1. No 3.5 mm audio converter provided in the box ( have to purchase separately you’ll need atleast 5 ) 2. Output varies with the input signal volume, more amplification if you provide strong signal , but not a big problem. Rest is all Good , best for it’s price probably even better than behringer.
https://www.amazon.com/FIFINE-Headphone-Amplifier-Adapter-4x-Headphones/dp/B07QDN6JXG

