I have a Focusrite solo hooked up to my guitar. I managed to get sound from it in my headphones. However It sounds like some weird reverb. The sound get a bit louder and then goes completely away and then louder and then completely away, ... I have now idea where this behavior comes from.
I am using Jack and guitarix. The reverb is not an effect! If I am not providing enough information, please ask. Also note pulseaudio is killed and I get no sound other then my guitar.