[TheJT]

So from my understanding, an amp basically receives an audio signal and is used to adjust output to headphones.  The only reason you'd ever need an amp is if your mp3 player or whatnot can't sufficiently drive your headphones.  A DAC is a source.  It's where the signal originates and you'd buy one to clean up sound quality.  An amp doesn't necessarily come with a DAC.  But a DAC definitely comes with an amp?  Something like a FiiO E10 acts as a DAC and AMP.  Something like a E6 is just an AMP.  If something has DAC capabilities, it's usually called a DAC over an AMP.  
Is there such thing as just a DAC but no AMP?

 

[MattTCG]

Sure there is. 

 

[qohelet]

So from my understanding, an amp basically receives an audio signal and is used to adjust output to headphones.  The only reason you'd ever need an amp is if your mp3 player or whatnot can't sufficiently drive your headphones.  A DAC is a source.  It's where the signal originates and you'd buy one to clean up sound quality.  An amp doesn't necessarily come with a DAC.  But a DAC definitely comes with an amp?  Something like a FiiO E10 acts as a DAC and AMP.  Something like a E6 is just an AMP.  If something has DAC capabilities, it's usually called a DAC over an AMP.  
Is there such thing as just a DAC but no AMP?

Lots of them.

 

[mikeaj]

Quote:

The only reason you'd ever need an amp is if your mp3 player or whatnot can't sufficiently drive your headphones.

 
Not really, particularly without a pretty liberal interpretation "sufficiently drive".  One amp can drive headphones with higher fidelity than another, or otherwise with a different sound quality.  An amp's volume control and jacks positioning could be ergonomically preferably in some setups to use.  Hardware volume control has advantages over software volume control in some situations, since the latter can result in some information being thrown away.  Some amps have auxiliary features like EQ options and crossfeed that some may prefer.
 
 

A DAC is a source.  It's where the signal originates and you'd buy one to clean up sound quality.

 
Depends what you mean by "the signal".  It's where the analog (voltage) signal is generated.  (The digital audio information is transmitted as a signal as well.)  Maybe you know what's going on, but "clean up sound quality" implies a different function than is actually being performed.  It's clearer to say that given the same input, one DAC can produce a cleaner signal than another.  It's not like DACs are processing a dirty signal to improve it.
 
 
As others already mentioned, there exist many audio DACs without integrated headphone amplifiers.  See FiiO D3, HRT Music Streamer II, CEntrance DACPort LX, and so on.

 

[dazedbus]

DAC - Digital to analog converter.  Essentially does exactly what it says.  This converts a digital signal (1s and 0s) that comes from optical, coaxial etc into an analog signal that can be used to play sound waves (superposition of waves).  This is essential and you cannot do without it.  The benefits of having a separate DAC is that it will change the properties (soundstage, imaging, instrument separation, details, reverberation) of the music and in general has high signal to noise (low background noise when on full volume).  For example, if you are using a good amplifier and very good headphones, out of your headphone jack, I'm sure that you will not notice the benefits of having such a headphone.  Similarly if you have a good dac, but bad headphones you won't hear the difference.
 
The typical design goal of amplifiers is to increase the sizes of the waves (which will provide more volume) while not altering the overall signal itself.  However, it is easier said than done and most amplifiers do not completely amplify the entire audio spectrum evenly (bass roll-off) and some have low frequencies filtered and amplified (bass boost).  Also most of the background noise (noise that occurs when no sound is playing) that you hear will probably come from amplifiers.  When people complain that an amplifier does not properly drive a headphone; they probably mean that they cannot get to high enough volumes (current limitation for low impedance, voltage limitation for high impedance), they get distortion which sounds bad at high volumes (or their listening volumes) or that they simply are not getting the frequency response that they would like due to the frequency limitations of the amplifier.

 

[proton007]

 
Quote:

The benefits of having a separate DAC is that it will change the properties (soundstage, imaging, instrument separation, details, reverberation) of the music and in general has high signal to noise (low background noise when on full volume).  For example, if you are using a good amplifier and very good headphones, out of your headphone jack, I'm sure that you will not notice the benefits of having such a headphone.  Similarly if you have a good dac, but bad headphones you won't hear the difference.

 
I agree with the second part, but this one is somewhat hard to state as a fact.
DACs are implemented as off the shelf solutions, and UNLESS the external DAC can reduce signal crossover, the soundstage and separation will not show any improvement. Chances are an external DAC you buy also use the same dac chip (or maybe a step higher) than ones already used in media players, which means a change of < 0.5dB on the THD and frequency response, even if there is any.
Also, it depends on the source you're replacing it with. If with a PC/Laptop with an integrated sound card, then yes. If with a professional/high end sound card, not much. Same goes for media players.
Differences between DACs are so minute you'll need to have pretty special hearing to figure them out. Similarly, 'bad' and 'good' headphones are also pretty subjective.

