I have played with guitarix in the past, and having looked at some of its tube amp simulation code, I have great respect for the amount and quality of work that has gone into it. That said, in my opinion, its modeling capabilities are not on par with the main software sims out there.<p>My portable solution is an Intel Compute Stick coupled with a Vox AmPlug I/O for 24-bit/48KHz input, powered by a 10Ah powerbank. I use Bias FX 2, but one could use Amplitube or Helix Native just as easily. I attach these to my strap and it is completely out of the way when I'm playing. The whole setup on the hardware side cost me <$130, and in return I get the best modeling software can provide. It is however a pain to control.<p>Probably the "cleanest" portable solution would be the Boss Waza Air headphones. There are no wires at all!, and all modeling is done on the headphones themselves. At $400, they are on the expensive side though.<p>If one wanted a small amp, it is probably hard to beat Positive Grid's Spark, which can now be had for ~$200 and is also voice-controlled (a gimmick if you ask me). An even cheaper solution would one of Laney's Mini or MiniStack amps, which hook up to an Android or an iPhone that runs ToneBridge. That's a lot of effects and modeling for ~$60.