The KOSS KTXPRO1 pair I received have the straight jack-plug. I have run them in for about maybe thirty hours. I played them on my Chord Mojo, and while they OK, they are probably not for me.
They do sort of make a replacement for my Sennheiser MX500, but nothing to get excited about. I guess if you're paying $9, it's about £7. However I paid nearly three times that, and to me they are only £20 worth of sound. Or maybe a little more.
They don't come anywhere close to my Grado SR225e. However there is a caveat with that. I feel the need to EQ my 255e, to reduce a little brightness. Once that is done the 225e are well ahead of the Koss. Granted the cost is massively more on the 225e.
The 225e make a sound leaning toward hi-fi. The Koss make a tonally OK sound, but they have some weird tones going on too. Making some sounds basically off. If I had no headphones to listen to my portable radio, I would probably keep them. However I still have some MX500, but only one pair. Therefor I am looking for something better hopefully, but more importantly something more suitable.
The Koss are a good size but I do not like that the cups don't turn and sit flat. While the AKGs do, they look like the cups might be quite large. I will have to find out. I am keen now to try the AKG Y50.
Maybe I did not let these KOSS KTXPRO1 run-in long enough. However I don't understand the excitement unless you really want cheap headphones. Under that circumstance they would be ideal.
The KOSS KTXPRO1 seemed to me, in summary:
a reasonable tone,
fairly balanced but a but crashy up top
a reasonable detail, but slightly warbly (Maybe to be expected at the price)
them not laying flat on the ears can be ignored
Sorry folks.
By the way, I popped into PC World to look for the AKG Y50, and couldn't find them. However I tired some £15 Goji (whatever) headphones. (I mistook them for some cheap AKG headphones.) They actually beat the Koss KTXPRO1 in some aspects for me.