# STUPID QUESTION BUT What does a DAC do???



## cifani090

What does a DAC do. Doesn't is make you music sound better through iTunes. But how does it work if you have you headphones in your headphone amp, what is there a cable that goes from your DAC to your headphone amp????


----------



## logwed

A DAC (Digital to Analogue Converter) does exactly what the name suggests; turns the digital bits from a digital source material (hard drive/CD/other medium) and converts that information into an analogue electronic signal that our speakers/headphones can use to produce sound. The chain is:
   
  Transport --> DAC --> Amplifier --> Headphones/speakers
   
  A higher quality DAC will do a better job of converting those digital bits into the signal, with a more accurate reproduction of the original sound.


----------



## 9pintube

[size=small]A DAC is a (DIGITAL TO ANALOG CONVERTER),so any piece of equipment that reads a disc must  have a DAC ether built in or use an external DAC to convert the digital signal into an analog signal........I'm sure you'll get all the details about DACs in your post,  I myself try to stick to the information that is "IN THE GROOVES" of my vinyl.....Sorry for basically repeating your words,*logwed* on DACs but,  I had to reboot the page to reply, new sight is still SLOOOOOWER to "ACT" then before.......[/size]


----------



## anwaypasible

a DAC is a tone-generator of the 'reading' type.. while a synthesizer is also a compiler of the 'mouth wide open' or 'input' type.
   
  basically a DAC is like a grand piano.
  picture the information sent in a binary format.
  each 0 and 1 off of the page of data = a tone
   
  and that means each page can have more than one piano key pressed at the same time which makes a different tone when compared to a single key of the piano being pressed.
   
  you should have some respect for the technology considering that each dac has a different 'tune' based on the same principle of the strings on a piano.
  each string must be tightened or loosened to create the pre-determined tone.
  and then again, each string must hold that tone for a long time (some strings will stretch quickly which changes the sound - while others wont)
   
  being specific - each 'string' needs to reproduce the pre-determined tone PERFECTLY.
  but in the DAC world.. the number of 'strings' that create a perfect tone vary.
  another thing to consider is how long will the DAC create the perfect tone.. with age will the tone vary or fluctuate?
   
  how well does the DAC create tones while it is excessively hot.
  how bout excessively cold?
   
  how fast can the DAC create the tone after it has received the information or 'read' the music.
   
  how many 'piano keys' can be pressed at once?
   
  which 'piano key' echoes and refuses to go away?
   
  which 'piano key' requires you to press hard on the key for an audible response?
   
  these are laymans terms and should really help you to appreciate the difference in quality when selecting a DAC.
   
  they all have different values and characteristics because of the materials used and/or because of the price category they are in.


----------



## Phelonious Ponk

Quote: 





anwaypasible said:


> a DAC is a tone-generator of the 'reading' type.. while a synthesizer is also a compiler of the 'mouth wide open' or 'input' type.
> 
> basically a DAC is like a grand piano.
> picture the information sent in a binary format.
> ...


 

 A lovely analogy, but confusing, because a DAC, in and of itself, should have no tone, no characteristic sound. A DAC converts digital data - zeros and ones, on or off - to an analog of your music. Period. Without getting into the esoteric considerations of jitter, which is mostly irrelevant in competent, modern DACs, this basic function is either right or wrong, There is no tone, no ambiguity. Errors in translating the data will be obvious and will sound nothing like the subtle tonal differences between analog components. If you have a problem, you'll know. Which brings us to the output section of a DAC. Like every source component ever made, a DAC must have a stage that amplifies the analog signal up to line level (an easy task requiring very little current, making dedicated power supplies and elaborate preamp designs questionable, at least). Your cd player, iPod, old cassette deck...everything, really, all have such a stage. Some manufacturers choose to use this output stage to color the tone of the DAC. Not a good idea IMO, but it _is_ just an opinion. If you like sources colored, enjoy. Others choose to do the best they can to put out a transparent, uncolored signal. A better idea, IMO.
   
