[f4phantom2500]

Hey guys,

I tried plugging in my DN2000J into the line out port of my Fiio X3 1st gen, and lo and behold, the output volume is within my range of listening levels: I can comfortably listen to this for over the length of an album, probably for hours if I had as much time to be blissfully unaware of my surroundings.

Off hand, the audio seems a bit more resolving than through the headphone out, and I assume this bypasses any coloration inherent of the headphone amp of the player. But seeing as I'm sending the player's line output directly to the headphones, is there any inherent reason I shouldn't do this? Am I somehow risking damaging the headphones or player? As best I can tell, I'm essentially trading volume control for a bit of extra resolution. So it seems pretty much like a win to me, a "free upgrade" to SQ if you will.

 

[H20Fidelity]

With low impedance IEMs like 2000J its best to use a headphone out with low output impedance. The output impedance from a sources line out tends to be quite a bit higher, sometimes alot. You're not hurting anything by using the line out, it won't break your IEMs. You could even go one step further and connect an inline volume control if you want.
 
Purists will tell you its always best to use the players headphone out as the line out is bypassing the internal amp section of the source and the output impedance mentioned. I myself use the headphone out always but you're not hurting anything if the volume is suitable enough.

 

[MindsMirror]

I agree that it won't cause any harm.
 
In theory it might have a lower noise floor this way since the opportunity for the amp to add noise is eliminated. The line-out may produce higher distortion.
 
The sound signature will be changed by the output impedance. The impedance graph of the DN2000J on Innerfidelity shows that the high frequency response will increase with a high output impedance, so it should sound brighter. That most likely explains your impression of more resolution. Normally you would consider the response with low output impedance to be the correct one, but good or bad is subjective so it's perfectly fine to say it sounds better with the high impedance line-out.

 

[f4phantom2500]

quote name="H20Fidelity" url="/t/809022/plugging-headphones-into-line-out-an-absolute-no-no#post_12598936"]With low impedance IEMs like 2000J its best to use a headphone out with low output impedance. The output impedance from a sources line out tends to be quite a bit higher, sometimes alot. You're not hurting anything by using the line out, it won't break your IEMs.
[/quote]

I dont think I fully understand. Can you elaborate further on why it is best to use the headphone out, if the line out is indeed safe and at a good listening level? Does it have to do with the other comment made about distortion? Because I cant really hear any more distortion. To me the imaging and separation seems a bit better through the line out, across the spectrum. It does not seem very difficult to notice textures of bass drum notes when layered with deep bass lines and various synthesizers become more defined as individual texture, whereas the headphone out sounds a bit amorphic in comparison.

It does sound brighter, but the imaging and separation seems more precise as well.

I remember reading about an X3 mod wherein the opamp to amplify the signal for the headphone out was swapped for one that offered a more neutral signature, as apparently the stock one is on the warm side and not quite as detailed compared to its replacement. The Wolfson DAC has a nice sound on its own, although it too is on the warm side.

The way I see it, if I were using an amp I'd use the line out to bypass the internal amplifier in order to shorten the signal path. In fact, it is for that same reason that it seems to me the line out would be the more 'purist' approach, provided the signal is at a good volume. So, I'm not convinced that the line out doesn't sound better than the headphone out, at least with these iems and dap.

Either way, thank you both for your insights and for your reassurance that it won't cause any harm.