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post #1 of 7
Thread Starter 

I wish to build a setup delivering audio from a single board computer, probably running Linux, to my receiver, a Denon X1000. I don't have a particular board yet, and the choice of audio over HDMI may / may not be available to me. That actually poses a question - if HDMI audio is available, is that preferable ? I'm only talking about stereo audio here, no video, about 99% flacs.


At the moment both audio and video are stored and replayed on a computer running Win7, and feeding the Denon through HDMI (video and audio); that works great, but I think is overkill if all I want to do is play some music. I have the desire to have a smaller machine to do this. A small, low power (7 or 8 watts) computer controlled by a tablet is the goal (though it may seem a bit nonsensical, given the power requirements of the amp). 


I've looked into USB to S/PDIF converters and have been warned against them.  Does this mean that I'm better off converting my files to analogue with an external DAC then feeding the Denon with the analog signal ? I've now looked further for USB2 DACs, found a few 








Are these the type of devices that I should be looking at? The Denon has HDMI, digital coax, optical and RCA analog inputs, no USB. 


There are quite a few of these listed on eBay. Are there certain chips that I should be looking for? I only have a budget of (tops) $US150 for this, hopefully though something a little lower.

post #2 of 7

If you are just looking at some way to connect the audio out from the low power build I would recommend a couple options.  First and easiest is take a look at what motherboard you are going to use many already have a digital or optical out and you can just use that into the Denon.  Other than that yes you would need some sort of a DAC.  What you have on ebay would work other options would be a usb powered DAC such as:


(out of budget ~$250) Audioquest Dragonfly - http://www.audioquest.com/usb_digital_analog_converter/dragonfly-dac

(in budget <$100) Schiit Audio Modi - http://schiit.com/products/modi


I have the dragonfly and love it you would need a 1/8" to rca cable to connect it to the denon and I HIGHLY recommend getting the dragontail usb extender if you do go with it but depending on where you set the pc you might not need it.  I will be getting the Modi for my comp desk as I am looking for something more permanent setup oriented and I can use the dragonfly on the go with computers.  Also, with the modi you would just need an RCA to RCA cable to connect it to the denon.


Hope this helps and gives you a starting place.

Edited by Oklahoma - 11/4/13 at 10:00am
post #3 of 7
Thread Starter 

Thanks for the reply. Just to explain myself a bit better:


I'm not in a situation of having a board that I need to connect to an amp by any means possible. In a slightly larger nutshell, I have a bunch of flacs sitting on a hard drive that I wish to play at best fidelity while using the least amount of resources. 


I don't have a processing board, but this is what I have in mind http://linux-sunxi.org/A20-Cubietruck It already has optical S/PDIF, I2S and some generic headphone out capability. My quest is to find a better audio transport system than that. I may have misinterpreted things but with the number of devices like DACs and USB-S/PDIF converters available I'd assumed that this was the way to do it, that is, that in order to achieve digital output without problems caused by endless reclocking and glitchy power supplies, I was going to have to but some gear. I don't as yet know if I'll have enough control over the I2S output to feed that to a DAC. 


The alternative to that board is another which doesn't even have generic headphone output but which is considerably cheaper, in which case I really will need some external device, and this won't be just a hunt for better sound.


I don't think that the Dragonfly would work on a non Windows system, being a USB soundcard it really will need drivers and Linux isn't mentioned on their website.


Also a question. That Schiit DAC seems to break a couple of rules that I'd gathered from reading stuff here; it's USB1 (not 2, expensive upgrade) and it doesn't have an external power supply. The next model up takes an self admitted 'leap' to DSD. Are they that good that even being USB1 is going to be OK?


I also, still, have a conceptual gap here. With the deprecation of USB-S/PDIF converters, and the current generation of 'direct' DACs (no intermediate steps), the implication is that I'll get an analog signal to feed to the amp. I just need to get that bit straight in my head

post #4 of 7

So you are basically wanting a way to play the files onto the denon, correct?


Then any pc interface that can read the files will work and then it comes down to how to connect that pc to the denon.  If linux can give you control of the spdif out on the first board then just connecting it that way is the simplest and easiest.  If it cannot then you do need something between the pc and the denon.


Spdif out is a digital out and you are just having the denon do the analog conversion then amp the signal for the speakers all in one package by doing it that way.  The spdif in on the denon would receive the same signal whether it came from an onboard digital out or through a usb adapter.  I believe some of the reason people don't recommend the usb-spdif is that you are only taking a digital usb out and converting it to digital spdif out then the denon would do the digital to analog conversion so why change one digital signal to another then do the analog conversion.  Someone else may correct me if I am wrong on that but that is how I see it.


If you use a dac then yes you would be feeding an analog signal into the denon and it would only be an amp at that point because you are doing the conversion outside the denon. 


So it just depends on how you want to do the conversion; have the denon do it or something else.


Looking again I agree the Dragonfly would likely not work as it uses generic windows drivers so it does require drivers.

