. I'll get my hands on one. Thank ya!

I wanna add some more information to this. I used the same equipment with a different computer, and there's no noise at all. Which, of course, seems to suggest that it was the computer that I was using. Might that be some sort of soundcard issue or whatever? I definitely don't know much about the tangible parts of a computer that are involved in this stuff. :)

Just a guess but I'm wondering if there is an audio output from another device or however your card is interfacing with the other audio outs on that computer that is not muting. In other words, besides the [[url=http://[/URL]="http://www.www.tasc…"]Tascam[/]="http://www.www.tasc…"]Tascam[/] US-122L interface, is there an open channel in your audio path cranked or not bypassed. A computer wouldn't do this sort of thing but the audio configuration could. It sounds like the other computer is set-up correctly. I'd look at all the settings and see whats different between the two so you walk away from this a little wiser. Please share what you find as well?.

Just an FYI, I personally have found, some USB ports can add noise all on their own. Example, move a mouse around, hear noise in speakers in conjunction.

Makzimia, post: 425436, member: 48344 wrote: Just an FYI, I personally have found, some USB ports can add noise all on their own. Example, move a mouse around, hear noise in speakers in conjunction.

Good point. You mean the zipper effect?
That can be a CPU starvation? Too many things going at one time. Again, a settings or need for optimization. Could be the the OP is using a computer loaded with more than the audio and interfacing can handle.

Combined cheap USB port chipset can cause it.

One thought comes to mind, grounding. The fact is that computers use switch mode power supplies and the grounding schemes rely on many factors. One factor I was thinking of is the face plate on the computer I/O connects. There are usually little tabs that connect to various places on the face plate/chassis and the actual components from the motherboard. So if your using USB or something there could be a grounding issue there on that one computer. If the power supply was bad then I would suspect other problems and noise/failures.

I feel as if I'm at the airport with all this stuff flying over my head, haha. But I definitely appreciate the help. :) Fortunately, I got my hands on another computer that isn't giving me problems.

DrGonz, post: 425446, member: 32376 wrote: One thought comes to mind, grounding. The fact is that computers use switch mode power supplies and the grounding schemes rely on many factors. One factor I was thinking of is the face plate on the computer I/O connects. There are usually little tabs that connect to various places on the face plate/chassis and the actual components from the motherboard. So if your using USB or something there could be a grounding issue there on that one computer. If the power supply was bad then I would suspect other problems and noise/failures.

I'm no electronics expert, which is why I'm presenting this as a question, instead of stating it as an opinion - doesn't a ground issue usually present itself as more of a hum than a hiss?

We need to hear a sample of the problem posted on Soundcloud. Until we can hear that, everything is just speculation.