Modern PC DAC vs "Audiophile DAC"

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So I'm a bit confused about a few things. From a lot of sources, including here, Head-Fi, and others, I see people bashing integrated PC audio chips.

And perhaps this is true for some of the latter chips from the Pentium 4 era, but I think...think...that computer audio is much better than it used to be.

There's a lot of talk about external DACs to bypass the internal circuitry for a higher end conversion...But after comparing some of these 'audiophile DACs' to the DACs/codecs that come with your motherboard, I don't understand how the external DACs can really sound that much better.

For example, take the integrated sound card that I have on my motherboard.

VIA Vinyl VT1708/A - VIA Technologies, Inc.

It can play back 24-bit, 192KHz audio with 100 sound:noise.

That is just the specification, but how much better can you get than that? These kind of chips have become mainstream chips since a few years ago.

So why should I buy something like a PCM1793 over using the DAC circuitry provided with my computer?

Thanks.
 
You're focussing on the DAC chips (which to be honest are not hugely different in performance numbers) rather than the environment they are in. PCs are a hostile environment - very high levels of electrical noise owning to high clock rates and SMPSUs with large switching currents. Getting a decent audio signal out of a PC is the real challenge, owing to the noise levels. A decent isolating transformer applied directly at the pins of the DAC chip itself might do it, but they're about as expensive as an external solution.
 
Not everyone notices the difference in sound. So I suggest you find a way to try it yourself and if you do not notice the difference then you've saved yourself money which you can then put towards more software (hi-res downloads don't come cheap).

<edit> I notice a difference between the on-board DAC and a very cheap plug-in soundcard, so buy one of those and listen at home. If you notice the difference then you might be in the market for improved (and more expensive) soundcards.
 
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I would not bother with FLAC if you don't hear the difference between on-motherboard audio and external DAC audio. mp3 vbr (average 160k) doesn't sound half bad on my system, the differences between it and uncompressed are much smaller than the differences I've been talking about. Of course if you aspire to greater things then FLAC is a long term investment. :)
 
Yeah I think source is most important. I don't know where I'm going to find 50 Cent if FLAC though....*cough* torrents >.> What? I didn't say anything.

Huh?

Regarding your original post, the guys that I know that build their own music servers feel that an external DAC is essential to get the best sound.
As abraxalito has mentioned, the inside of your computer is just about the most hostile enviornment you can imagine for music reproduction.

I'd certainly take his advice and try an external DAC, or a different soundcard, to see if the difference is enough to make it worthwhile for you.

Best Regards,
TerryO
 
Yeah the new PCI/PCI-e Asus Xonar cards have EMI protection. It has a big metal shroud over it. Creative also has some cards like that.

I understand that theoretically it should sound worse than external, but I've never heard anything but onboard sound/cheap sound cards, so I can't say that an external DAC won't make a difference. It might help a lot for all I know.

I was just curious because I'm in the middle of amp, headphone amp, speakers, and a sub for my computer right now...that's all going to be in the same box. I was thinking I might try to incorporate a DAC right into the box, but I think I'll wait on it, and see how this sounds first, and then make a judgement.

Thanks.
 
Yeah the new PCI/PCI-e Asus Xonar cards have EMI protection. It has a big metal shroud over it. Creative also has some cards like that.

I have a couple of Asus cards - they're good and I recommend them wholeheartedly but that shroud - its pure marketing. Just makes the card look kinda cool but absolutely no benefit to EMI which is conducted down all the wires, not radiated.
 
Oh really? Hmm...well they fooled me. I just assumed since we like to use metal cases for amps and such, that the shroud would do the same. Ironic that I'm using a wooden case for my amp build. (Don't hurt me!) :p

So if the externals DACs avoid EMI because they are taking pure digital signal (10101010), which can't be affected by EMI, and then converts it in an environment where EMI is not (or less) present?

Makes sense....
 
