[adventurer 2015]

  well, external amps cannot be purely powered by line out, because as i get a grip on it, this is what they do, add power.
 
now, things are pretty clear, i had taken my walk around science forums, and i do not agree that all amps sound the same, i had enough listening with different equipment, from 30$ to 5000$ to know that different amps, DACs and other equipment sound different..
 
i was curious why something like e12a adds so much to the sound, while i was curious what was the difference between line out and headphone out, in the sense, that except for volume control, they seemed like doing the same thing, but now i understand that un-amplified signal does not carry lots of electrons, but carries their movement clearly... poower amps should add electrons to the thing.

Thank you for the reply. So if I get it right - at the phone's out for the headphones there is no way that power also comes out? 

 

[Dobrescu George]

from headphone output, comes out some power, but from line out comes less power than it comes from headphone output, this is why an amplifier needs a source of electricity to add power. this is what the amp uses the batterry for, adding power from the batterry to the signal.
 
about sound science, i really do think that ABX has no real merits, as i can hear differences between the same files listened on the same headphones at the same volumes, with the same source and cables. my mind would hear things extremely different at two different times, say  even if i listen two times in a row, i hear a song differently. Abx cannot work.
 
asking something on sound science is useless, because you will hear that e12 and e12a should sound the same, when the sound is extremely differenty between these two amps, which are my favourite amps too. 
 
i am a guy who is into solid state amps, and who does not like tube amps, and all solid state amps sounded extremely different, day and night difference, but all had similarities between them, which made solid state amping my first choice.

 

[Kokomo O]

I'm confused about why some are saying that the line out would be designed to have high, or relatively high, output impedance. On Fiio's listing of specs for the X5, there's only one output impedance listed, and that says <0.26 ohms, which is a perfectly respectable number. What I learned many years ago is that the design criteria to shoot for in designing electronic signal carrying devices is low, preferably near-zero, output impedance and high, as near infinite as possible, input impedance. So even though the line out is designed to feed into an amplifier's input, which should have high input impedance, it still should be as low as possible.
 
skerry, here's a way to think about impedance. Impedance is the analogue of electrical resistance that a varying electrical signal, like a musical signal, sees. In mathematical terms, it can get quite complex, with components that represent simple electrical resistance, which is a real number, as well as capacitance and inductance, which are imaginary numbers, but you don't really need to worry about that for these purposes. In its simplest terms, if you have a battery with voltage V, a resistor with resistance R, and you connect the resistor to the terminals of the battery, then you'll have current flowing through the resistor defined by the equation V=IR, or I=V/R. Similar, but more complex, equations work for alternating current or other varying current sources, and for circuits that have capacitors and inductors, the other main non-amplifying circuit elements, in them.
 
As for your question about why an amplifier needs power, the reason is that what it's doing is amplifying the signal that you put into it--by which I mean it is adding energy to that signal and making it louder, stronger, more powerful. Therefore, you need to give the amplifier energy. The power that an amplifier circuit has is called bias, and is usually referenced by its voltage. You can think of it in terms of pulling the flow of a river up a hill so that it can fall off of a higher waterfall than it would naturally fall from--you need energy to get the water up the hill.

 

[x RELIC x]

An ampflier only does one primary function, amplify a voltage signal so it can provide required volume and power to drive a load (headphone). It usually has 2 stages the gain stage and the ouput stage. The gain stage amplifies the voltage signal and the output stage provides the current needed to power different headphone loads.

How it sound is an interaction of different factors. e.g. load impedance, output impedance, noise/distortion it adds to the orginal signal and gain.

The line out is is the analog output from the DAC with an I/V (current to voltage) converter in front. It has high output impedance and meant to be connected to amplifiers which present itself as a very high load. 

You can plug your headphones directly to Line Out but it's not recommended for the following reasons.

1. High output impedance creates a very low damping factor which alters the frequency response of most headphones especially iems using balanced armature transducers.

2. It has very limited output power and cannot deliver enough power to drive most headphones.

The amplifier solves both problems and is the closest thing to the actual signal than what you are getting directly from Line Out.

If all factors mentioned above are equal with very low distortion/noise and enough power for a given headphone it's not impossible to think that amplifier may sound the same.

Curious how, as you say, the line out would have very limited output power yet blow your ears out when plugging headphones directly to it. Also, on the X5, when listening to the volume at near max through headphone out to an amp it sounds close to line out.

 

[Allucid]

I noticed people said that the Shozy Alien is better than the X5. It's definately not. Tried and tested myself, it has a bigger noise floor than the iPhone 5. I tried it out, and it's not bad and I'd happily keep it if I didn't have other issues.

