Okay now I'm really confused. A 4 pole TRRS male plug works in a 3 pole female TRS jack?
ADDENDUM:
Did some quick research as my assumption has just died

Okay, it appears the ground contact on a female jack is at the top of the sleeve (second ring area) rather than the base where the mic contact is for a TRRS plug. That allows a TRRS plug to work in a TRS jack.
Damn! Learned something new! LOL
I don't know much about plugs trs trrs balanced etc, but I know I just plug my puro into x3 without adapter
I was a bit concerned, because I tried plugging some headphones with trrs plug into the X3 and I wasn't able to get it going. Found the above posts. Tried a different headphone with ttrs plug and the plug went in fine and music resulted. Tried the first one again, and it's more of a challenge to get it in, but I did and music is resulting. Whew! I didn't want to have to deal with adapters (I had to do that with my 770 and it was a drag).
Now I just have to figure out when that pitch issue is supposed to occur and see if I can notice it (and if so, then rockbox).
I will say right off that I really like this about the X3:
- size (smaller than expected)
- feel (feels solid yet light)
- buttons buttons buttons (love all of those external controls)
And listening to some 24/96 Dire Staits with the Nighthawks off of the X3 is sounding quite nice and I think I'm going to be quite happy with the SQ.
So far so good!
Edit: oh yeah, I have to find a case for it. I like holsters with belt clips, so hopefully I can find something for it.
Edit2: huh, auto resume isn't continuing play from the same spot in the song but instead starts from the beginning of the track. That's a problem for me because I'm often listening to hour or two hour long tracks, and I want to resume at the proper spot. Rockbox, here I come!
Edit3: Wow - sounds really good!