Feeding External DAC via Laptop's USB port

[ascherjim]

This query is one I initially posted in the nether regions of another thread but it apparently went unnoticed and was thus unanswered, hence this new thread. My query is clearly so basic and fundamental that I'm embarrassed to have to ask it. Will flac-converted music I have on my laptop's hard drive be accessible as a digital feed from my laptop's usb port to an external dac with its own usb input port, fed by any of the music player programs on my laptop?

 

[boozcool]

Yes, that is basically the method I'm using now. However, to achieve the best possible sound, use ASIO4ALL to bypass any processing which could be done by your computer
Depending on your DAC, it might be useful to invest in a USB audio converter such as the Trends UD-10.1 or USB Thingee to convert the digital signal from USB into optical or coax to feed the DAC.
Hope this helps!

 

[ascherjim]

Quote:

Originally Posted by boozcool /img/forum/go_quote.gif Yes, that is basically the method I'm using now. However, to achieve the best possible sound, use ASIO4ALL to bypass any processing which could be done by your computer's sound card. Depending on your DAC, it might be useful to invest in a USB audio converter such as the Trends UD-10.1 or USB Thingee to convert the digital signal from USB into optical or coax to feed the DAC. Hope this helps!

Many thanks for you quick and useful response. The Trends converter looks really interesting, and I would probably consider acquiring it -- if the system I am concerned with were in fact my primary system. However, my primary system is Squeezebox oriented, with the Squeezebox feeding into my Headroom DAC via coaxial cable then into a Bottlehead tube amp.

What I am thinking of, and hence my query, is for traveling purposes with my laptop, but without my Squeezebox and tube amp, but instead with a portable USB DAC and a portable headphone amplifier. On this basis, the Trend converter would be just too much extra equipment to carry around. I might just as well take my Squeezebox with me, in that case

No, I think I just want to feed my portable DAC directly from the laptop. Will my on-board music players work? I notice you recommend ASIO4ALL, which I do not yet have installed on my laptop and which I'm, perhaps irrationally, a bit leery of having to monkey with. I've not had a successful experience in the past in dealing with ASIO.

Anyway, any other suggestions you might have would be welcomed.

 

[obobskivich]

first of all, the internal soundcard is not bypassed, it simply isn't used, and ASIO4all won't benefit you in that regard (quite frankly, boozcool is wrong), the data never touches the internal equipment

at least in context of a USB streaming audio device, which the OP is talking about

also, to quote fallenangel, when will people get rid of this notion of a USB DAC

 

[S J]

Quote:

Originally Posted by obobskivich /img/forum/go_quote.gif also, to quote fallenangel, when will people get rid of this notion of a USB DAC

Whats wrong with USB DACs?

 

[obobskivich]

Quote:

Originally Posted by S J /img/forum/go_quote.gif Whats wrong with USB DACs?

they don't exist?

the point is that a DAC is a DAC is a DAC, they can accept different types of inputs for different standards, some handle audio, some handle video, some handle seismology, some handle weigh scales, and they take all different types of inputs, to look at consumer audio D/A's, you've got USB -> S/PDIF, direct S/PDIF, I2S, and AES (on higher end equipment), but its not like USB DACs are their own subset or unique device, its just a cheap USB to S/PDIF streaming chipset and then a S/PDIF to analog codec or D/A

but the joy of head-fi has created a belief that a "USB DAC" is defined as a device which plugs into a USB port, and produces an amplified headphone output, which then leads to questions like this, and others, wondering about bypassing internal cards, and "well with a DAC I can drive better headphones"

its basically the ignorance of it, because people refuse to read or learn anything substantial, and instead just wanna live in marketing fairy world, which I suspect is a lot like the land of care-a lot, you've got a bunch of multi-colour bears running around spreading joy and rainbows while don cheadle stands there saying "we can all live in harmony" and michael jackson singing "we are the world" in the background

aside from all of that, nothing is explicitly wrong with it

 

[boozcool]

So your saying the internal sound card is never used for all USB streaming audio? Does this mean that it makes no difference whether I use Direct Sound, Kernal, or ASIO to bypass Windows Kmixer?