 

[headwhacker]

Curious how, as you say, the line out would have very limited output power yet blow your ears out when plugging headphones directly to it. Also, on the X5, when listening to the volume at near max through headphone out to an amp it sounds close to line out.

 
iems and sensitive phones yes. But plug in something like an HD600 then tell me if it still going to blow your ears off. The line out is fixed at 1.5Vrms.

 

[x RELIC x]

iems and sensitive phones yes. But plug in something like an HD600 then tell me if it still going to blow your ears off. The line out is fixed at 1.5Vrms.

Ah. I knew that too.

 

[JaZZ]

Curious how, as you say, the line out would have very limited output power yet blow your ears out when plugging headphones directly to it. Also, on the X5, when listening to the volume at near max through headphone out to an amp it sounds close to line out.

 
I just tried the HD 650 through the X5's line out – it's quite loud and passably uncolored. So I suspect the output impedance is not that high, maybe 150 or 200 ohm. BTW, 1.5 V is not much below the standard voltage of CD players and DACs.
 
One of my listening variants in the past was having the Bel Canto DAC2 drive the HD 650, with just a 500 ohm potentiometer as an attenuator in between. A 2-volt line-out can drive headphones with ease, as long as its output impedance isn't higher than say 1/5 of the headphone impedance. The DAC2's output impedance is 15 or 20 ohm, if i recall correctly.

 

[Dobrescu George]

So line out is a clean power source that is just very loud... then how comes that e12a for example makes things better on x5? i mean, i can understand how e12 can add more power, but e12a does not hold more power, but makes everything better...

 

[Brooko]

  So line out is a clean power source that is just very loud... then how comes that e12a for example makes things better on x5? i mean, i can understand how e12 can add more power, but e12a does not hold more power, but makes everything better...

 
"Makes everything better" is a completely subjective term.  Sorry - I know you stated above how you thought ABX was useless - but try a blind volume matched (have to use a proper SPL meter to match) A/B test between X5 and X5 + E12A, with someone else randomly switching (so you don't know).  Then come back and tell us how that goes.
 
We're human.  More volume sounds better.  If we perceive something as being more expensive, more powerful, higher quality, our sighted impressions often influence our actual perceived sonic input.  Take away as many outside influences as you can - then just reply on listening to the audio, and get someone to switch.  Unless the amp itself is very coloured (and you enjoy that colouration more), of there is a massive difference between X5 H/O and L/O (some say there is - I don't hear it), then adding an E12a is not going to do a lot to headphones that don't need it.

 

[514077]

I bought a UHA-6II when I had an IPod160.  The external amp improved the IPod emensly for my taste.  We had these flat-screens to watch during dialysis and the external amp made those TVs listenable.  I assume the amp had lower impedance than either source.
Since the X5, I don't bother using the UHA any more as it's unnecessary.  I also assume the LO is a clearer path to an external amp, which is why I plug  LO into the car.
I also thought that when one refers to the 'DAC' output, that would be the co-ax output.
I know I had a point, but it escapes me.

 

[JaZZ]

There's another component which could play a role in terms of additional amps: the bass drop-off some (AC-coupled) headphone outputs show with low-impedance headphones – this due to undersized coupling capacitors. In any event the X5 doesn't, since it's AC coupled.

 

[AudioBear]

Brooko
 
Well for sure I did hear a difference and it was probably related to volume.  I found the HO needed to be turned way up whereas the line out needed to be attenuated.  I probably never compared them at equal volume. I think we can all agree that if volume isn't closely matched comparison is pointless.  I don't want to start a flame war like the one that's has been raging for years over at Sound Science but that may account for a lot of the difference people hear between amplifiers and other gear (kit).
 
Or not.  I have found amps i thought sounded different than others but I have not ABXed or even blind tested that.  My science PhD and 40+years of science research experience tell me that my feelings about amp differences may be subjective because my methods are suspect.  The only way to eliminate observer bias is to have both the test and the subject be blinded to the comparison being made.  If you think otherwise, you're wrong.  I know some of you think you can control your emotions and make absolutely unbiased judgements.  While some of you may be better at it than others, none of of you really can.  The psychology literature is very clear on this point.  If you're not double blind testing, you're not doing science.  Do not take that, however, as a claim that I don't think you can hear the difference between amps.  AFAIK what you hear is what you hear.  I can't hear what you're hearing, only you can.
 
