Importance of DAC

O&B HCA300 Power Amplifier
I dont agree. Its definitely not day and night difference. I wont believe even if guru says it, unless its proven ;)

Any speaker and amp(even high end) has much bad measurement numbers. So DAC is definitely not the only one to blame.

Shorter the chain the better. IMO people add too many components into the chain to make them sound better and hence they add too many variables and then perceive something better than other.

I think I am correct, copied from NwAvGuy: Headphone Amps/DACs Explained -

iPOD DACs: I think most of these are a waste of money as most modern iPods already have very respectable DACs in them. For example, the iPod Touch 3Gs DAC outperforms the one in the popular NuForce uDAC-2. I havent tested all the latest iPods, but in general, their DACs already approach the point of diminishing returns. So its rather difficult to significantly improve on them. See my Sansa Clip+ review for some iPod tests. And an external DAC can make jitter worse because to get the signal to the external DAC the critical digital audio clock (the very source of jitter in the first place) has to be embedded along with the audio data and then extracted at the other end. This introduces a new, and potentially significant, source of jitter thats not present with the internal I2S interface inside the iPod. To be brutally honest, most external iPod DACs are just manufactures looking to make more money off the iPod audiophile revolution not products that make sense.

PC DAC? If your source is a PC or Mac, should you use an outboard DAC? It depends. If your PC is your main music source and you have a very high quality speakers (which excludes 95% of desktop PC speakers) and/or headphones in the $200+ category, then yes you might want to consider an outboard DACespecially if you can hear any audible flaws when using the one in your PC. But a lot of PCs have respectable DACs in them. If the problem is your headphones not getting loud enough, just an amp may be enough. Even something inexpensive like the $20 FiiO E5 might do the trick.​

Thanks Thad for the the site! Its a treasure of knowledge!
 
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theredcommando said:
I have also earlier posted very similar measurements and link for Thad's Motorola DEFY mobile phone.

Motorola DEFY review: Drag and drop - GSMArena.com

As one can see, numbers are not very bad(its not poor at all!) for mobile either. Stereo crosstalk, dynamic range seems better in custom DAC(but I am not very sure if unit of measurement is same in both cases).
Dedicated MP3 players might even excel these readings.

I think people percieve difference in audio quality not because of DAC but because of amp and speaker as both these components add their own color to the final output.
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I think people perceive differences not only because of the factors that you mention, which are true, but also because every DAC has an analogue side, and that circuitry is as capable of adding colour, or performing better/worse according to any of the technical audio measurements, as any amplifier.

Consider a DAC as being a source. On a turntable, the cartridge is the point at which physical shapes in a groove become sound: a DAC is the place where digital information becomes sound. In this light, it could be argued that the DAC is the most important component of all!

On the acoustic performance of my Defy+, I can only say one thing, and it something that fellow members might be surprised to hear me say: I can only believe my ears! But it is not inconsistent with other arguments that I have made, because I have always said that, when auditioning or buying, that is what all of us do, but that the industry and on- or off-line publications should back up their assertions with measurements (not manufacturer-provided specs) and with blind testing. Of course, some of the publications do publish measurements, but there is still, when it comes to comparative testing, a major denial of blind testing.

I should have said, and will add now, that my Defy+ was just a quick test ---but then, it was quick partly because I found it fatiguing. I don't know how to define this "fatigue" effect: perhaps someone can suggest the right technical terms. It felt like I was listening to low-bit-rate MP3s, whereas I was listening to FLACs. I was also listening to a symphony which has rather a gentle beginning: I had to pump the volume up. Had I listened to the whole piece, I know I would have had to lower it again later.

When we say "DAC" we are speaking of more than the chip that does the essential conversion. We have to include the whole box, with its power supply and analogue circuitry between the chip and the output sockets. When we speak of the DAC on a portable device, unless that device has a dedicated line-out, we have no alternative but to include the built-in headphone amplifier too, as we have no other way to listen. Is it even fair to include such devices when talking of DACs?

Thanks for the GSMArena link and tests: I'll be taking a good look at that.
 
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I have a somewhat limited understanding, but I will try to see if I can point out somethings about a good dac which separates it from a poor dac.

First of all, the quality of source will not be reflected with equipment which dont possess the resolution to bring out all the details the source is giving out.

