[FatmanSize48]

I switched back from the T70 to the 4.Ai, and....I have some bad news to report. On low gain and zero volume, the DX50 puts out a huge amount of hiss. The moment I unplug my IEMs, the hiss subsides. Surprisingly, there is the least amount of hiss at high gain. I have tried playing around with the volume controls, and have been able to confirm that the is is independent of volume. Because the T70 and HD800 are unaffected by this, I believe that the sensitivity of the 4.Ai is to blame. Can anyone else chime in on this?

 

[lin0003]

I formatted my 64GB SD card and put a few songs on and it plays!
Gonna fill it up now and see what happens. 

 

[Olanzky]

  I just received my DX50, and I must say I'm impressed. At $240, it outperforms my (overpriced) Arcam rPAC, a USB amp/DAC in every respect, save for overall build quality. Now, I don't mean to knock on the DX50's BQ at all as it is light years ahead of anything that Hifiman has put out, but it just can't match that solid little cube. Due to its outrageous OI, my 4.Ai was unlistenable with the rPAC--boomy bass and oddly recessed treble plagued the combo. Just as others have stated before, the 4.Ai/DX50 pairing is one made in budget-audiophile heaven. Though I haven't been able to listen to any earlier versions of iBasso's firmware, I have learned that the latest (1.1.6) update gives the DX50 a sound little warmer than neutral. As a bass-phobe (is that a word?), I initially found the DX50 and 4.Ai to be far to warm for my tastes. Fortunately, the (relatively) excellent onboard EQ managed to address and neutralize this issue. 
 
Satisfied with its performance with my 4.Ai-moderately-soon-to-be-UERM, I proceed to move on to what I view as the two other "major" headphone groups: (semi)portable closed and home open. I apologize to any on-ear owners who may take offense at this statement; though the on-ear segment is marketed as a separate entity, it is a spin-off of circumaural "full" sized cans. 
 
One would assume that the DX50 would have great difficulty in driving the 600 ohm T70 and 300 ohm HD800; this is not the case. Because of their impedance, these headphones, namely the HD800, are labeled, deceptively, as "difficult" to drive. Whether it be a testament to iBasso's amp design or the fact that these particular headphones are actually quite sensitive, the DX50 absolutely sings with the T70 and, to a slightly lesser extent, the HD800. While I could continue to gush on about how wonderful the T70/DX50 is, I must attempt to get back on track with what many of you are probably most interested in--a (semi)detailed "review" of the HD800/DX50...which I will write at a later time.  

 
what batch of DX50 did you get?

 

[FatmanSize48]

4th.
 
Edit: Did you see my second post, too?

 

[jamato8]

Where are you downloading the firmware from? I tried via the two links further back in the thread and the download is so slow that I can't get it done. 

 

[Jpfe8851]

Another undocumented improvement... The Volume buttons work immediately rather than the previous first click to activate the volume control then subsequent press to actually change the volume. Could this have been part of the phantom volume bug?

In any case it now functions conventionally and that's fine with me.

 

[Olanzky]

  4th.
 
Edit: Did you see my second post, too?

 
about the hiss yes. do they send you a confirmation reply and a tracking number before you got it? i was on the 4th batch as well.

 

[FatmanSize48]

   
about the hiss yes. do they send you a confirmation reply and a tracking number before you got it? i was on the 4th batch as well.

 
I purchased the unit from another head-fier, so, no. 

 

[tak-]

I purchased the unit from another head-fier, so, no. 

It's normal to hear the background noise. My only recommendation is to find a less sensitive pair of headphones or earphones. Initially I thought the hiss was most obvious on high gain, but after spending some time in a really quiet place, I found the mid to have less noise than low or high.

 

[JiPod]

In last place were the Shure SE535LE. Just too forward in the mids. The Shures shine on iPhones and iPods but quality DAPs show up their signature's failings.

 
Thanks for sharing.  Your findings with the SE535LE are unfortunate - my daily commute companion is the SE535LE paired with an NW-A867.  I was considering the DX50 but now am having second thoughts.  Did you try fiddling with the EQ? 