ABX is a tool used in blind testing.  Like any tool if you don't use it right, you don't get good results.  Again, while testing must be blind or it's worthless, ABX testing isn't necessarily always the best tool.  Depends on the question you are asking.  If you want to ask if a 10 second fragment of music  played as X sounds closer to A or B, that is a valid question.  If you ask which is the better amp, that is maybe not the right question.  ABX only reveals if there are differences the listener can detect.  The problem is the brain hears and stores different fragments of a piece of music each time it is played and heard.  That's part of burn-in or break-in we were talking about a few pages ago.  The fact that we remember a different fragment of A and B when we hear them makes it very hard to compare them to X for which we have remembered some other fragment.  If it's not clear you can think or fragments as compressed audio files used by our brains.  Hence the need for repetitive testing which fatigues the subjects and adversely affects their judgement.  It is honestly very very hard to do a good objective test between any two pieces of gear.  The best tests are done for a number of repetitions repeated over several sessions.  This compensates for the different fragments remembered problem and provides more statistical power.  Arguing about testing is pointless. It can be done but is often not done correctly.
 
We also know some speakers (transducers) sound different with different amps (and some say DACs too).  Damping factor, input/output impedance matching, voltage or current limitations,  induced distortions etc all apparently can affect what we hear.  Our body perceives things differently from day-to-day.  We could go on and have the same discussion they are having ad infinitum over in the other forum.  
 
At the end of the day many of us have decided that for whatever reason different DACs, AMPs and especially transducers (I think we all agree on that) can sound different to us.  When we finally get one we like, or a set-up we like we stay with it until we are once again afflicted with upgrade-itis or switch-itis. It's really very unscientific but we get what we like to listen to if we are lucky.
 
Then too there is pride of ownership.  There is appreciation of looks and ergonomics. There is appreciation of build and packaging. There are in fact lots of other differences between 2 manufacturers products of the same kind than just how they sound.  And you have to admit that opening the box on a brand new anything is always fun.  Yes, there are lots of reasons to keep buying stuff.
 
But I'm not going to replace my X5 any time soon.  I don't even use an amp with it because my IEMs and phones all sound as good as I need them to sound.  That's really the point.  I don't need to test it because I'm satisfied with it. I have nothing to prove because it sounds good to me.  Thanks to all the reviewers and forum members whose comments put me on to the X% right as it came out. 
 
I'm ready to move on to another subject.
 
Twice now in the last week my X5 has started playing what I would call digital hash in the middle of a 24/96 FLAC track.  Stopping and starting didn't help it.  Moving to the next track solved the problem.  Is this just a high bit rate problem or what?  Is it a known behavior?  A sign something is going to go wrong?

 

[Dobrescu George]

  Brooko
 
Well for sure I did hear a difference and it was probably related to volume.  I found the HO needed to be turned way up whereas the line out needed to be attenuated.  I probably never compared them at equal volume. I think we can all agree that if volume isn't closely matched comparison is pointless.  I don't want to start a flame war like the one that's has been raging for years over at Sound Science but that may account for a lot of the difference people hear between amplifiers and other gear (kit).
 
Or not.  I have found amps i thought sounded different than others but I have not ABXed or even blind tested that.  My science PhD and 40+years of science research experience tell me that my feelings about amp differences may be subjective because my methods are suspect.  The only way to eliminate observer bias is to have both the test and the subject be blinded to the comparison being made.  If you think otherwise, you're wrong.  I know some of you think you can control your emotions and make absolutely unbiased judgements.  While some of you may be better at it than others, none of of you really can.  The psychology literature is very clear on this point.  If you're not double blind testing, you're not doing science.  Do not take that, however, as a claim that I don't think you can hear the difference between amps.  AFAIK what you hear is what you hear.  I can't hear what you're hearing, only you can.
 
ABX is a tool used in blind testing.  Like any tool if you don't use it right, you don't get good results.  Again, while testing must be blind or it's worthless, ABX testing isn't necessarily always the best tool.  Depends on the question you are asking.  If you want to ask if a 10 second fragment of music  played as X sounds closer to A or B, that is a valid question.  If you ask which is the better amp, that is maybe not the right question.  ABX only reveals if there are differences the listener can detect.  The problem is the brain hears and stores different fragments of a piece of music each time it is played and heard.  That's part of burn-in or break-in we were talking about a few pages ago.  The fact that we remember a different fragment of A and B when we hear them makes it very hard to compare them to X for which we have remembered some other fragment.  If it's not clear you can think or fragments as compressed audio files used by our brains.  Hence the need for repetitive testing which fatigues the subjects and adversely affects their judgement.  It is honestly very very hard to do a good objective test between any two pieces of gear.  The best tests are done for a number of repetitions repeated over several sessions.  This compensates for the different fragments remembered problem and provides more statistical power.  Arguing about testing is pointless. It can be done but is often not done correctly.
 
