I just got the new FIIO power supply PL50 ... I was quite doubtful it would bring some real improvement, like I was thinking after a while with the iFi iPower Elite 12V (I didn't do any more some A/B comparison for a long time, I am just using the iPower Elite at home or an external Monolith Thx887 amp)...
Last year, when I bought the iPower Elite, I made some short A/B comparison with the Fiio standard power supply when activating the Headphone Enhanced Mode, I was feeling it had some small enhanced impacts without being totally sure it was not just in my brain like a pure placebo effect...
So this time, in my office, I tried for a longer time to switch between the standard power supply and this brand new PL50.... Though it can still be a placebo effect, this time, I feel quite easy to find some enhancement in low /ultra low frequencies .. maybe deeper in ultra lows and in lows, kicks seems really more pronounced/faster.
Though I still don't trust my "listening brain" so much
, as the demanding price is not crazy at all, I would say, it seems rather worth to give a real try to such bulky and heavy power supply, particularly with Headphones like DCA Stealth which are almost distortion free in lows and ultra lows.
It's far more than a full year now that I use the DCA Stealth and the FIIO M17, and I still feel this combo is really enjoyable to listen music with the best possible sound quality and comfort anywhere we want to do it at home, and even get some enhancement when plugged to an external power supply like PL50 and maybe the iFi iPower Elite too.
I didn't make some A/B comparison with my little external amp monolith THX887 (2x6W), but I am not sure with the PL50, the gap is almost filled now.
Actually, I have to say that my "going outside home" reference is not really the M17, but with the DCA Stealth, I mainly use my modded old Sony NW-WM1A (by Nayparm with a load of huge capacitors) and a Centrance Ampersand (2x3W), this hotel combo, can be easily switched to a truly pocketable standalone WM1A + a tiny Planar IEM Tangzu Zetian Wu to walk in the street/metro/trains..
So in short, it's rather difficult to compare directly and avoid totally some placebo effect, but, I would rank my combos in this order :
1) Elite ipower or PL50 (not really tested) + Fiio M17+ Monolith THX887 (XLR balanced input and output) + DCA Stealth
2) PL50 + Fiio M17 + DCA Stealth
3) Elite Power + Fiio M17 + DCA Stealth (can be probably on par with PL50, but I just felt the gap between PL50 and Fiio standard power supply was quite clearer than with iPower Elite when I compared last year)
4) Standard 12V Power supply + Fiio M17 + DCA Stealth or the surprising combo WM1A(Nayparm mod) + Centrance Ampersand + DCA Stealth (my best "still portable" combo)
Then, with a significant step behind
5) Fiio M17 + DCA Stealth (but need some PEQ to compensate the loss of low frequencies under 30hz, though it can't help for speed impacts feeling in mid lows/lows).
and even more behind
6 A&K Kann Alpha or Centrance M8V2 + DCA Stealth (both can clip easily with too much low frequencies like in Cradle to the Grave of Max Richter) but can be quite enjoyable most of the time at a moderate Sound Pressure Level.