Hi guys, I've got this issue. I've got a Saffire pro 24 DSP and a Condenser MIC, using a desktop PC (Windows XP). A really cheap computer (I've got a blasting new one but couldn't make saffire pro work with W7 Ultimate 64bit, but thats an other topic).
Important Part: When singing through the MIC or playing an instrument without recording on my DAW (sonar) everything goes fine at any level on input and output for my headphones (I know I get the normal 'ambience noise' sound when cranking it up to 10). But when I have to monitor through the DAW it starts with 10 seconds of normal sound and then starts this horrible noise. So it records with that noise.
Not sure what can it be, I have a pci to firewire card with the correct TI chipset.
I've recorded something so you can hear exactly how it goes: Saffire Pro 24 DSP DAW noise by marcosgriselli on SoundCloud - Create, record and share your sounds for free
I remember you, I have no trouble when monitoring through MixControl or when playing an audio file. Is only when monitoring/recording in DAW