Build An Audiophile Music Server (CA03)

My thoughts exactly Rick. There are some other options, but right now Signal on the iPod Touch is the best bet in my opinion. A little quirky, but certainly good.<br />

<br />

With the release of the Apple iPhone SDK should come a bunch of apps.

I know this isn't the right place to talk about this but. . . with signal can't you surf your library? or do you have to use all playlists? <br />

<br />

Chris,<br />

<br />

Like the new setup. How does this USB DAC rank to the benchmark in your eyes?<br />

<br />

Jim

Hey Jim - CA is laid back as you know, so feel free to discuss anything anywhere :-)<br />

<br />

You are correct, with Signal you can browse you entire library not just playlists.<br />

<br />

The Stello DA100 appears to be a good DAC from what I've read and heard. This unit may be very close to the Benchmark in performance for 16/44.1 music because it is a DAC only and doesn't have any headphone amp or preamp built-in. Not that these are bad things, but there is often something to be said about single purpose devices. There are some other really nice Stello DACs and I am guessing there is some trickle down effect going on here with good technology.

Some of us out in the world don't like Apple products. Any chance you could do a PC (Windows or Linux) version?<br />

<br />

Perhaps something like this (Windows):<br />

<br />

High-end PC:<br />

- AOpen MP945-D (http://minipc.aopen.com/Global/spec_945D.htm) - $280<br />

- 2GB PC4200 SODIMM (2x1GB) - $40<br />

- Celeron 430 (since you don't need much CPU for a music server) - $52<br />

- 160GB WD Scorpio 2.5" SATA HDD - $90<br />

- Windows XP or Windows Vista (OEM) - $100<br />

- Windows Media Player - FREE<br />

<br />

Alternately, if you want to go cheaper:<br />

- D201GLY2 motherboard + CPU ($75)<br />

- mini-ITX case ($80 - $150 depending on what you want)<br />

- 2GB PC4200 DIMM (single stick) - $40<br />

- 160GB WD Scorpio 2.5" SATA HDD - $90<br />

- Windows XP or Windows Vista (OEM) - $100<br />

- Windows Media Player - FREE<br />

<br />

All other components could remain the same.<br />

Thanks for the post Donkeyshins. I'll try to offer an equivalent PC model next time. I've been a little hesitant because I don't like the non-bit perfect issues on PCs. No worries though, I'll get to it.

FWIW - I run a Stello DA100 DAC in combination with a Stello HP100 headphone amp and an X-HiFi speaker system on my desktop at work (where, sadly, I spend most of my time). I have been very happy with the sound quality of the system. I found the following review to be quite informative back when I purchased the DA100. Keep up the good work.<br />

http://www.soundstage.com/revequip/stello_da100.htm<br />

Thanks for the info & link Joe.

You can install FLAC support into Windows Media Player and Media Center (see http://flac.sourceforge.net/documentation_tasks.html for how-to). I've done it and it works well - it allows for bit-perfect copies in Windows. Plus, if you use Vista Home Premium, you can use the built-in Media Center functionality (and a suitable MCE remote) to remotely control your system (provided you have an monitor).

Thanks for the info Donkey.<br />

<br />

I think we should be careful with the use of "bit-perfect."<br />

<br />

flac may produce bit-perfect copies as you noted. But, this should not be interpreted by others to mean bit-perfect output on Windows.

Good point. I was under the (mistaken) assumption that Vista had bit-perfect output, but evidently this is not the case (unless you are using something like XXHighEnd, which is still in beta, supports only .WAV files and costs 72 Euros). My apologies.<br />

<br />

On the other hand, from a purely subjective standpoint, how easy is it to tell bit-perfect from non-bit-perfect output? Personally I have no experience so I can't answer this question, but perhaps you can?<br />

<br />

Thanks!

