First, the lightweight rig:
The X5 fits inside the closed OPPO PM-1 case without putting any strain on the zipper, and there's plenty of room for the cable and microSD cards, beneath.
As I wrote earlier, I think there's going to be a few OPPO PM-2's plugged into the FiiO X5 when they're released, as the bass energy and warmth of the X5's Headphone Out makes the efficient PM-1 sound a lot like an LCD-2 rev.1 (when used with a more neutral DAC and an amp that's more powerful).
For more transparency, plus improved dynamics, with less bass energy but more control, insert a 15V-powered Meier Stepance...
Some Head-Fi members might be familiar with my earlier "Travel Rigs." This is version 4.0 (below). They keep getting better as I try different solutions and nobody is more surprised than me that the FiiO X5 has replaced my Sony PCM-M10 as my portable source - after three and a half years (and having returned a HiFiMan HM801 along the way, after trying it under their gracious 15-day trial).
The Meier Stepdance is making a reappearance from version 1.0 of my Travel Rig, as it works so well with the X5 and PM-1:
HPRC 2400F case. (The Touch is just shown here, for scale.)
The FiiO X5 is sitting on top of two battery packs...
The OPA1612-equipped Meier Audio Corda Stepdance receives a maximum permissible 15VDC from the
Energizer XP8000 Li-Ion battery pack equipped with a Willy Cable WI15 inline voltage regulator. The external 15V supply voltage increases Stepdance output power to the headphones
by 123.7% vs. using a rechargeable 8.4V internal battery, and the OPA1612 datasheet shows that THD + Noise is as low as it gets when the supply voltage is at 15V.
In other words, the Stepdance is more than twice as powerful
and more transparent when running on regulated 15VDC power. Joy!
The other battery pack is a 10,000 mAH Anker Pro that I will keep connected to the X5 as a source of 5VDC when carrying this Travel Rig.