The Schiit Modi is a usb 2.0 device (had to look at the spec sheet) as it will work as long as the pc supports usb 2.0 audio out.  I believe it is just the Gen 1 usb interface from Schiit and the Bifrost and up is compatible with their Gen 2 interface.

As for no power supply there are many very highly rated dacs that run off usb power so I don't see it as much of an issue the only recommendation people have is that you use a decent quality usb cable to prevent interference from the 5v and ground lines in the cable into the data lines in the cable.


Another recommendation might be the Audioengine D1 - http://audioengineusa.com/Store/Digital-Audio-Converters/D1-24-Bit-DAC


Hope this helps explain some things.

Edited by Oklahoma - 11/5/13 at 9:13am
post #5 of 7
Thread Starter 

Thanks Oklahoma for the reply. That audioengine DAC is just at my price limit so becomes very attractive. 


As I was saying, I'm not just looking for "a" method to feed audio to the receiver, every motherboard out there has some sort of Realtek audio chip, and I've progresses through a couple of Xonar cards. Now I have a different situation with a low power device, but, yes, it still has S/PDIF, and USB. 


It also has I2S; with my limited knowledge, wouldn't that be the perfect signal to feed to a DAC?


To me, the proliferation of USB-S/PDIF converters and of DACs indicates there's a community of people who regard what I'd call 'onboard' audio as being insufficient. My ignorance is obvious, I don't hide that, but I presume people using these (DACs etc) are using a computer for source; I don't know if CD players or tuners have USB ports on them. I'm curious about that; I know there's easier ways to connect a board to a receiver, for example, the board has S/PDIF, that's pretty easy, but it just seems a lot of folk believe there are better ways, demonstrated by the fact that all these devices exist. 


Similarly with the issue of where to convert the signal to analogue; the proliferation of standalone DACs would indicate people want to do that rather than use the DACs in a receiver. 

These are the points I'm most interested in, how this set of circumstances came about; obviously I can't just posit that question and expect someone will write a history for me. 

All I'm doing is trying to make a system that is as good as it can be (within cost). My references to what people do as evidenced by what people talk about indicated a bit of 'me-too' philosophy from me - true, and there because some of these issues - especially the issue of using a DAC instead of sending a digital signal to a receiver. Again, I guess, there I'm asking "why is it so" which of course isn't a question for a forum. 

post #6 of 7

Many times what happens is devices use a basic off the shelf chip to do the audio conversion.  While this works, it makes sound, how good is it working is the question.  This is like trying to compare going to Wallmart and getting an all in one home theater system and wondering why it doesn't sound as good as the one in the theater.  Well the all in one is just using generic parts and the one in the theater is specifically set up to produce that sound.  As you move up in levels of receivers the dacs that are used get better.  Why does that Denon cost 3k and this Sony only costs 250?  The processing is better.


There are some very good pc audio cards out there; they unfortunately usually start around 200 and are not only dedicated to converting the audio but doing audio processing as is required in games and such.  If you are wanting to improve just the audio sound many times adding a DAC into a system will improve it by how much it depends on where you are starting.  Denon makes very nice receivers so the dac in it should be fairly decent.  If you like the sound of what you are getting from the hdmi it would sound the same ran through a digital optical out into the Denon.  By adding a dedicated DAC you are not adding a step in the processing just where the processing is done.




Source - DAC - AMP - Speakers

Computer Optical - Denon - Denon - whatever speakers you have

Computer USB - Schiit Modi - Denon - whatever speakers you have


This is why I said easiest is to just use the Optical out but by using USB you can add a dac that might sound better than the Denon.


I don't know much about I2S so cannot comment on it as to better or not.


You would be correct for the most part that the proliferation of stand alone dacs came from people not wanting to use the dac in a receiver because good enough wasn't good enough for them.  With that you can either add a standalone dac or replace the receiver and it is usually cheaper to replace a dac than a receiver when looking to upgrade.


Lastly, one big difference between the Audioengine and Schiit dacs is that the Schiit only outputs line out and the Audioengine has a variable preamp out with headphone out.  So you could plug headphones directly into the Audioengine where you would have to go through the Denon for headphones with the Schiit.  Also, you could adjust the volume level directly from the Audioengine without having to change the volume on the Denon where as with the Schiit all level changes would have to be done on the Denon.  I don't know what the difference in the chips is but they would also sound a little different due to each using a different chip to do the analog conversion.


A DAC when good enough isn't good enough.

post #7 of 7
Thread Starter 

What I have at the moment is great; an i3 computer feeding the Denon with HDMI and using WASAPI. It's about as clean as it gets. But without actually getting more equipment to listen to I'm just guessing.  Also, I want to replace the computer with something that draws less power. I'll have to wait to get the low power board, then, to find out if I like it as is, but again not having anything to compare to . You've given me some very attractive options, the audioengine DAC wins just on having a headphone amp. I have a set of AudioTechnica ATH-AD700 which I haven't used for a while, but I remember them sounding great, but sounding like they needed an amp. 


Also there's a semblance of a plan: get the Linux board, see what it sounds like using the S/PDIF and HDMI outputs, (f I can get HDMI sound to work), then look at options, starting with that audioengine DAC. 

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