The difference between the two and all the variables that can effect the sound make this an impossible question to answer. <br />

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Is there a difference between the way a Porsche 911 handles in a traffic jam and the way a Mini Cooper handles in a traffic jam? Probably not because they are both going 5 miles per hour. So, on certain systems there may be no difference in audible quality between bit perfect and not bit perfect. There are also differences between every bit perfect application and every not bit perfect application that are audible. <br />

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I always say if it sounds good to you then it sounds good. No worries.

Ahhh, but you can squeeeeze in the Mini.

<cite>unless you are using something like XXHighEnd, which is still in beta, supports only .WAV files</cite><br />

<br />

plus FLAC and MP3 (and DTS passthrough) at all common sample rates and bit depths.<br />

Why provide wrong information ?<br />

<br />

:-)<br />

Thanks for clearing this up Peter. It must have been a misunderstanding. I'm sure Donkeyshins wasn't trying to spread misinformation.

I have become very much interested in PC based music since buying a new Mac Mini recently.<br />

Your CA music systems all seem to go directly to the DAC from the computer.<br />

Is there a better quality of sound achieved by going directly to the DAC via USB vs. going to the DAC via the optical output from something like the Airport Express with Airtunes?<br />

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My Mini is running my desktop system. I just received my Audioengie2 speakers, and will probably get the KingRex $199 USB DAC. However, I would like to control my living room stereo system from my desktop Mini. <br />

I would probably use something like the Benchmarc DAC1/USB in that system. I'm trying not to have to buy another Mini for the living room system.<br />

<br />

The Squeezebox Duet looks interesting, except that I download my music from ITunes which squeezebox doesn't accept unless you convert the songs to a lesser audio format.<br />

<br />

Barry

Hi Barry welcome to Computer Audiophile. Many people think the sound quality is better when going directly from the computer to the DAC via USB v. using an Airport Express and optical output. I don't know of many people who are fans of TOSlink, but the Benchmark guys are fairly certain there is no difference in sound on their DAC1 using USB or TOSlink. This of course was in a hard wired situation. The AE does ad a very mid-fi quality to the whole equation. It also does not support any 24/96 content.<br />

<br />

I recommend purchasing the new Airport Express for a hundred bucks or so. At this price you can really lose. If you like it then you've saved the cost of a new Mini. <br />

<br />

I'm not a big fan of the Squeezebox products because of the software and limitations.

Hi Chris, <br />

<br />

Thanks for another exciting episode in the series. I have a few questions to help me understand the incremental value between CA02 and CA03, and also also get a handle on music servers in general:<br />

<br />

* What specifically does the DA100 DAC give you over the UD-01? It seems to have lots more features, but is there a sound quality difference, and if so, what contributes to that?<br />

<br />

* Does the MyBook contain 2 separate physical 1TB drives? If so, when you say "The drives also appear as a single external hard drive to you", it seems that for all intents and purposes there is only one drive in use, with the other being exclusively backup. Is that what this means? Obviously I don't have any experience with RAID.<br />

<br />

* Let's say for the moment that I have the goal of having my music server sound as good as my current audio setup. Based on my current understanding, it would seem that I need to get a DAC of the same caliber or better than the one in my current CD player. Am I on track here? To rephrase the question: assuming iTunes bit-perfect output, is the DAC the only part of the digital chain that affects sound quality?<br />

<br />

-Jeff<br />

<br />

<br />

Hi Jeff - <br />

<br />

1. The DA100 DAC v. the UD-01: The difference in the DACs is features as you suggest and "should" be sound quality. I'm a firm believer that everything makes a difference. Every part that makes up a DAC can effect the sound. In addition to hardware there are many software/firmware differences between products. Many manufacturers put their own spin on how they implement DACs such as how they convert USB input once it comes into the unit. Do they convert to I2S or SPDIF etc... I used the word "should" earlier because all of this depends on your playback system. Good or bad may matter just as much as system synergy. A more expensive DAC is not always better and may actually sound terrible under certain circumstances.<br />

<br />

2. The MyBook contains two 1 TB drives. These will appear like one drive. You can set them up how you want. 1 TB of usable space with the remaining 1 TB as a backup is my suggestion (RAID 1). The drives mirror each other automatically. You can also use them in a RAID 0 configuration where both TB are usable. This doubles your chances of failure. Lose one disk and you lose the data on both. <br />