Difference between a blu-ray and a dvd wont be as evident on a 19 inch crt as it will be on a 42 inch 1080p plasma or even a 32 inch 1080p lcd.

Please dont take it in any other sense, but what other equipment you use in the chain will very much determine the level of sound quality you will be able to see in a dac.

Frequency response is just one side of the picture.

Lets take another thing into the factor - imaging, which can be considered as the spatial location of instruments by which you can identify the source of each musical instrument and their location in the overall music. It is primarily determined by two qualities of the playback system: channel separation and phase information in the musical signal. And it all begins with the dac.

A good channel separation will ensure that the way the recording engineer separated the music into the different into the left and right channels, maintaining the individuality of the different sound sources is maintained when the analog signal is decoded from the digital signal and sent over to the amplification system (recording is done in good studios using microphone arrays, where a separate channel for each sound source arrives at the mixing desk and the mixing engineer mixes them in to stereo channels, maintaining different levels for the same source in the two channels to give the impression of lateral location). In this way when the same signal reaches you at the same time but at different level from the two channels, you get an impression of lateral spatiality.. ie different sound sources seem to be located in a horizontal plane, separated from each other. But to resolve this level of detail the channel separation and level detail for each signal has to be maintained all across the chain, preamp to power amp to speakers for it to reach the listener the way it is intended.

Maintaining phase information is essential to separate the multitude of different signals that is there in a music signal. There are different instruments playing at different time delays at different frequencies and they are all sent across in a signal with complex harmonics and phase shifted signal patterns. Inability of maintaining this will totally screw up the musical signal and wont allow the rest of the system to resolve the intricate details of the music which were there in the digital signal but were not resolved by the dac.

As the dac takes a digital signal and converts it into an analog electrical pulse, it needs a power source to generate the music signal. This is most crucial since good clean power is essential in the entire signal chain as ultimately the music is an electrical signal. In run of the mill dacs the power section is skimped the most with improper voltage regulation, lack of RF filtration and in general noisy power supplies. This raises the noise floor of the system from the source, making the noise a part of the signal itself. Some one said that preamps, power amps and speakers have their own noise filtration. I dont know about speaker, but I think preamps and power amps have their noise filtration for removing their own power supply noise, but when the noise is a part of the signal itself, they cant do anything but to pass it on. There is a reason the high end dacs use big toroidal transformers and large filter and bypass caps to feed the power into the dac. Then again, the rest of the system needs to be able to show what is noise and what is music when given a good source.

And last but most important, if the source digital file being converted by the dac does not have the details itself, like low bitrate mp3s, then the dac has nothing to do add what is not already there. But if the information is there, then an average dac wont be able to pass it over the to the amp and speakers to play it to us.

A long post made possible by a bad day at office. Please correct my mistakes.

Edit: Of course, my mentioning of what happens in a studio is very much simplified, as there are lots of other things in mixing. But I just wanted to convey the basic idea of what I understood.
 
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Yes ipods used to have great DAC chips from wolfson in them especially the 4th generation ones. But you were talking of your phone whole specs are no match to a Dac costing 5 to 10K. Secondly if you want to hear differences on a creative PC audio system you are unlikely to hear them. So for the majority of people who do not have quality speakers and amps upgrading a DAC is not logical.

However since audiophiles start with speakers followed by amplifiers and have tons of uncompressed music the DAC surely matters. You can go a meet some in your locality and hear there systems. One can percieve every musical instrument in three dimension in front of you. I can even hear the expiration of singers on various vocal tracks.
 
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@theredcommando I see you are in Pune. I would love to host you and show the difference a simple (200$ or less) DAC can make against a very reputed onboard codec based solution.

The difference "is" day and night.

Whether one is capable of hearing it or not is a matter of subjective assessment. However technically, the DAC onboard most PCs is fed with a very noisy powerline shared by ever other component on the motherboard. The amplification is "not an option" so if some board provides a headphone out and not "line out" you have to live with the sadly colored output and the list goes on.
 
Instead of going through the charts why dont you try an audition of any good dac or a cd player and compare the output with your mobile or whatever media player you have (assuming except the dac/mobile, everything in the chain is same).
The audition should be done with atleast one more person than you. Also post the listening impressions, just curious to know... Make sure that you audition using the songs which you are really aware of.
 
