[Stekos]

I just got my new X3, I ordered the "package" deal from Amazon, got the X3, a 64GB Sandisk card and a "digital cable".
 
First, about the X3.  Looks awesome, great, professional looking package.  Top notch build. 
 
Connected it to my laptop and the X3 drive popped up right away, it has the demo album from HDTracks and a bunch of PDF documents. 
 
Copied off the docs, and deleted them from the X3's built-in memory, and filled the rest with music files.
 
I've got about 100GB of 96/24 and 192/24 FLAC files from HDTracks.  The main reason I bought the X3 was so I could FINALLY carry these around with me.
 
Popped in the 64GB card, and formatted it, and copied another ~63GB over.  Estimates were about 2 hours to fill the card, I tried it in the X3, plugged into an external multi-card reader, and a card reader in the card-slot.  Seems like copy speed is the same all 3 ways.
 
Still working on editing and organizing my files.  The X3 is like the MP3 player built into some cars, it just sees the folders and lists the files as they come up.
 
Did a quick test via headphone jack, audio plays fine.
 
What I really want to do is connect the digital-out to the digital-in on my Fiio E17.  Not entirely sure what type of cable to use.  The cable that I got with my kit that was called "digital cable" in the Amazon listing is a standard stereo 3.5MM plug, about 4" long, perfect size to go from the X3 to E17.  Connected that up, moved the headphone jack to the E17, changed the input on the E17 to Digital, and hit play on the X3.  Get good audio out.  So I know it works.  Just want to confirm that this is correct.
 
There are a bunch of different ways to do digital-digital on devices.  On my Macbook Pro, you can plug an optical jack into the 3.5MM headphone jack, and it works as a digital/optical out.  The X3 comes with a MONO 3.5MM jack to COAX cable, guessing that is to convert the digital to a standard COAX digital, but it's MONO, not STEREO. 
 
So, overall, it does work.  I'm just confused about the different cable types and want to make sure that the 3.5MM stereo to 3.5MM stereo plug is the correct way to connect the X3 to the E17.
 
Thanks guys.
 
I'll post a more detailed review of the X3 after I get a chance to really use it.  So far I've just copied over some/most of my FLAC files and tested the audio.

 

[PurpleAngel]

  There are a bunch of different ways to do digital-digital on devices.  On my Macbook Pro, you can plug an optical jack into the 3.5MM headphone jack, and it works as a digital/optical out.  The X3 comes with a MONO 3.5MM jack to COAX cable, guessing that is to convert the digital to a standard COAX digital, but it's MONO, not STEREO. 
So, overall, it does work.  I'm just confused about the different cable types and want to make sure that the 3.5MM stereo to 3.5MM stereo plug is the correct way to connect the X3 to the E17.

 
The (S/PDIF) digital signal only needs a single (mono) channel to transfer it's signal.
The digital signal can have multible audio tracks embedded into it's signal.
In this case your digital signal has 2-channels (stereo music) embedded into it (from Mac to X3)
The Macbook's single headphone jack can output an analog audio signal or an optical (digital) audio signal.
Coax (coaxial) is an electrical (digital) audio signal (which the Mac's headphone jack does not use).
Optical and coaxial transfer the same information, but one does it with light (optical) the other with electricity (coaxial).