[chgolatin2]

Sorry for the naive question but I've been reading a lot about DAC's, so I am wondering, what in the hell is so good about DAC's and what exactly does it do?

Again, sorry for the silly question but I would like some info.  Thanks!

[srb]

A DAC is a Digital to Analog Converter.  All digital formats need one to convert the digital information back into analog sound that you can hear.
 
All CD Players and iPods have them built-in and you can listen to the music either from their analog line-out jacks connected to an amplifier, or from their analog headphone jacks using their built-in headphone amplifier.
 
With the prospect of performing this digital to analog conversion better, devices that have a digital output can bypass their internal DAC, and send this digital data to an external DAC component.  This external DAC then sends the converted analog output into an amplifier.
 
All CD Players have a digital output as well as a stereo pair of analog outputs.  The digital output is usually output electrically from a single RCA jack (coaxial or coax connection) or output optically from a special optical jack (also referred to as Toslkink).  Some amplifiers and all Home Theater Receivers have these digital inputs.
 
You can get sound out of an iPod in three ways:
 
1.  Connect a cable to the headphone jack and into an amplifier.  This is the worst case scenario, as you are taking the signal from a built-in headphone amplifier of mediocre quality and sending that already amplified signal into another amplifier.  The volume control on the iPod will affect the signal from the headphone jack.
 
2.  Use the line-out connector accessed from the multi-pin dock connector located on the bottom of the iPod.  The iPod volume control is bypassed and you are outputting an un-amplified line out signal, but still using the iPod's internal DAC.  This will give you a cleaner sound than using the headphone output.
 
3.  Dock the iPod into a dock like the Wadia 170i, which is one of the few docks that can extract the digital signal from an iPod, bypassing the iPod's internal DAC.  This digital signal would be sent from the Wadia dock either into a separate DAC component and then into an amplifier, or into an amplifier with a built-in DAC.
 
In other words, the Wadia 170i dock unit only extracts the digital signal from the iPod.  You would still need a DAC and an amplifier, either separate components or a unit that combines both an amplifier and a DAC.
 
Hope this helps.
 
Steve

[rodge827]

Hello,

I'll do my best to help you out.

DAC is an acronym that stands for Digital to Analog Converter. This is the place were the digital signal (1's and 0's) are converted to an analog signal. There are many types, but for the most part a DAC is either internal or external.

An internal DAC is what is found in all CD players. The transport reads the digital signal and then sends it through a cable to the DAC, all in the same box.

An external DAC is a stand alone piece of gear that receives the digital signal from a stand alone transport via a digital cable. 

What can make a DAC "good" is up to you the audiophile. We all have different budgets and "ideas" as to what good sound is.

My advice is to read as many reviews and threads about the topic and try to listen to as many systems as possible.

Hope this helps,

Chris

 

[JLM]

To a fault, audiophiles (audiofools) love their equipment, the more the better.  So why do it with one component if you can do it with two (plus a connector)?  Why let the designer of your CD player dictate the DAC function?  Why separate pre-amp, phone pre-amp, power amp, and tuner when you could just get a receiver that the designer has matched?  Why not buy active loudspeakers that have power amps selected by the designer built into them?   

Adding a DAC turns a CD player into a CD transport and is a relatively easy way to upgrade a CD player, but there's no point in adding a poor quality DAC to a good quality CD player.  At the same time its a bit pointless to have a great DAC with a crummy CD player.  And of course there is the sonic contributions/degradations of the digital cable (coax or toslink). 

A lot of the recent buzz regarding DACs has to do with computer audio (computers sometimes with convenience/report devices called music servers).  Music ripped from CDs to a HD - Hard Drive (or even a SSD - Solid State Drive).  The big advantages are the computer superior computing power (to "cleanly" read/store/playback) and organizational convenience, but the big disadvantages is the substandard audio card in nearly all computers and the electrically "noisy" computer environment.  So to get better sound, the digital signal is sent directly to a DAC (normally via a USB cable), thus the term "USB DAC".  And current thinking has it that I2S or firewire connectors (for Apple computers) are better sounding options.

[Big Red Machine]

Agree with JLM.  Flavoring the sound the way YOU want it is a nice methodology and may allow you to use a medium quality transport with any level DAC you care to invest in.

[srb]

And current thinking has it that I2S or firewire connectors (for Apple computers) are better sounding options.

Most desktop PCs within the last few years have Firewire ports.  Less common on laptops, but many do have them as well.
 
Steve

[konut]

My .02c, + or - .02c margin of error. Most discussions about DACs on internet fora concentrate on the digital side of the equation. IMHO, this is wrong. The makers of the DAC chips a pretty scrupulous about getting things right. After all these chips, and yes its usually just a single chip, go for pretty cheap, usually under $5.00. So competition is fierce. Any maker of a substandard chip runs the risk of VERY low volume and bankruptcy. So consequently they're all pretty good and getting better all the time. What really separates the men from the boys is what happens on the analog side of the equation. Since analog is so 'last century', it gets short shrift. When considering a DAC find out about these criteria: 1. Are there separate power supplies for the digital and analog sections? What kind of power supplies? 2. What type of analog scheme is used? Is it unamplified right from the chip? Opamp based? Discrete? Class A? Class A/B? Tube? 3. What is the output impedance and voltage? This will determine what kind of preamp or amp will be appropriate.   

[jimdgoulding]

I use a mid price range Sony DVD player for a transport with a stand alone DAC.  Of course, then you need to buy a digital cable.  Those, there are many, can usually be purchased used for not very much.   

[JLM]

Example:  for roughly $700 my Scott Endler modded Behringer DEQ2496 provides EQ and a very nice step up in resolution (detail/imaging) when added to a $170 Oppo DV-970HD (which itself was Stereophile Class C rated).  But I lost the digital volume control from the Oppo (not recommended to be used anyway due to loss of resolution) and had to add a digital cable between the two pieces.