I am not 100% done with my review, which will be here, but here is my write-up so far:
Sound quality: Depending on the headphone used, the technical improvements vs. the iPhone 4S range from small to significant. The 4S sounds good as is for what it is, but lacks resolution and doesn’t have great control in the bass region which results in the good but not great sound. The i.Fuzen has quite a bit more control than the iPhone 4S which leads to more clarity, transparency, and instrument separation, but it depends on how controlled the drivers are to start as BA drivers tend to be easier to control. While the i.Fuzen has a higher resolution with the 4S, the difference isn’t all that large and the differences are in larger part a result of the amp control than resolution and the difference in presentation makes an equally large difference to the sound, opening up the sound more. I don't currently own any amps that have all that close of a price point, but I was pleasantly surprised by the i.Fuzen given the price and my previous experience with similarly priced amps.






