glebb

In theory at least it's possible, if you have the right appliances: I build this kind of box for myself. It's connected to Stomp with TRS cable. It also has TS input for EXP pedal. On the face it has two buttons and switch. If the switch is up, both buttons work, and can be set in stomp to FS4 and FS5 for example, but Expression pedal is disabled. If the switch is down, it disables the button on the right (FS5) and enables Expression pedal, and you still have FS4 available. Of course changing the "configuration" with the switch also requires you to change some settings in the Stomp itself, but all in all it works quite ok.

What expression pedal do you use? I think that's a great advice, and I'm probably gonna go for it, just need to find a suitable pedal.

I finally made it work for me. As the Stomp doesn't seem to have the possibility to select USB out in dual chain scenario I needed some other way to route DRY signal from Stomp to RS (again, without using RS cable). I found a software called LoopBack (https://rogueamoeba.com/loopback/) and with that I can create a virtual audio device (much like Aggregated device) but to which I can also assign the ports from the source device that I want (unlike I can do with aggregated device). Unfortunately the signal on Stomp USB was too low still (like I had a feeling before), but then I tried something crazy and I mapped both USB 5 and USB 6 outputs to the virtual device left channel which gives it just enough juice to be detected by RS properly. So now I can enjoy using the sounds from my HX Stomp and at the same time make RS recognize what I'm playing without using any extra cables, just my stomp connected with USB: I'm so happy :D The only downside is that LoopBack is a commercial software. I was actually using it already because of recording/streaming RS stuff so it wasn't a big issue for me. I actually have an older version of the software, but I think the new version works just the same.

I have HX Stomp working with Rocksmith using only USB on osx (using aggregate device named as "Rocksmith USB Guitar Adapter"). I first did encounter the same static noise problem mentioned earlier, but I'm not sure what fixed it. One thing I did for sure is that I downloaded hx stomp drivers from line 6 and installed them, but it might have been something else. I know I experienced inside rocksmith with the audio engine setting. Besides stomp, I have also used to Steinberg UR22mk2 usb audio interface with success. Even though I got this working now, I'm still not perfectly happy. First of all, the Stomp usb volume is way too low. I have stumbled to this while recording as well, and in order to fix it I have to edit the signal chain and set main L/R output "block" level to around +12db. Otherwise the signal is just too low! What I really would like to do is to make Rocksmith see the usb output port 5, which is the dry signal. That way I could use my effects as I wish, and still get clean signal for RS to get perfect note detection. Currently RS only works with usb port 1 (left/mono channel). Even if it would be somehow possible to make Rocksmith see the usb port 5 from stomp, it would definitely still suffer from the audio signal volume problem. I really hope we get a global setting for that in the future!