*Another* crackling sound issue with Mbox 2 Pro

[Goanna]

I've just purchased the Mbox 2 Pro and teaching myself ProTools (ha). Have been connecting it to a desktop via FireWire PCI card and 6 pin cable. Mostly no problems. Sound quality good. Both Mbox and software working fine.

Have now tried to connect to a laptop that has only a 4 pin firewire connection. Have connected power supply to Mbox and used a 6 -> 4 pin cable. PT connects to Mbox OK. But when I record or play audio from Mbox there is a crackling sound in output 1/2 and 3/4.

Any ideas what might be causing this? Could it be the cable? Interrupts?

Thanks in advance.

[Goanna]

After a bit more research and noting lack of responses, I think this issue is specific to me.

If I bounce the recorded audio to disk and play it through any old software it sounds fine - no distortion, nothing. So the input has worked fine. Given the distortion only happens when playing back from laptop on Mbox headphone or analogue outputs - and the distortion doesn't happen when playing back from the desktop - it leads me to the conclusion that there is a) nothing wrong with the m box and b) something wrong with the output from the laptop to the mbox. That means either the cable or the port itself.

[Goanna]

It was the cable! What are the chances of that?