I just aquired a Fireface 800, with intention of using it with Pro Tools 9. Everything starts up fine, and then I proceed to test the inputs and outputs of the FF800, to make sure everything works a-ok. So I create an instrument track and load up a signal generator, then I route it through the different i/os and make sure all the levels are the same. Anyway, in doing this, I came across what I think is either a bug with the ff800, pt9, or the combination of the two. I figured this'd be as good a place to ask as any. What happened was this;

When I changed the output from for example output 5 to output 6, I noticed that sometimes the previous channel would not be muted, as expected. Even after removing the signal generator, the previous output channel was still emitting some audio. It doesn't show up in the pro tools mix view, but it reads in the ff800 mix software, and it is also audible on the physical output. I found it strange that this channel was outputting audio without anything being routed to it. I recorded some of the audio and it turned out the be a short sample of the sine I had generated, played back at fixed intervals, with some silence in between. I wanted to see if it was indeed a snippet of my source signal, so I tried generation a saw-wave intead, and yes - then the "ghost signal" would be short slices of saw wave. Weird, no? I tried switching around the outputs of an audio track, in playback, but couldn't replicate it there (thankfully).

I have the latest firmware and drivers for the ff800, and I downloaded the latest PT9 version, but no sigar. I'm on win7 64bit if that is useful.

Any idea as to what this is? Sorry if this has been brought up before. I tried searching but didn't find anything that matched.