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What is a DAC?

post #1 of 20
Thread Starter 
OK this is quite noobish. but what is a DAC? I am pretty new to amps but not new to music. Can someone please explain athe DAC and amp how they work together and what all they do.
post #2 of 20
A dac is a digital to analog converter... and, well, it converts digital signals (via coaxial or optical cables) to analog signals, which go into the amp.
post #3 of 20
Right, well, I'll get smeared by engineers, but . . .

CDs store information in digital bits, on or off, 1 or 0. Lots of 1s and 0s together form words of sorts. The DAC translates the digital words into analog signals, which the amplifier then makes "louder", strong enough to drive speakers.

By far most amplifiers can only amplify analog signals. Therefore CD players incorporate DACs to translate the digital signals from the CD into an analog output.

I guess there are now digital amplifiers, but I know even less about those than about analog amplifiers.

A CD transport is what spins a CD and reads the digital information stored on the CD. A DAC is what translates the digital signal into an analog signal. And a CD player combines the transport and the DAC into a single chassis.

Hope that helps!
post #4 of 20
Thread Starter 
OK so in the pic thread is that a DAC that thier DAP is pluged into and then into the amp? If that is the case wouldn't this be redundient?
post #5 of 20
It has the source, to a dac to the amp.

I use a Monica II dac that I built up and modified. It takes an optical in for the digital signal. The Monica II is in a Altoids tin and is run by 6 AA batteries for a run time of around 12 hours or a little more. I have a dac I built at home that uses Audio Note nickel double C core output transformers and it gives this fantastic dac a run for its money. So you can have reference sound on the road and for me it makes listening all the more enjoyable when just listening to the music and not the nasties of something poor in the musical chain.
post #6 of 20
Quote:
Originally Posted by chef8489
OK so in the pic thread is that a DAC that thier DAP is pluged into and then into the amp? If that is the case wouldn't this be redundient?
In quantity, yes; in quality, no. When you run a cable from your source to an amp without a DAC in the middle, you are using the source's incorporated DAC (like when you connect RCA interconnects from your cd player to your amp or a mini cable from your DAP to your portable amp). When you add a separate DAC, you take the digital signal as it is from the transport and transform it into an analog signal that a normal amp can read. It is the same thing, just higher quality. Think of it as adding an amp to your system. Every DAP out there has an amp integrated that can power your headphones. When you add a separate amp, it is the same thing just higher quality.

Hope it helps.
post #7 of 20
Ok, this can all get confusing if you don't understand exactly what the functions of all of these pieces are. The easier way to think of it is from an economics perspective.

Your iPod costs $250 and performs 3 basic functions.
1. Read music from the hard drive (Transport)
2. Convert that digital bitstream to a analog wave. (DAC)
3. Sends that analog signal out to your headphones. (Amp)

I can guarantee you that about 75% of the cost of your iPod is going into function 1. Functions 2 and 3 are more of an afterthought.

The HeadRoom MicroDAC costs $250 by itself and performs exactly one function. Logic would dictate that it is going to do a better job than the simple DAC built into the iPod.

So, everytime you dedicate a single piece of equipment to a particular function, the better each piece is going to be at its one job. You've heard the phrase "Jack of all trades, master of none". The iPod is a Jack-of-all-trades but the dedicated DAC is a master of its one function.
post #8 of 20
aragorn18 said:

Quote:
The HeadRoom MicroDAC costs $250 by itself and performs exactly one function. Logic would dictate that it is going to do a better job than the simple DAC built into the iPod
Does the inclusion of a DAC between the MP3 player and the Headphone amp, make a substantial sound improvement or are we talking slight improvements in the sound that only an experienced audiophile would detect.
post #9 of 20
Quote:
Originally Posted by j24
Does the inclusion of a DAC between the MP3 player and the Headphone amp, make a substantial sound improvement or are we talking slight improvements in the sound that only an experienced audiophile would detect.
Well I can't tell you what difference it would make and how much a difference you can tell but (as far as I know) there's only really the iRiver H1xx series that has a digital output that can feed a DAC and those can only really be had now via auction sites like eBay as they stopped making them a long time ago.

Personally my x5l doesn't have a digital out (or even a decent line out! ) but I can only hope that some company makes a decent DAP with a nice digital out - then us audiophiles can be happy.
post #10 of 20
Quote:
Originally Posted by j24
Does the inclusion of a DAC between the MP3 player and the Headphone amp, make a substantial sound improvement or are we talking slight improvements in the sound that only an experienced audiophile would detect.
Unfortunately, that's not an answer I can really give you. That's the whole goal of building your own audio system. Some people will listen to one component and not hear any bit of difference, and someone else will hear a major difference. It's incredibly subjective.

A lot of the improvement will come from replacing parts that are particularly bad in the original piece. If your computer has a really bad sound card, then an external USB DAC will make a bigger difference than someone who is upgrading from an audiophile-grade sound card.

The end result is that Your Mileage May Vary (YMMV).

As was already mentioned though, you're going to have a hard time finding a portable player with digital output to even make use of the external DAC.
post #11 of 20
Thread revive...
Does a DAC output a line-level signal? Does doing source->DAC->headphones result in hearing almost nothing?
post #12 of 20
^Yes
post #13 of 20
Many separate DACs on the market also include a headphone amplifier. Benchmark DAC1, Grace 902, Lavry DA11, Audio-gd Compass, etc..

edit: answered wrong question
post #14 of 20

Delete


Edited by labrat - 9/15/11 at 4:50am
post #15 of 20
A DAC will make appreciable changes in the sound. Many people consider the source to be the most important component.
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