[blades]

Near perfection at any rate.  To me spending money on outboard DAC's is pretty silly.  There isn't a bit of difference in sound quality between one DAC and another.  Hearing bias will work against your wallet to be sure.   Spend your money on transducers (speakers, headphones etc.)

 

[krismusic]

My Sennheiser HD-600's are high impedance (based on higher voltage) and require more than 1VRMS to get them to a "rocking out" level.  

I use the O2 with my 5S and HD600's. As far as I can tell it simply increases the available volume. The presentation is so good that I am not interested in spending hundreds trying to improve it. I took on board the recommendation that I have read in Sound Science several times and sank all available cash into a pair of headphones. JH13's. With the 5S I don't think I am going any further.

 

[bigshot]

I had a set of HD590s and I read that they were on the edge of needing amping. So I bought an amp. No sound quality difference. It just made them louder. My current headphones (Oppo PM1) don't benefit at all from amping either. I just plug them directly into my iMac. Simplicity itself.

 

[cjl]

To give a counterexample to the last two points, I genuinely did need an amp and a DAC for my Denon D5000s at work. How did I know? The (pitiful) headphone output from my work computer had a very audible hiss when not playing anything, and even at 100% volume, it didn't get nearly loud enough. An O2/ODAC solved both of these problems. Aside from the volume and noise though, the sound isn't any different.

 

[krismusic]

Although you say it's a counter example, you seem to have arrived at the same conclusion. No fundamental difference in SQ or soundstage, if I understand you correctly. Interesting that this is the case with the ODAC. How are you using the ODAC with the phone? I didn't think it would be Apple enabled.

 

[cjl]

Although you say it's a counter example, you seem to have arrived at the same conclusion. No fundamental difference in SQ or soundstage, if I understand you correctly. Interesting that this is the case with the ODAC. How are you using the ODAC with the phone? I didn't think it would be Apple enabled.

It's a counterexample because I did genuinely need an ODAC/O2 for my computer due to poor sound quality. It's obvious when it is needed though (and based on my understanding, the iDevices should not need an external dac ever, and should only need an amp with fairly challenging loads like an HE-6).
 
As for my ODAC, I use it with my PC at work. Sorry if that was at all unclear...

 

[krismusic]

As for my ODAC, I use it with my PC at work. Sorry if that was at all unclear...

Not unclear. I just need to read more carefully!
It's just that you say the sound did not change. I'm suprised you would be able to identify the sound quality through the noise and lack of volume.

 

[meurglys0]

My girlfirrend is considering getting an Iphone 5s or an Ipod Touch 5G. I would like to ask a few questions...
 
1) Is there any noticable difference between the two in means of sound alone?
 
2) How do they compare with Cowon (I believe the Cowon sound is pretty much the same on all models)?
 
3) My girlfriend is planning to buy portable headphones (not IEMs or buds) to be used without an amp or any other external device, so will buying an Iphone 5S or a Touch 5G limit her options with headphones due to an impedance issue? Will these players be able to drive most portable headphones? I don't know anything about this impedance issue, so will you please enlighten me about the matter?
 
Thanks in advance for your valuable replies...

 

[SilverEars]

  My girlfirrend is considering getting an Iphone 5s or an Ipod Touch 5G. I would like to ask a few questions...
 
1) Is there any noticable difference between the two in means of sound alone?
 
2) How do they compare with Cowon (I believe the Cowon sound is pretty much the same on all models)?
 
3) My girlfriend is planning to buy portable headphones (not IEMs or buds) to be used without an amp or any other external device, so will buying an Iphone 5S or a Touch 5G limit her options with headphones due to an impedance issue? Will these players be able to drive most portable headphones? I don't know anything about this impedance issue, so will you please enlighten me about the matter?
 
Thanks in advance for your valuable replies...

I've heard Cowon D2 has capacitive coupled headphone out which rolls off sub bass.  Somebody at DIY section has replaced caps to flaten the response.
 

 
http://www.head-fi.org/t/638056/cowon-d2-hardware-mod-zning-mod
 
As far as output impedance affecting the iem has to do with the FR changes, dynamic driver iems are approximately flat impedance so it should not be affect by output impedance.  BA driver iems has skewy impedance characteristic.  With BA, the output of the DAP with skew if the output impedance is comparable to the impedance characteristic as in the case with SE846 with dip in the 5k which causes an EQ like drop of -2dB in that impedance dip(shown below) when matched with AK240 of 3.24ohm output impedance.
 

 

[bigshot]

  My girlfirrend is considering getting an Iphone 5s or an Ipod Touch 5G. I would like to ask a few questions...
1) Is there any noticable difference between the two in means of sound alone?

 
None. All Apple products are audibly transparent. They don't have a sound. They present the music as it is. You need to make sure your headphones work with it well though, or you might need an amp.

 

[SilverEars]

   
None. All Apple products are audibly transparent. They don't have a sound. They present the music as it is. You need to make sure your headphones work with it well though, or you might need an amp.

Not exactly.  Some earlier ipods had bass rolloff also.  Ken Rockwells graph of iphone is only resistive load or high impedance ultrasone 8.  Predictively flat since resistors or high impedance output are approximately flat.  No surprise there.

 

[bigshot]

I have the second generation iPod. No bass rolloff. Flat as a pancake. All of my Apple products are audibility transparent, going all the way back to the Mac 8500AV. Line out is what counts. Impedance depends on the headphones, not the iPod.

 

[meurglys0]

  Not exactly.  Some earlier ipods had bass rolloff also.  Ken Rockwells graph of iphone is only resistive load or high impedance ultrasone 8.  Predictively flat since resistors or high impedance output are approximately flat.  No surprise there.

 
 

  I have the second generation iPod. No bass rolloff. Flat as a pancake. All of my Apple products are audibility transparent, going all the way back to the Mac 8500AV. Line out is what counts. Impedance depends on the headphones, not the iPod.

 
Thanks for the answers. She's considering getting portable headphones (cans), so what is the impedance value that the cans should have at minimum and maximum so that she will not need an amp to use it with Iphone 5s (and the same question for Ipod touch, also) ?   

 

[elfary]

yuriv's graphs depicting the iPhone 5s clipping behaviour have been really useful. Thanks a bunch from Spain.

 

[mdelaney1986]

Near perfection at any rate.  To me spending money on outboard DAC's is pretty silly.  There isn't a bit of difference in sound quality between one DAC and another.  Hearing bias will work against your wallet to be sure.   Spend your money on transducers (speakers, headphones etc.)