We also know some speakers (transducers) sound different with different amps (and some say DACs too).  Damping factor, input/output impedance matching, voltage or current limitations,  induced distortions etc all apparently can affect what we hear.  Our body perceives things differently from day-to-day.  We could go on and have the same discussion they are having ad infinitum over in the other forum.  
 
At the end of the day many of us have decided that for whatever reason different DACs, AMPs and especially transducers (I think we all agree on that) can sound different to us.  When we finally get one we like, or a set-up we like we stay with it until we are once again afflicted with upgrade-itis or switch-itis. It's really very unscientific but we get what we like to listen to if we are lucky.
 
Then too there is pride of ownership.  There is appreciation of looks and ergonomics. There is appreciation of build and packaging. There are in fact lots of other differences between 2 manufacturers products of the same kind than just how they sound.  And you have to admit that opening the box on a brand new anything is always fun.  Yes, there are lots of reasons to keep buying stuff.
 
But I'm not going to replace my X5 any time soon.  I don't even use an amp with it because my IEMs and phones all sound as good as I need them to sound.  That's really the point.  I don't need to test it because I'm satisfied with it. I have nothing to prove because it sounds good to me.  Thanks to all the reviewers and forum members whose comments put me on to the X% right as it came out. 
 
I'm ready to move on to another subject.
 
Twice now in the last week my X5 has started playing what I would call digital hash in the middle of a 24/96 FLAC track.  Stopping and starting didn't help it.  Moving to the next track solved the problem.  Is this just a high bit rate problem or what?  Is it a known behavior?  A sign something is going to go wrong?

i was totally content with x5, before listening to chord hugo, now there is no such thing as being totally content with what i own, before i will own hugo. It is still going to be hard to use while walking...
 
the problem you have, does it appear on computer? the file might be affected. Other than this, i would strongly suggest down-converting the file to 16/44, and see if the error persists..
 
another advice would be reseting via pin hole, if the problem persists, the file is damaged, or x5 cannor read the file.
 
 
 

   
"Makes everything better" is a completely subjective term.  Sorry - I know you stated above how you thought ABX was useless - but try a blind volume matched (have to use a proper SPL meter to match) A/B test between X5 and X5 + E12A, with someone else randomly switching (so you don't know).  Then come back and tell us how that goes.
 
We're human.  More volume sounds better.  If we perceive something as being more expensive, more powerful, higher quality, our sighted impressions often influence our actual perceived sonic input.  Take away as many outside influences as you can - then just reply on listening to the audio, and get someone to switch.  Unless the amp itself is very coloured (and you enjoy that colouration more), of there is a massive difference between X5 H/O and L/O (some say there is - I don't hear it), then adding an E12a is not going to do a lot to headphones that don't need it.

i totally get your point, more soundstage, better separation, clearer sound is what it adds...
 
man, i totally hear a song differently between listening it two times, even in a row, with the same equipment, and everything the same, the second time i listen it, i concentrate on other parts of it. what i perceive when testing equipment is done in such a way that i have no biases.
 
i test it two times, first volumes low-low then high-high then low-high-low-high, to observe if there are any differences.
 
i noticed that many sources sounded very similar at very low volumes, with very few making a difference. 
 
then i continue the test, using a track which i know from memory, because i sang it, re-created it, i purely know that track, i know enough about mics placing, instruments and what effects, and how the soundstage should sound like, this is why i have lower chances to fail. This works better than ABX specially if you know how it sounds live, and where the difference is. easier to spot.
 
whilst i cannot really put my finger on it, e12a seemed clearer, whilst e12 was totally transparent. i respect both, and both are amazing with x5.
 
i know that an ABX would be better, but, when i did it, there was much more difference for my ears, without knowing what was plugged in, i heared every device differently each time i tried. there was 0 coherent conclusion. So i even did x5, hugo, and some amps, without knowing what was plugged in, even if it was the same device twice in a row, it sounded extremely different, i searched for differences, and there always are.
 
X5 is the first device i own, that makes a song impress me every single time i listen to it, and it has been 9 months, with some songs listened more than 3-4 times a day, i can still fiind new things in songs. Human mind is amazing!

 

[AudioBear]

skerry2006aj
 
Thanks.  Will check all of those.  I stopped it and replayed it but it was the same which I thought at the time might have meant the file was corrupted but I haven't had a chance to download a new copy and try it.  Will check that out.  Never entered my mind but the chip could be the problem--or going through airport scanners.  May have nothing to do with the X5.
 
Last time i checked the master file was fine. 
 
Never want to hear Chord Hugo.  Could be too expensive if I do.