  With the exception of NOS (non over sampling) DACs and a few other odd, antiquated and dubious approaches, its about that simple. The analog stage, is, by the way, the reason why you would have a free-standing DAC instead of just using the one in your CDP or computer. Isolating that analog stage from the electronics inside the source component (particularly a computer) increases the odds of that signal being very quiet, which has a positive effect on revealing detail and dynamics.
   
  P


----------



## PhoneLover94

Quote: 





phelonious ponk said:


> With the exception of NOS (non over sampling) DACs and a few other odd, antiquated and dubious approaches, its about that simple.


 

 Yeah. It is just that simple.....


----------



## Currawong

To answer the OP's question, rather than get into unnecessary arguments about digital conversion *AHEM*....
   
  Everything _before_ the DAC is digital (zeros and ones). Everything _after_ is analogue (waveforms).  So the cable(s) between a DAC and an amp are interconnects carrying a "line level" analogue signal.   It's possible to put both in one box.  However, a headphone amp is designed to better handle the rapid movements of the diaphragm in the headphones, just as a speaker amp does much the same thing.
   
  The analogue output of a DAC is electrically optimised to feed another component. The output of an amp is electrically optimised to handle headphones or speakers as required.  The requirements are different.


----------



## anwaypasible

a proper judgement will tell you.. coloring an inferior dac that has a 'colored' yet 'dynamic' sound can result in a linear final output.
   
  the only question thereafter is, how long will the components keep their specifications before growing old or 'aging' and becoming colored themselves.
   
  but the same can be asked of premium DACS that have no 'colored' sound and are also 'dynamic' in detail.. will they continue to sound good for years and years to come?
   
  maybe a slightly colored DAC that has an array of components on the circuit board to specifically compensate for that coloring of the sound - maybe this choice is the best option considering cost and quality rendered a decade from purchase.
   
  i'd like to think compensating for a colored DAC requires more work than simply selecting a premium DAC off the shelf and giving it's output amplification.
   
  although, i dont like my post being misconstrude one bit.
  maybe reading at a kindergarden level is not something you are capable of.. and to each their own.

  
  Quote: 





phelonious ponk said:


> Some manufacturers choose to use this output stage to color the tone of the DAC. Not a good idea IMO, but it _is_ just an opinion. If you like sources colored, enjoy. Others choose to do the best they can to put out a transparent, uncolored signal. A better idea, IMO.


----------



## reiserFS

A DAC is pretty much self explanatory: it exactly does what the short term stands for, converting a digital input into analog output (headphones, RCA out to amp).


----------



## anwaypasible

this is a prime example of why one headphone amp is far superior than another amp.

  
  Quote: 





currawong said:


> It's possible to put both in one box.  However, a headphone amp is designed to better handle the rapid movements of the diaphragm in the headphones, just as a speaker amp does much the same thing.


----------



## anwaypasible

i forgot one....
   
  how fast can the DAC create numerous different tones after it has read the information?
   
  the faster the more 'rich' and 'realistic' the sound will be.
   
  how many tones can be created all at once (and instantly after reading the information) is really the absolute beautiful difference with DACs.
  once you get into the premium line of DACs.. the options listed in the above sentence is what you will be selecting from.
   
  just like speakers from the 60's and 70's
  they are capable of playing tones FAST
   
  and now.. todays speakers can play tones FAST and also play more than one tone at once.
   
  (well actually.. the 60's and 70's saw speakers that could play more than one tone at once.. and today the speakers are doing dozens and dozens of tones at once)


----------



## ccbass

Mind you that a DAC is not creating tones, but rather electricity, or the analog signal.  The DAC then sends that voltage to the amp and the amp amplifies that signal by so much.
   
  Digital to Analog......
   
