I have been recording with two M-Audio Nova microphones and an M-Audio MobeilPre USB for the last year using Logic 7.0. on my 1.6ghz powermac G5. Recently a major problem has arisen. During recording in both Logic and Garageband, there is a very loud intermittent beeping sound. Sometimes it is only once a minute, sometimes it is every few seconds. I know that there is no problem with the microphones or the cables because I tested recording without the microphones attached (recording straight from the preamp) and the problem was still there. I checked the M-Audio website but they have not updated the drivers for the MobilePre USB. To test whether the problem was with the preamp, I simply connected my speakers directly to the preamp and used it as my main audio output (driver) and connected the mics. The preamp has an automatic mic-preview turned on when Phantom Power is activated: the preamp outputs the sound from the mics directly to the speakers without the need of a software app. When I did this I found that the mics worked fine and there was no beeping noise (it's kind of like a very loud high frequency click/beep when it happens). I went back into Logic and Garageband and they still recorded the click (it isn't a speaker problem because it is really in the recording and I can see it as a very short small peak). This leads me to believe that there is something wrong with either the computer or the software. Since the problem occurred in both garageband and logic I can assume it is not a problem with either program. This leads me to believe that this is resulting from some kind of problem with the drivers in OS 10.4.1. That or there is a possibility that the problem is still with the output on the preamp to the computer, but I don't know why this would be. Does anyone have any similar experiences or can they see what is causing this problem. It has become a major annoyance. Any help is welcome, thanks.