But how is docking any more efficient than regular line out? I feel like this is turning into an Apple-like experience...
 
The X5ii double-ing as a DAC is a pro for the X5; I don't see what the K5 has to do with it. Any other amp would be able to perform the same DAC/amp function. Don't mean to be hard on ya, just trying to figure out the pros of this device.

@avitron142 It's the convenience of docking FiiO DAPs without a need for any connecting wires (dock mates with micro-usb connector at the base), being able to charge the DAP while it's docked, and then driving demanding headphones.  With X7 you can also control it with optional bluetooth remote without a need to tap touch screen or playback hw buttons.  Just a convenience, where for example you can keep FiiO DAPs docked and turn them on/off when turning the K5. Probably pair up with X7 is the most convenient.  When you are on the go, use your DAP with your IEMs.  When you get home, dock it and use it with your cans.  Or if it's near your computer, hook up K5 to your usb port.  No need to connect any usb cables or 3.5mm LO interconnects directly to your DAP.  Just plug and unplug the DAP.

I hear. Cables haven't been such an annoyance for me, but I can understand the convenience.

@avitron142 : and not just audio cable hook up, but also discharging battery and keeping it plugged in.  For me personally, K5 makes a perfect sense for use with X7.  Btw, FiiO is also coming out with a simple basic charging stand/dock to charge their DAPs and to provide Line Out for pair up with a more serious external amp.

@twister6 Just for the charging function? That must be a serious pro then. As a DAC/amp user (and not a DAP/amp), I didn't realize the potential for such a device. Just one thing I'm not sure I'm getting, what would be the difference between a simple charging dock and a micro-USB cable? The dock has to be connected to the wall anyway, right? And anyway the X7 has a line-out, so there isn't any improvement there either.

@avitron142 : Check it out in James' post here: http://www.head-fi.org/t/713735/fiio-x7-dxd-dsd-384k-64b-ess9018-android-amp-module-design-call-for-3rd-party-amp-module-developers/8715#post_12294827 with X7 docked to the left of the keyboard (and BT remote next to it).
 
Dock keeps your DAP upright, remember, X7 is like your "smartphone", and you don't need to fumble around when plugging the cable, just set it into the dock and remove it when done.  Similar to A&K charging cradle

avitron142, fiio's ecosystem

Anyone please, compare this with SMSL VA2

Great Picture as well as Review,
 
My que here when,
 
1.Fiio DAP (X3/5/7) use as DAC and pulling audio signal from PC - There screen can be turned OFF - Right ?
2.Any hint or news when and where those 11 Pin micro usb cable available to purchase to use 'Dock In' port at the back of the K5 ? Or they already available from Fiio or other reputed brand ? 

@Ab10 : you should be able to turn the screen off, I didn't personally since I was monitoring the screen to make sure DAP is charging and I can see the bit rate/depth.  No news about the cable, CNY brings everything to a halt

I really like this idea of a universal (within the manufacturer's wares anyway) docking concept. My last exposure to it was with the original E7 and thought it was a great idea but figured they might drop it after a while. Nice to see they've stuck with it.

Too bad it isn't compatible with the original X5.

So if I don't dock my X1, can I go USB to balanced out to monitor speakers? Or does the balanced out only work with X5ii & X7 as you state?
 
When your headphones are in does it cut sound to the RCA & Balanced line-outs?
 
Kind of new to all this...

excellent review.
Hello I am Laura. sorry to interrupt you. Could you review our BT earphones? here is my email: laura@ivafee.com
I don't know how to get touch with you.

Will this work with Fiio X5?

Very good review, you brought up some very nice points.  In one of your pictures, the grain lever seems more recessed than the input switch.  So much so that it may be hard to "click" into place.  Is that an accurate statement?
 
Nice work, nice accessory to consider as a "Jack of all Trades".

@DaddyMojo : sorry, maybe it was a bad angle in the picture with a macro zoom.  They are identical, gain and input switches.

Would you recommend using this amp with Sennheiser HD650s?

Can you use this straight up as a headphone amp+dac connected to pc via usb Without docking anything? Just the k5 and the PC with Sennheiser HD 650 will it work?

How does the analog audio get out from the Fiio DAP-DAC if its connected to the dock-amp via USB only???