If you are only going to do playback (no DSP, convolution, etc), then you don't need much power - or RAM, for that matter. Especially if you use Win Server in core mode.
To me the most important thing is to avoid all posible RFI/EMI sources. Wi-fi within the PC, monitor, HDD, fan are all such sources. A small computer sitting by your DAC without a monitor, and controlled from an iPad or such is what I would recommend from a sound point of view. My PC is connected thru LAN to a wi-fi bridge, so all that electrical noise stays outside the computer.
Take a look at the CAPS servers over at computer audiophile website. I don't remember the names, but the least powerful machines would do, I think.
Mine is powerful but because I do DSP and plan to do digital crossovers, etc in there too.
I hope this helps |
Thanks for all of the inputs. before I have had my laptop near my DAC PS audio Direct Stream on the audio rack, I now change the set up for convenience by having the laptop on a small stand right next to my chair. With that, I use a 25ft usb cable to connect laptop to dac. For this current set up, I have an option of buying/building a small form factor PC. It is a little bit cheaper and more powerful than laptop but I am not sure that Do I need all of that power on PC? or another option is to install window server on a PC instead of win7. I never try win server before so I really do not know it is better than win 7. |
Back to the OP question. You can get a lot of views over at computer audiophile forum. I suggest staying with the operating system you are most comfortable with. I never tried a Mini, so can't compare the sound to a Windows machine. I've evolved within Windows machines, though, so I can comment on my experience with that.
My system used to be a Win 7 laptop with JRiver connected to an Audiophilleo with PurePower, connected to a Metrum Octave, tube pre and amp. Music library inside a USB hard drive, which is not ideal. Sound was as good as my Rotel RCD1080 CD player, and I sold the CD player.
Then I built an audio server based on Intel server motherboard (no bells and whistles), Xeon CPU, SSD for JRiver and Win Server 2012. Music on a HDD inside the PC. Fanless case, headless (meaning no monitor and video turned off within the PC). Big jump in audio quality, using same Audiophilleo and Metrum. I also had/have a linear power supply.
Next I added a Paul Pang USB card. Another improvement in sound.
Next I added AudioPhil's Audio Optimizer, which is a software that optimizes Windows setup. Huge improvement in sound. Totally unexpected!
Then I turned Windows Server to core mode. Another significant jump in sound quality. Then I added 3M RFI absorbing paper inside the PC, for another improvement.
The Audiophilleo is of course an asynch USB converter, and a very good one. This experience tells me there are definitely improvements to be had by focusing on the computer itself. Some are software based and can be done on laptops and desktops alike. Most hardware tweaks can be done on desktops only. |
Whatever it is, I just find USB has no place in hi fi. |
There is nothing else. If noise floor is low and the jitter is low then it is only matter of quality of the D/A converter and analog output section which is independent of the type of the DAC. It might be possibly lack of jitter since people are used to some noise or distortion and completely without them it sounds analytic, sterile, not engaging. It is pretty much like a difference between clean Jazz guitar and distorted guitar, Distorted always sounds livelier. |
Its not just jitter. Tough to explain but very easy to listen for. You will just not get the easy going emotion from the sound youre suposed to get. USB is the worse interface you can use. Add a few grand in USB to spidf converters, cables, reclockers and you still have those crappy packets. |
It should be "common mode chokes" - my spellchecker plays
games with me. |
