I agree with Hellkitchen : the RSU 1.0.0 sound is the best Rockbox I have ever heard, not too bassy, clear and detailled. Nevertheless, I still prefer the "old" SU1.3.3 sound !   Note : I'm using 192kHz / 24 bits tracks with a Senn Momentum headset or with Hifiman RE400 IEM.

In my opinion, SU 1.3.3 gives the best sound (just before DOC final), SU 1.4 (and official 1.6) are not bright and clear.

@medimitry : the DX50 freezes in few seconds before music starts playing. I have no time to asks for library scan or any other command. I found how to revert back to SU 1.3.3 in the Rockbox thread.

Yes SUEX is not stable at all ! I had to use RKBatch Tool and to proceed as for Rockbox installation to flash 1.5 fw with cmw recovery, then use cmw to flash official 1.5 fw and SU1.3.3 to finish installation. A long afternoon of fear, I allready bricked some Android phones but they were old...

I think many readers of the DX50 firmware forum use SU (others use Rockbox).

I should say : no, I have a 32 ohms headphone, and I don't need.

I agree with PurpleAngel : Sansa Clip + FIIO amp should be the best choice. But the new FIIO would be about the same price and equivalent features within one device.

For sure, sound is much better than on phones ! I mainly listen to classical and jazz; a piano sonate, encoded in FLAC,  played by DX50 with neutral/cold IEM is a great pleasure.

Thanks to the Hifiman Company, I received my HE-400 within 5 days from my order and I do love their sound with my DX50 (sorry for the HM-700). I discover my large classical and jazz albums collection.

I agree with you, with some comments : 1. Gapless : fix is mandatory 2. Track display : mandatory 3. Info/album artwork display switch : nice to have 4. Replay Gain : nice to have 5. Screen wake-up : why not ? 6. I have no problems with my tags ... 7. Turn-on play restart : mandatory  ...

This is the coax adapter, to be plugged on top side of the DX50.

Yes, it is closer to 200 USD than 150, but I really want to avoid bassy headphones.

Sound signature is mainly a matter of taste, depending on the most listened music. As opera and vocal jazz are my prefered genres, I am looking for a signature as neutral as possible. The global sound depends also on the headphones, I use Hifiman RE400 (because my budget is limited), and I am...

SU 1.3.4 hasn't the same neutral sound signature I like in SU 1.3.3, so after a short test, I reverted to 1.3.3.