The trip to DV Brum was useful. The problem is unbalanced cables. In theory, they should be OK. However, we tried a Saffire 6 with balanced cables and hey presto, no noise but inferior sound quality to the PCI 2496. We also tried an RME Babyface. Bad idea. Far superior sound quality but at a horrible price. So, the question is what is the best way forward. I really want to stick with the PCI option if possible. The Saffire 6 was a bit fuzzy sounding to me. I had thought maybe an M-Audio 192 with balanced outputs might be the answer but I read that someone with the same issue tried this but it failed to solve the problem. It seems the only choices are the ground loop box or the pseudo balanced cable after all. I am just a bit worried about the loss in sound quality. Sorry to drag this one out but does anyone have any further thoughts?
Sorry to but in late on this one, but you from the info given in this post you can't say that 'it's cables' when you exchange a PCI interface for a Firewire or USB interface and the problem goes unless I'm missing what you're doing? From the info given, all that can be said is that your computer seems to like USB or Firewire better than PCI but maybe that can be fixed..... Could still be a digital noise problem getting through. Not saying it is, just questioning this little bit of the fault finding or at least my understanding of it from what you've written. Apologies if I have the wrong end of the stick
I see that you've disabled 'EIST etc' in the BIOS. Have you done the C1e thing? If not, you may find it useful to read my tale of woe with noise on an ASUS board here
Again, if you've done all this then my apologies - I'll shuffle on by