Got some screetching noise with pci 324 + 1224.

[AthenA714]

Where does it come from ? That's my main concern. If it comes from the 324, I'll probably gonna change it for a few bucks, but if its the 1224, that's gonna cost me a lot more !

I unfortunately have no others motu hardware than my pci 324 and my 1224, and I don't know anybody that own some. Therefore I can't test these 2 elements separatly. Can you guys help me find out where the problem is ?

Here is a description of the problem : the noise is like those scratch you hear in a bad encoded mp3 file, it's not like a buzz due to a cracked solder, it's more "numeric". It comes on the left channel, on the headphones, main out or any analog outputs. It appears to come at a certain frequency, the more "sound" there is the higher the frequency (perhaps one cycling scratch per track). A fact that is important (I think) : the level of the "scratch" does NOT depends on the input level. If the audio source has a very low level, the scratch can be clearly heard, but if I put an audio source with a high level, the scratch stays at the same level and will not be heard. I tried differents cables, differents speakers, and I tried the 3 ports on the pci 324, same problem everywhere.
I *think* (hope actually) this noise comes from the pci 324, cause I don't see anything in the 1224 that could insert a numeric scratch in the left channel. The fact that it appears on all outputs with any source (input or audio reading from the pc) makes me think that it has nothing to see with the ADC/DAC.

So can you guys help me ? If you have any similar experiences, any hints or anything that I should check, just tell me !

PS : hello everybody for my first thread !

PPS : I forgot to mention some information about my computer : I'm running windows XP on an athlon XP 3000+ with 1,5 GB of Ram. I have another sound card installed (audigy 2, for watching movies & such) and I tried to reinstall the drivers completely. I also tried several PCI ports for the 324.