[boris_mikhaylov]

  Thank you Boris for the tests. Its difficult for me to compare them as they are in different formats and i don't have the technical knowledge to do it properly.
 
Can you give us digest of your findings? A subjective opinion on the quality of sound will also be great!

 
At first, my disappointment of Scarlett 2i4 is a worse recording of line level signal.
What about playback with 300 Ohm headphones, like a Sennheiser HD 600, I think:
The Xonar Essence STX is simply the best for it price even without amplifier, but it is internal.
The Xonar Essence One is exelent, but for that price may be better use a receiver/DAC with S/PDIF or HDMI input.
I use (before and now) the Creative Sound Blaster X-Fi HD USB card ( http://borisgermanov.blogspot.ru/2013/11/creative-sound-blaster-x-fi-hd-sound.html ) with Corda Arietta Amplifier ( http://borisgermanov.blogspot.ru/2012/05/meier-audio-corda-arietta-headphone.html ).
It sounds little better then 2i4 without amp. Both 2i4 and X-Fi without amp with HD600 are the same. That is for me. I'm not a cool audiophile - I can't hear above 16kHz .
I think, the Scarlet is good choice for using active monitors with long balanced cables (or for recording of Hi-Z sources and microphones without analog mixer).
I know, that this words doesn't help to any choice, but if I be able to find an any RMAA tests of the scarlett 2i4 I was not buy it...

 

[DanSun]

Thank you Boris,
I see that as a headphone amp the 2i4 will not work well for high impedance phones.
Were you able to compare the balanced output between the Xonars and the 2i4? Quality of the sound coming out of the DAC and general performace as a DAC?

 

[DanSun]

Did you find in your measurements something that the 2i4 does bad or better comparing to the xonars? Both for the balanced and unbalanced outputs. Thank you again.

 

[Tablix]

The reason I use the 2i4 is portability and mic preamps, and more than satisfactory playback.  I can move between laptop and desktop in under a minute and the mic pre-amps are very well respected.  Neither of the other devices has phantom power so not designed for recording.
 
I could use a sound card for playback but the difference is so ridiculously small that even with high end pro monitors most people would struggle to point out flaws, only slight differences.
 
My advice is buy what is convenient for you, be it internal or external, pro audio or consumer.  Audio interfaces dont always look great compared to a high end audiophile dac, and internal is one less box of tricks on your desk.  These days the audible differences are not as huge as some would lead you to believe.
 
All IMHO

 

[DanSun]

I just got it. In the next weeks I will be testing against the odac o2 combo with HD600 headphones. Will try a fiio x3 as dac also. Will try a pair of yamaha ns 1000 speakers and a belles 250 and a classe DR 10. Im really courios about the quality of sound that this Focusrite Scarlett 2i4 can delivery.

 

[pss395]

I also just bought a KRK RP6G2 and now looking for a Dac.
Seems like I got 2 option: go with the Scarlett 2i2 or buy the HifimeDIY Sabre 2 Dac, which crazymonkey suggested me.
So in your opinion, which one is better for strictly music listening? I don't need to record or mixing or anything
 
And Dansun, I'm really looking forward to your opinion on those Scarlett  

 

[boris_mikhaylov]

  Did you find in your measurements something that the 2i4 does bad or better comparing to the xonars? Both for the balanced and unbalanced outputs. Thank you again.

My measurements of the Xonar STX and Scarlett 2i4 shows that Xonar is better for both, line and headphone outputs.
Xonar STX have not balanced outputs and it's PCI-E interface.
Xonar STX has a good headamp for high impedance headphones - better than Scarlett 2i4 and Creative X-Fi HD USB has (just heared, not measured).
I see third party (iXBT) tests of the Xonar One (USB)... Still better than 2i4.
Xonar One has balanced outputs and has no analog inputs and 3 times expensive.
May be a some good amp with not expensive DAC with S/PDIF input will be better for headphones for less money? I did not find yet.
 
For recordig... When size does matter too?...
...You can choose what you choose to choose.

 

[boris_mikhaylov]

  I also just bought a KRK RP6G2 and now looking for a Dac.
Seems like I got 2 option: go with the Scarlett 2i2 or buy the HifimeDIY Sabre 2 Dac, which crazymonkey suggested me.
So in your opinion, which one is better for strictly music listening? I don't need to record or mixing or anything

Be aware about Windows MME output.
Focusrite drivers supports 16-bits only. See http://borisgermanov.blogspot.ru/2014/03/focusrite-scarlett-2i4-rmaa-test-report.html - S2 and S3 - 104 and 98 dB dynamic range. 24-bit depth supported through ASIO only.
Even if a source record is a 16-bit, you can hear a difference of playback by foobar2000 (internal processing is 64-bit floating point), for example, especially with some set of DSPs.

 

[RonaldDumsfeld]

OP wanted 'strictly music listening'.
 