 

[Sorensiim]

  Have you guys noticed how the amplifier section of the DX50 doesn't behave like most of the other daps? Fiio X3 vs DX50 comparison:
 
 
Amp output impedance graphs DX50 vs X3:
 


 
 
Summary:
DX50 has an output impedance closer to 3 ohm, despite the claimed <0.5 ohm from ibasso. DX50 also has an impedance spike in the 100-20hz region, this means headphones with lower impedance have progressively less bass response as shown in the next graph, EG. a 10 ohm headphone with the DX50 will have around -10db less 20hz bass.
X3 has a low output impedance of 0.3 or lower ohms and isnt affected by the above, as such has a flat frequency response with all impedance phones.
 
http://personalaudio.ru/review/portable-audio/

I'm really surprised and pretty disappointed to see that the measured output impedance doesn't hold up to Ibasso's specs... Now we need to find out if this is the case for all DX50s or if the measured unit was a fluke - not that I see how one could deviate from the others in this regard, but then again - some report hiss, others don't.

 

[musicheaven]

Thanks for sharing.  Your findings with the SE535LE are unfortunate - my daily commute companion is the SE535LE paired with an NW-A867.  I was considering the DX50 but now am having second thoughts.  Did you try fiddling with the EQ? 

I have the SE535 atm and am pretty content, if you pair the DX50 with a good amp, for example a Pico slim, the combo is excellent. I am the kind of person who does not like to EQ the music but there is nothing wrong with doing it if you like it.

Edit: I also have a pair of SE215 and those ones seem to pair more easily than the SE535, I don't need the amp with them.

 

[Marleybob217]

  Have you guys noticed how the amplifier section of the DX50 doesn't behave like most of the other daps? Fiio X3 vs DX50 comparison:
 




 
Summary:
DX50 has a large advantage with 24 ohm and above headphones. Eg. Both used with 50 ohm headphones the DX50 can rack up 110mW at 2.5v, while the X3 only manages 30mW at 1.5v,
X3 has a large advantage with 16 ohm and below headphones. Eg. Both used with 10 ohm headphones the DX50 produces 40mW at 0.6v while the X3 produces 160mW at 1.5v.
 
Amp output impedance graphs DX50 vs X3:
 



 
Summary:
DX50 has an output impedance closer to 3 ohm, despite the claimed <0.5 ohm from ibasso. DX50 also has an impedance spike in the 100-20hz region, this means headphones with lower impedance have progressively less bass response as shown in the next graph, EG. a 10 ohm headphone with the DX50 will have around -10db less 20hz bass.
X3 has a low output impedance of 0.3 or lower ohms and isnt affected by the above, as such has a flat frequency response with all impedance phones.
 
Also there is the aspect of Line out implementation DX50 vs X3:
 


 
Summary:
DX50 has WAY less distortion than X3 through the line out.
 
Total Summary of DX50:
 
The DX50 comes with a quadtriple whammy of LAME ASS, if you want to use headphones with impedance lower than 24 ohms because:

1. Doesn't provide enough power, far less than the competition.
2. Doesnt provide enough voltage,  far less than the competition.
3. Has high ish output impedance,  far worse than the competition.
4. Bass is rolled of, more and more with lower and lower impedances.

 
The DX50 comes with a triple whammy of AWESOME, if you want to use headphones with impedance higher or at 24 ohms because:

1. WAY More power than all the competition.
2. WAY More voltage than the competition.
3. WAY less THD from Line out than the competition.

 
Original measurements from:
http://personalaudio.ru/review/portable-audio/

This might explain a lot of cases where people reported little bass and thin mids. 
Btw, what happened to the spoiler feature of head-fi?

 

[pnix]

  Are these the only changes?
Or did they just not care to write down minor changes and bugfixes?

Maybe I'm picky, but I do not like that the errors have been fixed are not documented. This is really no effort to bring a few points to paper and publish in the readme.

How does the playlist function? If it works then.

 

[Sorensiim]

DX50 + CIEMs is one hell of a portable combo...