  Binary [1's and 0's] to Electrical power
   
   
  Mind you the amp typically has a large input impedance, like 10k ohms, so the output power of the DAC is irrelevant.


----------



## anwaypasible

well, true.
  if you turn your home theater receiver 75% of the way up and grab the bare wires that go to your speaker.. you are gonna get shocked and zapped by electricity and not a 'tone'
   
  and it is the exact same thing with DACs.. they dont produce a 'tone' like a speaker does.
  it is electricity like grabbing the speaker wires as i said.
  
   
  another good point to mention is the input impedance remark.
  a solid reason why one headphone amp is better than another is because of the input impedance (also known as resistance)
   
  if there was little resistance, the electricity from the DAC would be free to flow on to the next step (much like water in at the panama canal where they raise and lower boats) .
  if the water was free to move to the next step or 'layer' the whole process would be perceived as faster or 'quicker'
   
  so in laymans terms once again.. there are specifications that are not revealed to the general public to help them make a choice.
  
  Quote: 





ccbass said:


> Mind you that a DAC is not creating tones, but rather electricity, or the analog signal.  The DAC then sends that voltage to the amp and the amp amplifies that signal by so much.
> 
> Digital to Analog......
> 
> ...


----------



## krmathis

DAC is short for *D*igital to *A*nalog *C*onvertor.
  The name alone should give you a hint about what it does..


----------



## RayleighSilvers

Quote: 





phelonious ponk said:


> A lovely analogy, but confusing, because a DAC, in and of itself, should have no tone, no characteristic sound. A DAC converts digital data - zeros and ones, on or off - to an analog of your music. Period. Without getting into the esoteric considerations of jitter, which is mostly irrelevant in competent, modern DACs, this basic function is either right or wrong, There is no tone, no ambiguity. Errors in translating the data will be obvious and will sound nothing like the subtle tonal differences between analog components. If you have a problem, you'll know. Which brings us to the output section of a DAC. Like every source component ever made, a DAC must have a stage that amplifies the analog signal up to line level (an easy task requiring very little current, making dedicated power supplies and elaborate preamp designs questionable, at least). Your cd player, iPod, old cassette deck...everything, really, all have such a stage. Some manufacturers choose to use this output stage to color the tone of the DAC. Not a good idea IMO, but it _is_ just an opinion. If you like sources colored, enjoy. Others choose to do the best they can to put out a transparent, uncolored signal. A better idea, IMO.
> 
> With the exception of NOS (non over sampling) DACs and a few other odd, antiquated and dubious approaches, its about that simple. The analog stage, is, by the way, the reason why you would have a free-standing DAC instead of just using the one in your CDP or computer. Isolating that analog stage from the electronics inside the source component (particularly a computer) increases the odds of that signal being very quiet, which has a positive effect on revealing detail and dynamics.
> 
> P


 
   
  This post was extremely informative. My understanding of this post is that all DAC's should be the same then? if they aren't converting the 1's and 0's into the correct analogue signal then the music would sound completely different? Does that mean the Cheap DAC's should cost the same as the expensive DAC's? Also what do you mean by quiet? Is this to stop sensitive headphones from hissing or hearing an electrical noise? When I connect my e10's to the line out of the PC mobo, I get electrical noise. Even when I connect the speakers to the mobo line out and then my e10's to the line out of the speaker, but the noise isn't as loud. Does this have anything to do with this topic?


----------



## Timestretch

I would say that DACs to tend to sound the same. The differences in audio quality come along with all of the other components inside the box with the DAC -- power transformers, circuitry, capacitors, specific arrangement of parts, the analog output stage, etc. The DAC chips themselves by this point are pretty spot on. It's the stuff they fit in with that makes most of the difference.  
    
  That said, does anyone have any reference for machine-measurements of the outputs of different dac chips? Just because we can't blind test a difference between chips doesn't mean there isn't a fraction of a percent difference in THD or whatever among them.
   