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^ that would be best thing to do IMHO.
Then if there is a difference, we can figure out why.
Personally, I realised the difference when the laptop a long while back when I was using my Cowon D2 and my laptops onboard sound with my Onkyo avr and Mission speakers and then on one occasion i took the same laptop and used it with another forum members audio set up which had Marantz Pm17 and a fantastic pair of Scanspeak based diy speakers. We tried 3 sources: marantz cd6003, keces dac and onboard sound from my hp laptop. The same source I was listening to at my place without issues paled in comparison to the other two! It sounded dry, dull, lifeless, thin! The Keces dac when used with the laptop improved things. But still it just failed to match the Marantz Cd6002 that our host was using in his set up. The CDP scored better on all counts, soundstage, tonality, dynamics, imaging etc
 
Last weekend, I put together a diy amp and to test it the only source I had at hand was my phone (Samsung Note). The sound was anaemic and the bass was bloated. My first reaction was to check if the wires somewhere were reversed and I was hearing the two speakers out of phase as it sounded as though there were things missing from the song.

Next day, I used my laptop (Macbook Air) as a source and the amp was not sounding broken anymore.

I think the difference I heard between using the two sources was more due to the analog section of the two devices and perhaps less the quality of the DA section. But, the difference even between my phone and my laptop was day and night.

I ordered an ODAC and an O2 amp kit 10 days ago from , should be reaching me on Monday, waiting eagerly to put it together for my headphone rig.
 
Aaaah.. now we are reaching some consensus.

@Audiodoc
My phone output is not that bad, at least going by measurements. Dynamic range, Frequency response and Noise level is better than Ipod5G.

@ruenigma
Thanks! I am obliged... I would definitely love to. Will PM you...

@cmsajith
Yes. Problem with that approach is, even if I am convinced that there IS difference I would not be knowing the reason. And as it is turning out, there is not much objective difference between the two(I hope you agree on that). Main motive of this thread was to find out some output param that differs hugely between the two. NwAvGuy has some pointed out, though.

Now about the subjective difference.
Its difficult to comment. I dont like subjective readings that much. Bose is successful... Do you care? Everybody's ear(even mindset, room) is different too.

Even if amp and speaker is same and you change the source, those are going to adulterate the signal. Their output is not ideal either(Genelec is the only exception, and such good characteristics are not possible with external amp, so external amp is no-no too). Only ultra high end have excellent output characteristics comparable to DAC response.

@Surrealistic @iaudio
These comments are important. But they inherently assume that amp, speaker and listener are ideal which is difficult to be true...

Here is PSB alpha 1 measurements which are far from ideal-
SoundStage! Measurements - PSB Alpha B1 Loudspeakers (10/2006)
Compared to these, onboard DAC output seems much more cleaner...

Giving s listen seems to be the way out. What suits you is more important than anything else. Genelec 1031A is excellent, YOU may feel its bass-heavy/bright/dull/analytical etc. But it remains the fact that its excellent. You might even think that some other speaker sounds better than it, but then it would be your opinion, not fact. If your ear does not hear some range properly, you might want to boost it. But speaker is not at fault
 
@surrealistic
For how much did you order the DAC and headphone amplifier. Can you please post the link.

Thanks in advance.
 
@surrealistic and other who have ordered the ODAC, would love to know your opinion about the DAC once you have heard it.
 
@Audiodoc
After following the given links, problem is that phone cannot drive the headphone properly. May be this is the difference people are experiencing when they connect without DAC.

They are using DAC as headphone amp and hence the difference.

Any active speaker owners(just headphone out to speaker in) can comment how change of source(onboard{mp3 player/mobile} vs dedicated DAC) affects the quality(make sure that source is proven to be good, like an Ipod)?

Also I totally agree with possible interference by elex components on motherboard and unfiltered power supply on computer(not sure about their impact, though). Descent MP3 player/good mobile would reduce this by great extent.
 
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One should understand the audio section of any phone or media player. Till the signal reaches the DAC chip everything is in the digital domain as 0s and 1s. The DAC chip converts the digital signal in the analog domain. This quality of conversion is dependent on the chip (wolfson, sabre, analog devices, burrbrown, cirrus logic are some well known ones), the power supply to the chip, the clock crystal, quality components, and the way the circuit is designed. These in turn leads to the high parameters of SNR, THD, IMD, stereo cross talk, dynamic range etc.

