So.. Today, I finally attempted stacking the Plenue D with my Fiio E12A.. It does helps, but it's only a small improvement.. Yes, it's noticeable, which I guess is the point.. But for those who don't already own one, I wouldn't recommend you buy one specifically to stack with the Plenue D. (Unless you own a lot of headphones that are generally "Hard to drive." However, for the majority of us, It isn't needed, However, for those of us who just want that extra 8% increase in SQ, sure it helps.
Now, adding the E12A to something like a Nexus 7 tablet, HTC One X+, or Nokia Lumia 1520, etc.. Yes, it does wonders.. They are devices that were way underpowered. Not that the iPhone isn't.. It definitely is.. Hence why I own one.. But I hate stacking.. It's so cumbersome. The bands get in the way of the UI... Like I said, this is why I would rather just have a DAP do it all..
This isn't supposed to be anything to offend anyone, just inform those who may be seeking an addition 8-10% increase in SQ from their Plenue D.. If you want more out of Player, still recommend something with a True Line Out.. As using through the Headphone Out just make the Player act as a Pre-Amp, to alter color the sound, then just "Amplify" the sound with your amp.. Guess hence the name right.. Lol.. Over the weekend, I'll do a full review on the Plenue D. There aren't enough reviews on it.. Pretty pathetic honestly, it's a fantastic device, just needs more attention.