[gr34td3str0y3r]

So let me get this straight. 
For example an amp like the Fiio has an impedance, of <10ohm (from their website). So I should not use cans with an impedance level below 80 or it will create distortion? 
 
So lets take for example the O2 amp. It has an impedance of 0.54 ohms. So basicly anything on the market is okay in terms SQ? (but not necessarily volume since it only puts out 88mw for 600ohms).
The Schiit Magni is only 0.1ohm. 
 
I am sorry. Does this make it better? Or it's just a feature? 
 
It's only a 99$ amp.
 
The Fiio is a 80$ amp and is 10 ohms??? 1000x times the impedance? Is this on purpose? Why do they say that the amp is fine for "16-600 Ω" headphones? 
 
The Schiit Magni, Fiio F9, JDS O2 are all within 50 dollars of each other. Why the huge change in impedance?  .1 vs 10 vs .54

 

[DrSheep]

10 ohms going into a 32 ohms should still be fine given FiiO's power.  Yes you will get distortions to various degree, but if you are not too pickly about music being 100% neutral sounding, then you will be fine.  <1 ohms output impedance is good in general for impedance matching, however, you might hear statics or other interference due to circuit design, shielding, or IEM/headphone being too sensitive.
 
Here is an example of how the 8:1 impedance matching rule can be broken: V-MODA current flagship can is the M-100, which is 32 ohms.  However, when Val, V-MODA's CVO, set to design their new AMP the VERZA, he choose to tune the sound with the M-100, even when the VERZA has a ~10 output impedance.  This end up with a high end portable DAC/AMP that sounds great with low impedance IEMs / headphones while breaking the 8:1 rule at the same time.

 

[gr34td3str0y3r]

Funny you bring up the M100s. I just got mine 3 days ago. 
I love them. They are amazing. It's not that I need an amp, but I have a rather crappy laptop at work and listen to a lot of music there. 
I am thinking of getting a stand alone DAC (like ODAC). But I need an amp with that. 
I want to get a stand alone DAC because I don't intend for the M100s to be my last set of cans and I want some options down the line when it comes to amps. 
 
So for something like the m100s, for now, is the Schiit magni okay? 
I just need something to pair with ODAC, and I am not sure what my next set of cans will be. (I need closed cans for work) 
I would like a touch more base with my m100s on SOME music, but pretty much have my heart (and budget) set on the ODAC. 

 

[DrSheep]

Just saw your post on the other trend about the M-100, and the SM should be fine but I have never listened to it.  I am using AudioQuest DragonFly > M-100 as my reference for my PC, and for only $100 you will not be disappointed.  ODAC is aother god choice too.

 

[manbear]

I'm not sure which Fiio you are talking about, but if it has gain switches, the gain can affect the output impedance (hence the vague spec of <10 ohms). The output impedance may be 10 ohms at one gain setting, and less at another.

In any case, don't worry about it too much. The 1:8 ratio is just a guideline -- nothing terrible happens if your headphone impedance is below 80 ohms. You may not notice the distortion much, or it may even sound pleasant to you. It depends on your tastes and on the headphones.

As far as 0.1 vs. 0.54, neither one is really "better" than the other. Both are so low that it doesn't matter. It would be more appropriate to compare the amps in a broader sense, as in how do they sound, how is the build quality, etc.

 

[billybob_jcv]

Here's a couple of facts that will blow your mind:

- In the 1996 Standard, IEC 61938, the standard amplified output impedance for a headphone port was specified to be 120 ohms.

- The Beyerdynamic A1 headphone amp, which has list price of $999 (~$700 on Amazon) was tested to have an output impedance of 99 ohms.
http://www.innerfidelity.com/images/AllAmpsJuly2013.pdf