Getting lineout signal from dac in computer directly to headphone amp, bypassing amps in computer?
Jul 25, 2008 at 8:35 AM Thread Starter Post #1 of 14

vYu223

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Man, all of this is so confusing.

How do I get a "true" line out from my computer?

I mean, you know how when you connect the lineout from an ipod (via lineout dock) to a headphone amp, the volume control in the ipod does not affect the volume of the signal exiting the lineout dock?

How do I do that for my computer (windows xp)? I mean, how do I get the signal from the DAC (which is in my computer) directly to my headphone amplifier so that any volume controls in the computer (like kmixer) will not affect the volume of the signal going to my headphone amp? Sorry if I sound like an idiot; I'm new in the whole computer audio thing.

Or do I have to go all digital, meaning usb dac or spdif?

Thanks, everyone!
 
Jul 25, 2008 at 2:33 PM Post #2 of 14
I use a Lineout cable from iPod via XMOD to Headphones.

sounds terrible.

iPod to me sounds better without the DAC...or maybe the lineout cable quality also matters?


Guys.. where to get that iMod cable which bypass iPods 3.5mm jack/? any brands?
 
Jul 25, 2008 at 2:33 PM Post #3 of 14
What you're concerned about is XP's K-Mixer, which resamples audio to 48khz when using XP's volume or balance control sliders. This is done in the digital domain prior to any analogue output from your soundcard; the same happens also if you're using a USB-S/PDIF digital transport device.

To avoid this resampling, you don't have to go "all digital" (i.e. use an external DAC).

If your device supports ASIO, you can use ASIO in Winamp or Foobar audio players, along with ASIO drivers for your audio device, or ASIO4ALL (a free driver). Foobar's "kernel streaming" is another option.

http://www.aqvox.de/Asio-USB-Audio-installation-e.htm <- this guide is a bit out of date, and is written assuming a USB device, but it can apply to any ASIO capable soundcard, too.

Search the forum or the net for guides on ASIO installation if you need more info.
 
Jul 25, 2008 at 4:18 PM Post #4 of 14
The outputs on a sound card are mainly meant for powered speakers with volume knobs. Don't confuse the fact that you can use DSPs on your computer, including volume control, with the volume knob on an amp. It would be nice (if only for durability reasons) if more soundcards had RCA or 1/4" left and right outputs, but space is very limited on the back of a PCI slot and people want mic input, digital in/out, and various surround sound options stuffed in there.
 
Jul 25, 2008 at 6:44 PM Post #5 of 14
A DAC/Amp combo is doing the job of a soundcard.

The DAC wants the most basic audio signal around, ideally it'd just directly suck audio files stored on your HDD.

The output of a DAC is a perfect 'line-out', which is at fixed volume and needs to go in an Amplifier.

This method is essentially making your computer a fancy transport, just storage of raw data, the fancy bit being your media-player.



So, in answer to your query, it is bypassing most things computer. ASIO cleans up a few things[XPs meddling].
 
Jul 25, 2008 at 9:00 PM Post #6 of 14
Is it still possible to do ASIO on a sound card that does not natively support ASIO? Or do I need to get a new soundcard that does?
 
Jul 25, 2008 at 9:52 PM Post #7 of 14
Quote:

Originally Posted by vYu223 /img/forum/go_quote.gif
Is it still possible to do ASIO on a sound card that does not natively support ASIO? Or do I need to get a new soundcard that does?


Certainly is, use a separate ASIO driver like ASIO4ALL, a free universal ASIO driver for Windows that brings ASIO support to users of virtually all consumer-grade soundcards.

There is a set-up guide on here, search for it.
biggrin.gif
 
Jul 25, 2008 at 10:05 PM Post #8 of 14
ASIO4ALL works even with the most ghetto onboard audio chipsets.
 
Jul 25, 2008 at 10:20 PM Post #9 of 14
I'd like to ask everybody a similar related question if I could. I'm using an external DAC and amp to power both a speaker and headphone setup. In this setup I want the PC to act solely as a transport with as little interference as possible. To that end I'm using a digital line-out from the soundcard (an HT Omega Claro+ if that matters), and ASIO with winamp to keep windows out of the signal path as much as possible. The problem is that the volume controls, including the windows master volume and those of the soundcard, still affet the level of the line output. This in and of itself isn't such a big deal one would think, except that where this level is set has a clear impact on sound quality. As the volume level is raised the audio begins to sound heavy and compressed, as if all dynamic range is being lost. At it's extreme it becomes a mess with an ugly resonance smearing all sonic details. The lower I set the volume in windows the more this subsides, but even setting the volume very low does not eliminate it.

If I use an external CD player to drive my DAC the sound is amazing, up to very loud levels with none of the problems I describe above. I'm very confused because the signal in question is digital. Even if the volume control is doing something it's a digital signal and should not be impacting the audio quality. I'm not sure what else to do since ASIO did not address it (on the contrary, the increased clarity brought the problem into the limelight). Could it be a problem specific to my soundcard perhaps? I'm completely lost here and would greatly appreciate any help. I love the convenience of having my whole music library on the PC and have spent a lot of money putting these audio components together. I don't want to have to "give up" and go back to jockeying cds in and out of a bulky player.
 
Jul 26, 2008 at 2:52 AM Post #10 of 14
So! I've finally got Foobar2000 and ASIO4ALL and followed this guide:

http://www.head-fi.org/forums/f46/as...nation-221237/

I've finished the guide, and now the lowest of the bass and the highest of the treble are finally actually audible! Sound quality has improved in all aspects.

However, there is just one thing. Microsoft's volume control in the tray, in the lower right corner of my screen (kmixer?) still affects the volume! Have I done something wrong? Or is this the way it's supposed to be?
 
Jul 27, 2008 at 2:43 PM Post #11 of 14
But i heard ASIO4ALL doesnt work on Vista? and doesnt affect SQ much?

any Vista guy wanna shed some light?
 
Jul 27, 2008 at 2:50 PM Post #12 of 14
Vista doesn't use Kmixer, so ASIO is not needed.
 
Jul 28, 2008 at 8:23 AM Post #13 of 14
Quote:

Originally Posted by Chri5peed /img/forum/go_quote.gif
Vista doesn't use Kmixer, so ASIO is not needed.


But if you have a native asio card use it,it works fine.
RME Digi still thumping away on Vista.
Nothing like a good analogue output.


Ford2.
 
Aug 9, 2008 at 7:37 AM Post #14 of 14
Assuming you have a X-Fi (with headpones running out of the front L/R 3.5mm analog out), Vista SP1 and a 2 channel 16/44.1 source (like wav or flac):

1. Set Vista to 2 channel 16/44.1

2. Set X-Fi to Audio Creation and bit-perfect playback

3. Get Foobar and the new WASAPI plugin. Set preferences to 16/44.1

This is what I did and it seems to work, but yeah...the Windows volume control still functions =/

If you have a DAC that accepts digital coax or optical in, then you might set the X-Fi to 16/44.1 digital out as well and see if that disables the Windows volume control (seems to me I have read that it does indeed disable volume controls).
 

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