Even if this claim is true since almost all distributed music is 16bit he could use the MME drivers if he wanted (why not use ASIO?) and it wouldn't make any difference. Even assuming it would anyway. 
 
Focusrite make good gear for a fair price. Decently supported.

 

[pss395]

Thanks. I think I have to go the Focusrite part now because I really need the volume control. Window volume control suck.
But how's about the sound signature of the 2i2? The SQ of the headphone out? 

 

[boris_mikhaylov]

  Thanks. I think I have to go the Focusrite part now because I really need the volume control. Window volume control suck.
But how's about the sound signature of the 2i2? The SQ of the headphone out? 

I think that 2i2 schematic is near to 2i4, so about 2i4 my opinion:
The sound signature is good enough.
The headphone output is build, I think ( see internals http://borisgermanov.blogspot.com/2013/07/focusrite-scarlett-2i4-inside.html ), on the JRC 4565 OpAmps ( see specifications http://semicon.njr.co.jp/eng/product/opamp/NJM4565.html ).
I can't find a voltage converter from USB DC +5V to a higher (+-) voltage.
How do you think it may drives a heavy headphones?
 
P.S.
Good for Denon AH-D1001 (25 Ohm)
 
P.P.S
If you not need recording from microphones why $150 Scarlett?
May be $100 Behringer? I think they differ only by mic preamps...

 

[pss395]

I think that 2i2 schematic is near to 2i4, so about 2i4 my opinion:
The sound signature is good enough.
The headphone output is build, I think ( see internals http://borisgermanov.blogspot.com/2013/07/focusrite-scarlett-2i4-inside.html ), on the JRC 4565 OpAmps ( see specifications http://semicon.njr.co.jp/eng/product/opamp/NJM4565.html ).
I can't find a voltage converter from USB DC +5V to a higher (+-) voltage.
How do you think it may drives a heavy headphones?

P.S.
Good for Denon AH-D1001 (25 Ohm)

P.P.S
If you not need recording from microphones why $150 Scarlett?
May be $100 Behringer? I think they differ only by mic preamps...

Which Behringer product? I select Scarlett only because that's the only interface I know.

 

[boris_mikhaylov]

 

I think that 2i2 schematic is near to 2i4, so about 2i4 my opinion:
The sound signature is good enough.
The headphone output is build, I think ( see internals http://borisgermanov.blogspot.com/2013/07/focusrite-scarlett-2i4-inside.html ), on the JRC 4565 OpAmps ( see specifications http://semicon.njr.co.jp/eng/product/opamp/NJM4565.html ).
I can't find a voltage converter from USB DC +5V to a higher (+-) voltage.
How do you think it may drives a heavy headphones?

P.S.
Good for Denon AH-D1001 (25 Ohm)

P.P.S
If you not need recording from microphones why $150 Scarlett?
May be $100 Behringer? I think they differ only by mic preamps...

Which Behringer product? I select Scarlett only because that's the only interface I know.

I was wrong two times.
At first, about absence of DC-DC converter because a presence of phantom mic power.
At second, $100 Behringer UMC22 is a 48 kHz interface, but UMC202 or UMC204 is a same cost like Focusrite's interfaces.
Anyway, why pay for well marketed recording preamps?
Ok, Scarlett 2i2 is a good choice for you, if you not care about sound of headphones or you like or have some easy driven ones,
but better give a 2 times more money for a Xonar Essence STU ( http://www.asus.com/us/Sound_Cards_and_DigitaltoAnalog_Converters/Xonar_Essence_STU/ ). ...where this device was when I was ...!

 

[pss395]

  I was wrong two times.
At first, about absence of DC-DC converter because a presence of phantom mic power.
At second, $100 Behringer UMC22 is a 48 kHz interface, but UMC202 or UMC204 is a same cost like Focusrite's interfaces.
Anyway, why pay for well marketed recording preamps?
Ok, Scarlett 2i2 is a good choice for you, if you not care about sound of headphones or you like or have some easy driven ones,
but better give a 2 times more money for a Xonar Essence STU ( http://www.asus.com/us/Sound_Cards_and_DigitaltoAnalog_Converters/Xonar_Essence_STU/ ). ...where this device was when I was ...!

You give me a really hard time there the Xonar STU is way beyond my budget. 
Also, I've found the Audioengine D1 Dac, I think their headphone out is better than the 2i2. But does the volume knob also control the volume level of the RCA speaker out?

 

[Xyrium]

Love my 2i2. I use the Instrument input for my guitar into various VSTs. I take the balanced outs into a DriveRack 260, which feeds a pair of Focal Solo6 Be sats and Rhythmik 12" subs. The sound is phenomenal. The soundstage is accurate, if not slightly forward compared to either my old Emu 1212 or the 1616M (both of which will be for sale later this week). I have a separate headphone amp though. So, if you really need this for headphones, I'd probably suggest something that isn't bus powered to begin with.