  And about the noise you're experiencing -- interference, power, ground loops, etc. A lot of electricity moving around in side a computer, creates a lot of interference. this gives you a louder noise floor when you use sensitive headphones to listen for it. Perhaps by hooking the speakers in first, and then the headphones into them, you are adding resistance or something that is muting out that noisefloor a little more? I'm no electrician so someone who knows the exact reasons for this would need to chime in.
  
  Quote: 





rayleighsilvers said:


> This post was extremely informative. My understanding of this post is that all DAC's should be the same then? if they aren't converting the 1's and 0's into the correct analogue signal then the music would sound completely different? Does that mean the Cheap DAC's should cost the same as the expensive DAC's? Also what do you mean by quiet? Is this to stop sensitive headphones from hissing or hearing an electrical noise? When I connect my e10's to the line out of the PC mobo, I get electrical noise. Even when I connect the speakers to the mobo line out and then my e10's to the line out of the speaker, but the noise isn't as loud. Does this have anything to do with this topic?


----------



## RayleighSilvers

I am an electrician (well a trainee anyway 
	

	
	
		
		

		
			





) but we don't really cover microelectronics as much.


----------



## Timestretch

I'm just an office man, so to me, an electrician is basically an electric magician.
  Quote: 





rayleighsilvers said:


> I am an electrician (well a trainee anyway
> 
> 
> 
> ...


----------



## onlyjoekin

I know what a DAC does, but I don't understand this-
People connect DACs after computers in their chain, but surely the signal is already in analogue from the built-in DAC? Does this mean stand alone DACs just improve the analogue signal or does the computer somehow cleverly detect it's there and not bother with it's own d-a conversion? I'm confused. And sorry to add this to an old thread, but ya know, better then starting a new one isn't it? 

Joe


----------



## skamp

Your operating system has configuration facilities to tell your PC what DAC to use, the onboard one or the external one. So your external DAC is indeed only getting digital data, not analog data. The onboard DAC doesn't get used at all.


----------



## onlyjoekin

Ah, thanks for getting bak to me. You don't happen to know how to configure the DAC settings on mac OS X?


----------



## skamp

I don't know about Mac OS X, sorry.


----------



## onlyjoekin

Thanks a lot anyway!


----------



## wberghofer

onlyjoekin said:


> You don't happen to know how to configure the DAC settings on mac OS X?


 
   
  There’s nothing DAC specific which needs to be configured in Mac OS X. Just connect your DAC via USB or optical SPDIF (Toslink), visit System Preferences > Sound, choose the connection and you’re done. It might be useful to run Utilities > Audio MIDI Setup and check the sampling rate and bit depth for the selected audio output device. For standard CD audio playback the options should be set to 44100 Hertz and 2ch-16 bit Integer.
   
  Werner.


----------



## onlyjoekin

Ah, thank you for this. I'm in danger of hijacking this thread, but what does the 'bit integer' mean? 'bits' are data aren't they, so does it mean how long the gap is between each bit sent? If you don't ask, you don't learn!
   
   
  Joe


----------



## skamp

Look it up on Wikipedia: Pulse Code Modulation, bit depth, sampling rate.


----------



## onlyjoekin

Thanks again, I did try looking it up before posting but didn't really know what keywords to use. Makes for some technical reading!


----------



## 438518

hi! i still cant understand! is it a music player? why do an amp need a DAC? i dont understand, ... if i connect an Headphone amp to my Laptop, who is the DAC does a PC have it, why an amp require a DAC when it is conected to 3.5 mm jack headphone output and amplifying in the other side, and the sound is perfect.


----------



## ProtegeManiac

Quote:


> Originally Posted by *Ujka Pjetracaj* /img/forum/go_quote.gif
> hi! i still cant understand! is it a music player? why do an amp need a DAC? i dont understand, ... if i connect an Headphone amp to my Laptop, who is the DAC does a PC have it, why an amp require a DAC when it is conected to 3.5 mm jack headphone output and amplifying in the other side, and the sound is perfect. 
 
