Thanx Marc JX8P.
Actually I can use an interface with a 2 mic pre-amp input but I will check out the Fast Track Pro Ultra.
How is the latency with USB2? I知 going to assume that you use it live that it is less the 20 ms. I have read that USB2 interfaces are slower than PCI(e) cards but I don稚 know for sure.
Thanx again.
The Ultra is basically a bigger Fast Track Pro, so if you want just two mic inputs (aside from the S/PDIF) then you can go for that even cheaper option. I'm using the Fast Track Pro with my Macbook, and according to the control panel it gives me about 9-10 ms latency on 48 kHz. It's also bus-powered which is really nice.
USB2.0 is plenty fast enough; my new RME Fireface UC interface is USB2.0 and it manages 18 channels in and 18 out under 44.1/48 kHz. The issue is always the quality of the drivers and sometimes other processes can screw up the communication with your audio interface. For example, for my old laptop I had to deactivate the network interface as that produced occasional spikes in the CPU load which resulted in pops and clicks in the audio.