<br />

3. I think the DAC is the most critical piece of the system, but certainly not the only one that effects sound quality. On a Mac you have TOSlink or USB output. Many people think USB is vastly superior to TOSlink. You also have the option to use a device like the Airport Express and transfer your music via wireless through a mid-fi box (AE) and out via TOSlink. There are also external reclockers like the Empirical Audio Pace Car. I would start with a DAC equivalent to your existing CD player if that is how you're leaning. Connect it direct via USB and listen for a while. Many people think the sound is better even though the DACs are equivalent. If you're listening to a NAIM 555 or Audio Research CD7 you'll need to spend some serious money to better their sound, but I believe it is do-able.

4. One more thing I forgot to mention. Application all effect the sound quality. even if the apps are bit-perfect they don't all sound the same. Many people are looking into this one.

Chris - You are saying 'Many people think USB is vastly superior to TOSlink', but my limited insight into these issues tell me 'it depends'. Granted, the signal may carry a clock with it in one case but not in the other, which may or may not be a big deal. However, some USB DACs convert the USB into SPDIF, so why not use SPDIF right away? Like for everything else in an audio system, it comes down to what reaches the ear, and I am sure that most users won't notice any difference between USB or Toslink.<br />

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Also, what makes the AE a mid-fi component? Isn't it simply a transmitter, i.e., the optical signal emerging from the AE should be pretty much identical to the optical signal coming out of a Mini or Powerbook. Are there any clock or other issues that make the AE a lower-quality component?<br />

<br />

Best - MM

Hey MM - Thanks for the post. I agree with you 100% when you say, "It depends."<br />

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Why not use SPDIF from the beginning? If you ask 10 manufacturers you may get 10 different answers. Some manufacturers convert USB because they think their equipment sounds better this way. Others may convert to I2S for the same reason. At first blush you may think that converting the signal would cause degradation, but some extremely high end manufacturers say it does not. Thus, offering USB provides another input option and a great one for computer based audio. <i>Almost</i> every manufacturer I talk to dislikes TOSlink and the jitter that comes along with it. In fact some manufacturers would include USB only if they could get away with it. On the other hand, Benchmark says its DAC1 PRE sounds exactly the same via USB or TOSlink from a MacBook.<br />

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As far as the Airport Express goes I believe the amount of jitter associated with it is pretty high and for best performance requires a reclocker like the Empirical Audio Pace Car. I certainly no engineer but I think adding wireless transmission and another device (AE) into the audio chain is vastly different from a direct connection between the MacBook and a DAC via TOSlink.<br />

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I will see if I can get in touch with someone much more learned in this than myself and see if they'll post a better answer.

"You are saying 'Many people think USB is vastly superior to TOSlink', but my limited insight into these issues tell me 'it depends'. Granted, the signal may carry a clock with it in one case but not in the other, which may or may not be a big deal. "<br />

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It does depend on the USB interface. The better ones will definitely outperform a Toslink interface, given that the data source uses identical clock generators.<br />

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Both S/PDIF (includes coax and Toslink) and USB encode the clock and the data into a single signal. In this respect they are very similar. Neither one has a separate clock.<br />

<br />

"However, some USB DACs convert the USB into SPDIF, so why not use SPDIF right away?" <br />

<br />

The DAC's that convert USB into S/PDIF are introducing more jitter than necessary. Sometimes this is done in order to get galvanic isolation, but other than that or convenience of design, it is a negative IMO. To keep the jitter as low as possible, the optimum solution is to go directly from USB to I2S to the D/A chip. I2S, which has separate clocks, is the native interface for the D/A chip. S/PDIF is not. S/PDIF is an intermediate interface created to be convenient and inexpensive for a cabled interface. Toslink is the optical version of the S/PDIF interface. Toslink has all of the same negatives as coax in that it encodes the clock and data into a single signal and then a receiver chip must recover the clock using a PLL. Introducing a PLL into the clocking chain ALWAYS is a negative, particularly if it is an analog PLL, which most receiver chips are. This introduces more jitter. In addition to this negative, the Toslink has the negative of converting electrical to optical and back to electrical. This conversion process itself introduces jitter. Much more jitter than just buffering an electrical signal.<br />