The laptop has a DAC but audiophile bull aside what you really need a separate DAC for isn't for the different DAC chip in it specifically but for the circuit after it. Once the signal leaves the DAC chip or the DA section of an integrated chip the analogue signal can take on noise or distortion depending on how it's handled. A separate DAC unit designed to output a fixed 2v output (which is Sony Redbook standard for CDPs) at the very least will take the guesswork out of what level to set anything, since that one is at a fixed level already, so all you have to worry about is your amplifier's volume and gain settings. By comparison your laptop's headphone output was designed to drive a headphone, and it may be too strong a signal for the amplifier, or have a lot of noise and maybe distortion that the amplifier can pick up and make even more audible, plus in older operating systems (not sure if it's still true in newer OS) the digital volume control can lower the bit depth (you'll go below 16bits). A dedicated DAC will take all the guesswork out of figuring out the best setting in terms of noise without affecting the bit depth
 
That said there are a couple of things to note here. There _are_ DACs that output more than 2volts, best guess is that especially when it's not a lot over 2volts, it can have a significant edge in a subjective comparison. At the same time there are cases where the DAC's output stage can make a significant difference depending on how they implement the analogue stage, not necessarily as distortion per se (although that isn't out of the question, like how some deliberately color it with tubes) but sometimes the filter for the inaudible frequencies may affect the audible range differently.


----------



## 438518

im far away to understand it, thank you anyway.


----------



## HesAlwaysNearUs

I have same "genius question". ATM im looking for headphone dac. For example there is dac's with 24bit / 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz , 192kHz and 32 bit / 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz , 192kHz, 352.8kHz,384kHz. How does this works? Dac recognizes any incoming signal between those scales from PC and converts to analog? Or recognizes and first converts to max (for example 32 bit 384khz) and only then sends to analog? I dont get this.
 What if i listen only qobuz and that has only 16 bit/ 44.1 khz format?
 What means those descriptions on dac's specifications and how they works?
 Should i look to 24 bit or 32 bit dac?


----------



## 444042

hi! i just wanted to tell you my experience with the Fiio e17 2.
 ....i returned it back:
 the Audio Quality is fine. it supports 24bit and it is build in AMP.
 to be honest i did not heared the difference betwen my Sony Vaio, VPCF13M0E output jack. and my ex. Fiio e17
 as it belongs to the audio quality, "i mean that kind of quality that old Stereos did once upon a time."
 the audio is clear but there is something missing, is not just about to be clear. is the information you get.
 i mean they did the song more beautifull. "sorry i dont speak well english and i dont know how to explain, i hope you understand."
is like  ... when you go a note up in a Piano. there is a more lovely note. because of the middle voice is hight and clearer.
  
  
  e17 as it Belongs to the AMP. it has a very powerfull AMP. but why do i need that in my ears, as long as i use ATHM50X
 these can be powered without an AMP. anyway, it boosts the Bass but i dont need to much Bass on my Ear.
 i like the Bass. But not im my ear. as it hurts and damage my ears. "i really was interested in the DAC and Not the AMP."
 so i returned it back to Amazon from where it was coming.
 if you want to power some high immpedance Headphones it can be good.
 as it Belongs to the DAC It may beat any Computer Sound Card, but not mine as it supports 24 bit output too.
  
 i recomend you go find some old "like 2003" stereo system that supports optical or digital  input. like my Philips LX3700D "it supports digital only"
 and you will get the best sound. "Decorated Sound"
 i promise you.