My impression is that the problem is the shared ground impedance between the DAC on the motherboard and the socket for the audio. That groundplane has all kinds of currents flowing in it and it gets superimposed on the audio.

When you use an external card you have no major RF currents flowing between the DAC ground and the output ground.
 
Hi,

So why should I buy something like a PCM1793 over using the DAC circuitry provided with my computer?

If you have to ask that question, you should not buy something.

Honestly.

Ciao T

PS, my Media PC has the same audio chipset. I use an external USB/SPDIF converter and a seperate DAC.
 
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Just one comment I'd make is that you really want to stay away from the torrents.. :eek: :D

Used CD purchased cheap on eBay and converted to FLAC is both safer, completely legal and importantly you can control the conversion process and make sure you get a good conversion.

EAC is open source, free and last time I checked supported many external codecs including FLAC.
 
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My impression is that the problem is the shared ground impedance between the DAC on the motherboard and the socket for the audio. That groundplane has all kinds of currents flowing in it and it gets superimposed on the audio.

When you use an external card you have no major RF currents flowing between the DAC ground and the output ground.

I'll corroborate that based on messing around with FFT based measurement software even with good internal PCI sound cards as compared to on board audio. (desktop mobo) The difference is even more significant with external dacs.

My laptop is excruciatingly mediocre, spuriae appear only about 65dB down from 0dBFS. It sounds OK through headphones, but is useless for any sort of measurements - this is extreme of course. Laptop is an old Compaq EVO N610C, but its ancient predecessor was roughly 25dB better.. :eek:
 
Oh really? Hmm...well they fooled me. I just assumed since we like to use metal cases for amps and such, that the shroud would do the same. Ironic that I'm using a wooden case for my amp build. (Don't hurt me!) :p

So if the externals DACs avoid EMI because they are taking pure digital signal (10101010), which can't be affected by EMI, and then converts it in an environment where EMI is not (or less) present?

Makes sense....

Law,

You realize that those 1's and 0's are expressed as voltage levels within the circuitry, don't you?
Most computers have very noisy power supplies and the manufactuer's aren't, evidently, very concerned about it either. A few guys that I know, who still burn their own CDs use external burners with a separate, external and highly regulated precision power supply.

Best Regards,
TerryO
 
Yes LOL...I wire doesn't know the difference between a 0 and a 1. But I'm saying: Digital is Digital. You can't really mess up a digital signal too badly. Analog is much more prone to being tampered with but EMI/RFI etc.

I use a Seasonic power supply in my computer....If you know anything about building PCs, Seasonic is pretty much top tier. Not sure about the noise, but I tried my best to get a good PSU.
 
Just one comment I'd make is that you really want to stay away from the torrents.. :eek: :D

Used CD purchased cheap on eBay and converted to FLAC is both safer, completely legal and importantly you can control the conversion process and make sure you get a good conversion.

EAC is open source, free and last time I checked supported many external codecs including FLAC.

Ha. Yeah I have tons of CDs. Most I've bought used from Coconuts/FYE and other places. Most of them were $3-8 each. It can add up, but I also have a friend that just got a notice from the Federal government for downloading Harry Potter off Pirate Bay....so spend a few hundred dollars on CDs or pay a few thousand in fines....hmmm....
 
You're focussing on the DAC chips (which to be honest are not hugely different in performance numbers) rather than the environment they are in. PCs are a hostile environment - very high levels of electrical noise owning to high clock rates and SMPSUs with large switching currents. Getting a decent audio signal out of a PC is the real challenge, owing to the noise levels. A decent isolating transformer applied directly at the pins of the DAC chip itself might do it, but they're about as expensive as an external solution.

Why would you be bothered about switching at MHz and GHz?

Don't say ahh well you can hear a difference...

What do class T switch at?

Some might say a Class T amp is no comparison to awesome class A amps but there are people who say otherwise.

Oh yes audio debates! I forgot.....
 
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