<br />

Tolink is at the very bottom of my list of methods to stream digital audio data.<br />

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"Like for everything else in an audio system, it comes down to what reaches the ear, and I am sure that most users won't notice any difference between USB or Toslink."<br />

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This is where you are dead wrong. IF your system is a resolving one, with decent imaging and HF extension you will easily hear this difference. If you buy a cheapo USB interface, maybe not.<br />

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"Also, what makes the AE a mid-fi component? Isn't it simply a transmitter, i.e., the optical signal emerging from the AE should be pretty much identical to the optical signal coming out of a Mini or Powerbook. Are there any clock or other issues that make the AE a lower-quality component?"<br />

<br />

Yes, definitely. The jitter from the Toslink output of the AE is atrocious IMO. One of the worst of the WiFi servers on the market. Improving the internal oscillator inside it (my Off-Ramp WiFi product) makes an obvious improvement, as does changing the output to S/PDIF coaxial. <br />

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Reclocking it through a Pace-Car reclocker makes an even bigger improvement, so I have discontinued the Off-Ramp Wi-Fi. <br />

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What you will hear is more detail, clarity, dynamics and less background noise. The Pace-Car details are here:<br />

http://www.empiricalaudio.com/frPace-Car.html<br />

<br />

This lowers the jitter to levels that even CD players and Transports cannot match.<br />

<br />

Steve N.<br />

Empirical Audio<br />

<br />

Thanks for the great summary! That cleared up a few things.<br />

<br />

You said: "This is where you are dead wrong. IF your system is a resolving one, with decent imaging and HF extension you will easily hear this difference."<br />

<br />

This is certainly true, but it is a trivial statement ("trivial" in the scientific sense). Of course, IF the system can resolve the differences, then one MIGHT be able to hear the differences. However, I wonder how many people actually have systems that are able to resolve the differences between a USB and a Toslink connection. And I wonder how many people are actually able to hear such differences. People will have to try it out in their systems.<br />

<br />

In any case, it's great to see computer-based audio systems finally going high-fidelity.<br />

<br />

Thanks again. Best - MM

Re: the issue of "how much" DAC you need, I am developing something of an opinion. I get the opportunity to compare many products in the store, from $300 CD players to 10K. At one point we sold and I owned the Mark Levinson 31.5/30.6 transport/DAC combo. The transport was 9K, the DAC was 17. There was a model below each of those two pieces that was substantially less expensive, I think it was 4 for the transport and 6 or so for the DAC. The surprising thing to me was that if you were going to have one of the reference pieces and one of the lower priced ones, the better transport had more of an impact on sound than did the megabuck DAC.<br />

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The reason I think this is an issue in Jeff's question regarding the DAC in a CD player is that I have found it takes a great transport to match the results you get with a server. I have done a lot of experimentation in the store since I have jumped on this bandwagon. That being the case, I believe, and I am still working on this at the higher performance levels, that the inherent advantage of the server providing your signal provides higher performance with a DAC of the same quality as what is in your CD player. Whether this is due to lower jitter, error correction or what I am not qualified to say but I think this is a distinct advantage over the traditional CD player and allows you to save money or improve performance. This example does ignore the investment in the computer you are using but it does apply to the DAC.

<cite><br />

unless you are using something like XXHighEnd, which is still in beta, supports only .WAV files<br />

<br />

plus FLAC and MP3 (and DTS passthrough) at all common sample rates and bit depths.<br />

Why provide wrong information ?<br />

<br />

:-)<br />

</cite><br />

<br />

My mistake, Peter. I thought you had said at one point that XXHighEnd only supported .WAV. My information must be outdated. My apologies. :-(