JLEKIt is switchable, so 230V is not a problem. Overall, I would recommend it to a warm sounding or V-shaped sounding headphone, it is very neutral and detailed, but not a very good match for bright/analytical headphones. Sound tends to lack body and any "fun" factor in that case. I prefer Schiit Lyr with both Hifiman HE-400i and AKG K553. But I still keep Nuforce for future headphones, it is a fine amp :)
Thank`s