[HiFiChris]

Image taken from InnerFidelity.

The AK100II has got an output impedance of ~2 Ohms and the SD2 shows an impedance raise in the (especially upper) treble which causes the SD2 to sound brighter than with a source that has got an output impednce of <1 Ohm.
On the balanced output the AK100II has got an output impedance of ~1 Ohm so you could get a balanced cable for your SD2 or pair it with an amp that has got a low output resistance.
Maybe someone with better physical and mathematical knowledge can calculate how much more dB of treble the SD2 will have when the source has got ~2 Ohms output impedance.

 

[Synthyss]

Ah.. Thanks. What about linum bax?

 

[HiFiChris]

I don't know about that cable as I am no fan of changing headphone cables in general so I can't provide any further information about that. Most important is getting a cable with a balanced jack so you can use your A&K's balanced output.
The alternative would be getting a headphone amp with a low output impedance.

 

[Synthyss]

I see. Thank you for letting me in to your knowledge ocean. It is highly appreciated. Many think that single end of ak100ii is better than balanced out. But I will follow your lead. I will purchase a balanced copper cable and try that out.

 

[HiFiChris]

The most significant changes in sound characteristics of IEMs with varying impedance response are caused by the source's output impedance as the.
2 Ohms aren't bad but <1 Ohm is desirable. Not every multi-driver IEM reacts the same, though.
 
You could also test your SD-2 on a source with low output impedance to perceive how it would sound being connected to such a source.
The latest generation MacBook Air, iPhone 4, Galaxy S4 and above, Galaxy Note 4 and above and HTC One M8 have got a pretty low output resistance.
 
I don't think that there will be huge differences in high frequency but they should be audible.
 
 
Just as an example:
That's the UE T.F10's impedance response:
 

 
 
 
That's how the UE T.F10 (a pretty critical IEM) reacts on different sources (click to enlarge):
 

 
As you can see, the MB Air has got the lowest output resistance, followed by the still very good Beyerdynamic a 200 p (1.1 Ohms, causing a dip in the upper highs of about 1.5dB which is only barely audible in quiet environment), followed by the PS Vita which is about at the level of the iPhone 4S (something near 2 Ohms if I am not mistaking) and followed by the Nexus 7 which is by far the worst of them with a very high impedance of propably 50 Ohms.
The signal path should also be free of coupling capacitors else you get a low frequency dip with low impedance headphones, even if the output resistance is low (Cowon J3, Colorfly, iPod Nano 1G.

 

[Synthyss]

Thanks again. I tried with iPhone 4. There were couple treble spikes but not as much as AK100II.
Also, I am trying with Z3 Compact it's identical to ip4. 
 
I know that 2-pin balanced linum cable will fix my problem but, I don't want to buy a 200 euro cable for an 300 euro earphone. That would be dumb.

 

[HiFiChris]

The iPhone is pretty much the optimum so I would suggest trying the Spinfit tips when they arrive and foam tips (you can also make DIY foam tips out of listening protection (http://www.head-fi.org/t/164830/foam-tips-for-the-altec-im716-phones http://lifehacker.com/5347245/make-comfortable-noise-isolating-earbuds-for-less-than-a-dollar)).
The disadvantage of foam tips is that you may perceive softened bass.

 

[xaddictionx]

The iPhone is pretty much the optimum so I would suggest trying the Spinfit tips when they arrive and foam tips (you can also make DIY foam tips out of listening protection (http://www.head-fi.org/t/164830/foam-tips-for-the-altec-im716-phones http://lifehacker.com/5347245/make-comfortable-noise-isolating-earbuds-for-less-than-a-dollar)).
The disadvantage of foam tips is that you may perceive softened bass.

I agree. I've paired the SD2 with sources such as X5, DX90 and iPhone 6+. IMO, the best match is with iPhone 6+ and I'm using the spinfit tips too.

 

[Synthyss]

If thats the case, I wont be satisfied with iphone's sound quality so I would need to sell these :/

 

[HiFiChris]

If you get a chance you could try the SD2 with the iPhone 6 as it's rumored to be rather on the dark side (I haven't had the 6 though) whilst keeping the output impedance low.
Though I'm not an every-device-sounds-different-person (if some parameters as impedance, noise and distortion are low) I perceive the iPhone 4's heighs as rather sharp and superficial (the same goes for the DX90) and the FiiO X3 as smoother and darker (those are rather small differences and I haven't blind tested them so that's only a very subjective perception).
 
I'm doing a frequency response measurement with the iPhone 4 and SD2 in just a second, wait for it.

 

[HiFiChris]

Drum roll please...
 
iPhone with SD2:

 
Only less than about 0.5dB more highs - most likely inaudible.
 
If changing the tips doesn't get you to where you want, the SD2 just isn't the right IEM for you.
 
One thing just came into my mind: propably you don't have a good seal?

 

[Synthyss]

But I love my SD2.. I just don't want to give away my perfect and comfortable fit, sweet presentation and guitar placements over a spiky treble  
I will do that diy thing later today. Spinfits are now being transported so it will take 7-10 days for them to arrive. And also, I will try subdue the treble by using the balanced out + pure copper cable. 
 
I won't give up on SD-2. 
 
and yes, I love them this much 

 
Thanks again Chris, you were very helpful..

 

[Rumpelstiltskin]

For sensible and good advice on cables try Ted of Teds Headfood. A look through The New Headphone Lounge thread would be useful for member comments of his gear.
I'do also recommend, from personal experience of the product, the Black Dragon (also the Silver Dragon for SD3) from Moon Audio.
Ted will have the lowest prices of the two. The Dragons are a more well known brand and do have good resale value. Good luck.

 

[daniel_hokkaido]

  But I love my SD2.. I just don't want to give away my perfect and comfortable fit, sweet presentation and guitar placements over a spiky treble  
I will do that diy thing later today. Spinfits are now being transported so it will take 7-10 days for them to arrive. And also, I will try subdue the treble by using the balanced out + pure copper cable. 
 
I won't give up on SD-2. 
 
and yes, I love them this much 

 
Thanks again Chris, you were very helpful..

 
Dude wait for the spinfits before launching into cables etc. 

 

[kamoteFX]

 
just arrived earlier this morning from thomann