 

[obobskivich]

Quote:

Originally Posted by boozcool /img/forum/go_quote.gif So your saying the internal sound card is never used for all USB streaming audio? Does this mean that it makes no difference whether I use Direct Sound, Kernal, or ASIO to bypass Windows Kmixer?

you're confusing two things here

the software layer will ALWAYS be used with audio, however the device its communicating with and handling changes, so with USB streaming audio, you've got Kmixer, or Direct Sound, or Core Audio, or whatever else, communicating with the USB streaming audio drivers, which are in turn talking to the USB -> S/PDIF hardware, which in turn gives you S/PDIF to analog (its all done in one IC anymore)

while with the internal soundcard, you're simply doing the same, but with the internal soundcard, not the USB device

so if you're using the USB device, all of the software still exists, its just not using some of the hardware

if my explanation doesn't make 100% complete sense feel free to ask me to clarify (i'm half awake, and honestly probably couldn't read what I just wrote and make 100% complete sense of it)

 

[ascherjim]

While this discussion is certainly interesting, unless I'm more dense than usual my basic question has not yet been answered. Let me rephrase it. How can I get a music feed from my laptop's USB port of flac music on my hard drive?

 

[linuxworks]

flac is irrelevant. its an encoding that expands 'just the same' as wav files.

the usb part you are asking about is a usb to spdif converter. get one. this is what I use:

Newegg.com - Turtle Beach Audio Advantage Micro Virtual 5.1 Surround Channels USB Interface Sound Card - Sound Cards

from there, you go via opto to some dac. I assume you can take it from there?

 

[ascherjim]

Linuxworks: This is possibly a solution. Would I still need this item if my DAC already has a USB input port? Thanks. Jim

 

[TopPop]

Quote:

Originally Posted by obobskivich /img/forum/go_quote.gif they don't exist? the point is that a DAC is a DAC is a DAC, they can accept different types of inputs for different standards, some handle audio, some handle video, some handle seismology, some handle weigh scales, and they take all different types of inputs, to look at consumer audio D/A's, you've got USB -> S/PDIF, direct S/PDIF, I2S, and AES (on higher end equipment), but its not like USB DACs are their own subset or unique device, its just a cheap USB to S/PDIF streaming chipset and then a S/PDIF to analog codec or D/A but the joy of head-fi has created a belief that a "USB DAC" is defined as a device which plugs into a USB port, and produces an amplified headphone output, which then leads to questions like this, and others, wondering about bypassing internal cards, and "well with a DAC I can drive better headphones" its basically the ignorance of it, because people refuse to read or learn anything substantial, and instead just wanna live in marketing fairy world, which I suspect is a lot like the land of care-a lot, you've got a bunch of multi-colour bears running around spreading joy and rainbows while don cheadle stands there saying "we can all live in harmony" and michael jackson singing "we are the world" in the background aside from all of that, nothing is explicitly wrong with it

I don't get it... a DAC, that uses USB as a digital input... a USB DAC, right?

Am I missing something here? What else would you prefer that we simpletons call it?

 

[boozcool]

I see
I thought that the software layer is implemented by the sound card, but, correct me if I'm wrong, it is actually the computer itself handling the software layer

 

[linuxworks]

Quote:

Originally Posted by boozcool /img/forum/go_quote.gif I see I thought that the software layer is implemented by the sound card, but, correct me if I'm wrong, it is actually the computer itself handling the software layer

software layer implemented by hardware? you have that sort of backwards.

there are software layers, firmware layers, hardware layers and even in that, there are boundaries you can draw for other functional sub-blocks.

in the end, each implementation varies. some use more hardware 'assist' and others (old ac97) does not.

it really depends. blanket statements are not as useful here.

 

[linuxworks]

Quote:

Originally Posted by ascherjim /img/forum/go_quote.gif Linuxworks: This is possibly a solution. Would I still need this item if my DAC already has a USB input port? Thanks. Jim

if your *current* dac has usb, fine, use it. but will your next dac have it?

every dac except those odd 'usb only' dacs have spdif.

to me, that's the 'rca interconnect' (so to speak!) of digital audio. everything 'that matters' should be able to speak spdif. its the least common denom and so its a good one to 'bet' on.

you may even find - maybe - that feeding spdif to your dac is better than its internal usb/spdif or usb/i2s conversion. you just have to try both. perhaps they will both sound the same. you have to try to know.