Yes, you might find some USB port noise sensitivity in some DACs: http://archimago.blogspot.com/2015/05/measurements-usb-hubs-and-8khz-phy.html..and he finds one DAC in certain setting producing artifacts of noisy USB HUB but the same time he states that he had never seen this before: Okay, to end off... Let me remind everyone one more time that what I'm measuring with the 8kHz noise here is because of the Emotiva XSP-1's sensitivity to noise through the "Home Theater Bypass" input. The 8kHz tone is NOT something I have ever heard / measured coming out of a reputable DAC's analogue outputs! Nor is it something that's found in Stereophile USB DAC measurements. If it were not for this noise sensitivity, I would not even have bothered with looking at ways to attenuate the computer USB noise. Nonetheless, I think this is an interesting real-life demonstration of the noise pollution that can come out of the computer's USB port and a solution that works reasonably well. I did not bother with jitter tests this time as I have never seen the Dunn J-Test change in any substantial fashion with the use of a hub with an asynchronous DAC (see the measurements last time). Think you have a jitter issue? Save up the cash and buy a better asynchronous USB DAC - forget cables and tweak products IMO. Last sentence is exactly what I'm saying. Also look at Stereophile test of, for instance, Ayre QB-9 especially jitter test (Fig. 14). http://www.stereophile.com/content/ayre-acoustics-qb-9-usb-dac-measurements#rgvqgdT0kSAdPz8x.97It shows no effect of jitter down to -125dB and the only visible jitter artifacts below that are from 120Hz switching noise of linear power supply (120Hz spaced sidebands). This could be fixed by using high quality SMPS. DacMagic behaved poorly in this test. Coupled noise is usually a common mode that can be effectively defeated by even such simple devices like comment mode chokes. You can optimize your system running USB thru quiet Hub (faster computer will make it worse) but the proper thing to do is to find better DAC. |
Kijanki,
Do some research on packet noise and you will see that reclocking is not the perfect answer. It helps if the clock is really stable but that can vary even in real expensive dacs. The Uptone Audio Regen is a device design to reduce packet noise which is generated by the dac reclocking
Alan |
I'm not sure what is the "Packet Noise" and what
it has to do with the quality of the computer (faster
computers tend to create more of electrical noise).
Computer sends frame of data to DAC every millisecond
increasing or decreasing number of samples per frame upon
signal coming from the DAC when amount of data in the buffer
is below or above certain value (over/under flow control).
This data from the computer goes to buffer on digital side
of the DAC. Buffered data goes to A/D converter and is
clocked at internal DAC clock that is COMPLETELY independent
from the computer and the whole transfer operation. This
clock should be well isolated from the system noise and if
it isn't and becomes jittery then buy another DAC, because
this one is poorly executed. |
Arh is spot on. Packets KILL the audio sound. USB was created to connect peripherials. Now, the interface is used to keep customer service costs down as no one needs to open up their computers ever again. I am a student that if is easy, it can't be the absolute best (or at least, let me try something harder to see if it is BETTER). That USB is like a belly button - every puter has one (or a hand full). Me - I'm unique. |
Asynchronous USB sounds like it should solve all the problems but it really doesn't. The reclocking inside a dac creates packet noise which creates jitter which can effect the sound. My Metrum Hex is asynchronous but the choice of the source computer still made a major difference in the quality of sound.
Alan |
Asynchronous USB DAC and network streaming (WiFi, Ethernet) have one thing in common - they change "music" to "data" by removing timing. When timing is recreated on the other side of the bridge (or inside USB DAC) computer's speed, amount of RAM etc. become irrelevant (saving money). |
Mac Mini with asynch USB DAC is the least challenging solution to get right for computer audio. PC's require a EE degree to get past all the things they do intrinsically wrong out of the box. |
I do a lot of streaming over WiFi with Tidal and Classicsonline. When I had a Lenova PC running Windows 8.1 I had nothing but trouble. Constant dropouts, stoppages and sometines I could not even login. I then bought a MacBook Pro running Yosemite and everything works perfectly. I am now sold on Mac
Alan |
Ive researched this a lot and I love JRiver software. If that does not appeal to you then advice from here on may not be accurate for your need.
With JRiver you can run Mac, Windows or Linux and get the same sound, as long as the computer is a modern design with speedy chip set and good RAM.
Im accustomed to Mac since most of my life Ive been a photographer but today a Win machine does the same good Photoshop work and can work as a great music server.
I choose Mac Mini due to size, i7 chip and maximum ram and instruct JRiver to convert all files to 2X DSD. Works so well it frequently surprises me. |
