I have just received my FX100 one week ago, which I decided to buy as soon as USB recording (and Android support) were added.
Even though I have nothing against using Windows for recording & editing, I am always looking at alternatives like Ardour 3 in Linux...
and I have to THANK a lot Line 6 for having made the Amplifi series USB Audio v2 Class Compliant (a side effect of Mac OSX support) as now we can try to use it in Linux too.
I have tried different version of Linux but some older releases like Ubuntu 12.04 seem to have issues. However, I am happy to report that I have my FX100 working perfectly with my XUbuntu 14.04 64bit, kernel version 3.13.0-40-generic #69-Ubuntu SMP and ALSA drivers 1.0.25+dfsg- all. It is not a fresh install and it was actually upgraded from XUbuntu 12.04 but I have not changed any settings to make it work. I will try to install a fresh version of the OS but so far so good.
It also worked on the latest Linux Mint from a liveDVD but I had issues (device detected and driver loaded but error with the sample clock settings) with UbuntuStudio ...
Ã‰dit: after a second trial, it actually works in UbuntuStudio 14.04 without any tweaks!
Anyway, I just want to tell all Linux users that there is a good probability to make it work in recent Linux releases and it is definitely worth trying to identify which Linux variants / kernels version actually support the Amplifi series!
And also, as a side note, the tones of the FX100 and sound quality through my little Blackstar HT1-R is just great, much much better than what I could get with my old Pod XT. And it really feals natural sounding through a tube amp. I have tried two setups:
a) either pluging AMP OUT of the FX100 to the HT1 guitar input and setting the clean channel with gain at about 2-3 and volume at 10, ISF on the right for "US" settings (= more bass and treble). The FX100 volume is set close to the max to match my guitar volume. This config allows me to bypass the FX100 amp sim section and use it as an effect processor if I want to keep the Blackstar tube preamp tones: in this case, I can raise the gain of the clean channel to go to a crunch tone or switch to distorted channel. Some of the FX100 amp models also work decently using this config, but as it is not 100% flat response, you will need to tweak a bit the EQ and be carefull not to drive the tube amp to hard to avoid distortion on the amp side.
B) or taking the stereo Line Out and pluging it to the AUX input (direct connection to power amp) but I have to set the volume of the FX100 to a very low value, about 2-3 max to keep a reasonable practice volume. This gives me the best tone quality for all type of tones, from clean to heavy distortion. The guitar sound feels much more natural through a tube amp and guitar speaker actually, it is warmer and rounder than the headphones out. Quite amazing sound quality and versatility for an affordable tiny 1W tube amp setup, all that thanks to the FX100!