Can I get a few amp suggestions under $100 for my xb90? Currently using a Topping nx2 with my s6 phone. The nx2 doesn't sound any better or have more bass response than my phone by itself.
The nx2 was a terrible purchase. The charging port doesn't work, volume goes up and down by itself, and it crackles when you touch the volume dial.
If you must stay under $100, the Fiio E10k is decent for non-portable use--pretty much no hiss and the bass boost isn't terrible (but pushes upper bass more than I prefer). The Fiio E11k is okay for portable.
If you can save a bit more, the Cayin C5 is great, especially for portable use, but it also works for desktop. The one weakness it has as a desktop amp is that you can't leave it charging while in use on the desktop (Cayin says not to because of heat and audio distortion).