Please see spec below. When I hook everything up to the Macbook, all is good. When I hook everything up to the iMac, I get a high frequency but quite siren noise coming from my speakers? This is with iMac turned off, but with the power lead plugged in and sound card connected via FW. A process of elimination means it has to be something to do with the circuitry of the iMac. I have installed the latest driver for the FW Solo (1.10.3) on the MBPro, but this version will not install on the iMac so I am still using 1.10.2, but I know its not a driver issue as 1.10.2 was fine on the MBPro. The thought of having to take all this kit into the Apple store to demonstrate the problem, well, I don't even want to go there Any others experienced the same?