After the signal are converted into the analog domain they need a separate circuit to drive the headphone. This may be based on a chip or a discrete design and usually should have a second regulated power supply.

When you take the signal from the headphone out of a phone you have to pass through both these stages and both are made of cheap DAC and amplifier chips on a single power supply. Some devices like the ipod / sansa players are different though. One can use a line out from these devices by using certain adapter as available from Fiio (L6 and L7). This was you can bypass the headphone amplifier stage.

On the other hand the DAC chip in the newer ipod has reduced in quality after the 5.5 generation. Previously they used the wolfson DAC chips as used in the FiiO E7 etc however they have shifted to cirrus logic chips now.
 
theredcommando said:
@Audiodoc
After following the given links, problem is that phone cannot drive the headphone properly. May be this is the difference people are experiencing when they connect without DAC.
Click to expand...
As far as I can see, there is no way to get digital audio out of my Defy+. Therefore it is not possible to connect it to a DAC.

Any active speaker owners(just headphone out to speaker in) can comment how change of source(onboard{mp3 player/mobile} vs dedicated DAC) affects the quality(make sure that source is proven to be good, like an Ipod)?
Click to expand...
Not at all clear what you mean by this.

Compare phone/mobile player analogue out to analogue out of DAC ... connected to what? What DAC? Any phone/player? Any DAC?



Also I totally agree with possible interference by elex components on motherboard and unfiltered power supply on computer(not sure about their impact, though). Descent MP3 player/good mobile would reduce this by great extent.
Click to expand...
What has this comparison got to do with the original question.

1. The effect of power supply, RF noise, etc etc, on a properly designed sound card inside a PC is largely theoretical, and, whilst there is no harm in avoiding that theoretical problem by putting the audio interface outside the box, largely exagerated.

2. How is a phone going to provide a cleaner environment. Cell phone frequencies, GPS, all sorts of sensors, all crammed in a tiny space.

For starters, a PC does not have a continual, ongoing conversation with all the cell towers around it.

I think you need to reconsider your goal posts.
 
@ theredcommando

Nothing and NOTHING can substitute theREAL EXPERIENCE.
Numbers tell you the half truth. Check figures of tube amps ,,esp distortion figures ....power ratings ...actually they should not exist ...and again audiophiles swear by it.

again remember GIGO principle - garbage in - garbage out ..so if you fed mp3 to any machine - it will sound crappy . Tell me if you have experience flac on cellphone and then on better media players and then on good system?

yes sometimes your experience does not match common logic. Once mre and my fried tested Glenfiditch 15 Year old and 12 year old back to back and found 12 year old better testing than 15 year old!!! Now that was surprise.. but sometimes personal taste overrides everything!( Like I prefer Haywords 5000 over Corona, Tiger, Asahi etc!)

So get your fav music ripped in flac - and go to some knowledgeable , helpful member home like ruenigma ,,,and experience the dac yourself!

As I say numbers tell half the story ..and you annot put everything in numbers!Like if you say criteria for good actress is 36(++) 24 (-) 36 (+) then Pamela Anderson would be a leading actress right??

BTW - If you feel I am bit high... maybe I as I just finished my 4 th raw peg of Glenlivet ( 12 YO) amen , rock to everyone!
 
I already have a better hybrid DIY amplifier EHHA so not interested in the O2. I also have a all solid state discrete DIY beyerdynamic A1 headphone amplifier.

Booked the ODAC from the second seller jds labs. They are selling without the enclosure for 99 dollars however with enclosure it is costly 149 dollars and it is a preorder. Will make the enclosure from the FiiO E11 packaging.
 
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Even I ordered ODAC (preorder, not sure when it will ship) from JDS Labs. ODAC doesn't have co-axial input. And No Async USB. So it is little bit of a bet as of now, since we don't have many solid reviews.

So to use with CD transport, I need:
Co-axial --> USB.
Of course no such device in market; since most DACs already provide co-axial inputs. And there is no advantage in audio path with this approach.

However, if CD players provide Async USB as transport, it may be quite useful, and methinks it should be a better transport option and make external DACs much more popular.

And how about:
Co-axial --> Async USB ?
Even this should be useful device, isn't it?

vikoma
 
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