 

[TheJT]

Thanks for all the responses.
 
Quote:

 
 
I agree with the second part, but this one is somewhat hard to state as a fact.
DACs are implemented as off the shelf solutions, and UNLESS the external DAC can reduce signal crossover, the soundstage and separation will not show any improvement. Chances are an external DAC you buy also use the same dac chip (or maybe a step higher) than ones already used in media players, which means a change of < 0.5dB on the THD and frequency response, even if there is any.
Also, it depends on the source you're replacing it with. If with a PC/Laptop with an integrated sound card, then yes. If with a professional/high end sound card, not much. Same goes for media players.
Differences between DACs are so minute you'll need to have pretty special hearing to figure them out. Similarly, 'bad' and 'good' headphones are also pretty subjective.

 
So I'm using a 1st generation ipod nano.  My computer doesn't even seem to have a soundcard.  It's probably software, aka High Definition Audio Device.  If I were to buy a Fiio E10 which should offer a better DAC and AMP, would I see any drastic improvements?  I have Brainwavz HM5s.
 

 

[proton007]

 
Quote:

Thanks for all the responses.
 
So I'm using a 1st generation ipod nano.  My computer doesn't even seem to have a soundcard.  It's probably software, aka High Definition Audio Device.  If I were to buy a Fiio E10 which should offer a better DAC and AMP, would I see any drastic improvements?  I have Brainwavz HM5s.
 

 
Depends on the high freq response of your speakers/IEMs/Headphones. You might be able to hear some minute hiss/noise on the quiet sections(especially if you turn the volume up).
Secondly what you get out of the jack is not exactly a DAC analog signal (line out); its passed through a Class C/D amplifier.
 
Try out the same song from your pc and iPod with your IEMs to hear if there's any difference. If yes, get an external DAC.
 

 

[TheJT]

 
Quote:

 
 
Depends on the high freq response of your speakers/IEMs/Headphones. You might be able to hear some minute hiss/noise on the quiet sections(especially if you turn the volume up).
Secondly what you get out of the jack is not exactly a DAC analog signal (line out); its passed through a Class C/D amplifier.
 
Try out the same song from your pc and iPod with your IEMs to hear if there's any difference. If yes, get an external DAC.
 

I was under the impression that sound from an E10 would be superior to that of an ipod or my computer.  I feel like I'm reading your response incorrectly but you seem to be saying that the E10 will only bring the sound from my computer up to par with that of my ipod.
 

 

[Papander]

Imo my E10 is about equal to my motherboards integrated audio chipset. The difference between the two is very subtle. If you are expecting some kind of night and day difference you will be disappointed.

 

[Papander]

But hearing in general is so subjective and can be influenced so easily that you might have different results than me.

 

[TheJT]

 
Quote:

Imo my E10 is about equal to my motherboards integrated audio chipset. The difference between the two is very subtle. If you are expecting some kind of night and day difference you will be disappointed.

 
It depends on what headphones you use though.  What headphones did you use for this test?  That you say portrays a minimal difference between the E10 and an integrated chipset.

 

[proton007]

 
Quote:

 
I was under the impression that sound from an E10 would be superior to that of an ipod or my computer.  I feel like I'm reading your response incorrectly but you seem to be saying that the E10 will only bring the sound from my computer up to par with that of my ipod.
 

 
I can't say how the E10 will perform. What I do mean is that the audio from the integrated sound chip is prone to interference because it contains a lot of different solutions on the same chip. Usually its an ADC/DAC/SPDIF combination. If the DAC is indeed bad, there will be some noise when the volume is turned up in quiet parts. Then you're set to gain a lot by using an external DAC.
AFAIK it also depends on your earphones, something like the Westone UMX3 monitors are very sensitive, they'll highlight this more than others. Those with a HF roll off may not.
 

 

[Papander]

 
Quote:

Imo my E10 is about equal to my motherboards integrated audio chipset. The difference between the two is very subtle. If you are expecting some kind of night and day difference you will be disappointed.

 
It depends on what headphones you use though.  What headphones did you use for this test?  That you say portrays a minimal difference between the E10 and an integrated chipset.

AKG K601 and HD205. E10 is slightly warmer sounding and thus doesn't sound as open as my alc888. But like I said the difference is subtle.

 

[TheJT]

Several Questions
Firstly, according to http://mp4nation.net/catalog/brainwavz-hm5-studio-monitor-headphones-p-663.html?zenid=46f80e20eff1532e13d85e0da1f67244, the hm5 has a rated input power of 100mW.  Does this mean 50mW per channel?
 
Secondly, with an amp like the FiiO E10 which outputs 150mW at 32ohms, do we need to use V=IR to assume that it outputs at 75mW at 64ohms? the resistance of the hm5?
 
Thirdly, what does sensitivity mean?  Specifically 105dB at 1mW which makes no sense to me.  105dB would cause hearing loss and this can be achieved with an input of just 1mW???