----------



## HesAlwaysNearUs

hesalwaysnearus said:


> I have same "genius question". ATM im looking for headphone dac. For example there is dac's with 24bit / 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz , 192kHz and 32 bit / 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz , 192kHz, 352.8kHz,384kHz. How does this works? Dac recognizes any incoming signal between those scales from PC and converts to analog? Or recognizes and first converts to max (for example 32 bit 384khz) and only then sends to analog? I dont get this.
> What if i listen only qobuz and that has only 16 bit/ 44.1 khz format?
> What means those descriptions on dac's specifications and how they works?
> Should i look to 24 bit or 32 bit dac?


 
 I find out that these are parameters for up or down scalling. Thank you


----------



## akshaysalkar

Is it like a DAC should be seperated from a AMP ? 
  
  
 And also .. are these DACs for headphones or for Speakers ?


----------



## ProtegeManiac

hesalwaysnearus said:


> I have same "genius question". ATM im looking for headphone dac. For example there is dac's with 24bit / 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz , 192kHz and 32 bit / 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz , 192kHz, 352.8kHz,384kHz. How does this works? Dac recognizes any incoming signal between those scales from PC and converts to analog? Or recognizes and first converts to max (for example 32 bit 384khz) and only then sends to analog? I dont get this.
> What if i listen only qobuz and that has only 16 bit/ 44.1 khz format?
> What means those descriptions on dac's specifications and how they works?
> Should i look to 24 bit or 32 bit dac?


 

 ​If the DAC has an oversampling or upsampling function then it can modify the signal, usually done by a specialized DSP chip (sometimes it's the USB or SPDIF receiver chip). For the most part though unless it is specified as such the receiver chip takes the signal as it is and just converts it to analogue without modifying the digital signal.
 
Note that you're more likely to find up/oversampling chips on more conventional gear, likely due to how popular non-OS DACs were on top of the exposure of how changes in the sound through such a digital reprocessing was noise rather than actual extension of the treble that it was able to recover.


----------



## Nintendam

ProtegeManiac said:


> If the DAC has an oversampling or upsampling function then it can modify the signal, usually done by a specialized DSP chip (sometimes it's the USB or SPDIF receiver chip). For the most part though unless it is specified as such the receiver chip takes the signal as it is and just converts it to analogue without modifying the digital signal.
> 
> Note that you're more likely to find up/oversampling chips on more conventional gear, likely due to how popular non-OS DACs were on top of the exposure of how changes in the sound through such a digital reprocessing was noise rather than actual extension of the treble that it was able to recover.
Apologies reviving this thread from the dead, have had my first week with a DAC/amp combo (q1mkii with a balanced cable and 6XX)

My first impressions are floored, I know this thread is old but do you see the mkii as oversampled or over colored? The bass boost most certainly adds some color but gives it a nice bite.

Perhaps I am just confirming the benefit of a good dedicated DAC, with enough amplification to power something like the hd650's (hd6XX).

For example, I was showing the 6xx's off a year ago when I got em and people just 'liked' them. Could see the potential. But recently with the mkii, balanced cable, etc, everyone was completely blown away, it took them to a level they haven't heard before in a phone.

As an entry DAC/amp, it's great, but now I'm not sure if I can stop!


----------



## ProtegeManiac

Nintendam said:


> Apologies reviving this thread from the dead, have had my first week with a DAC/amp combo (q1mkii with a balanced cable and 6XX)
> 
> *My first impressions are floored, I know this thread is old but do you see the mkii as oversampled or over colored? The bass boost most certainly adds some color but gives it a nice bite.*
> 
> ...



Only tried it briefly but not with my HD600; i used a Grado, which given the low impedance is more likely to get colored if the amp has high output impedance. That's not really a problem there, but depending on the distortion pattern, some battery powered gear will get distortion trying to drive them (like my old CMOY, which sounds normal with the SR225 and SR80, but absolutely dark at the treble and gutless in the low end with the HD600). I wouldn't guess the Q1 MkII will have that problem though as I haven't seen any review of anything that severe about what it sounds like.

As for the bass boost, I never really use those unless I'm listening to something like Lil Jon or Late Night Alumni.


----------

