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Old 4th November 2009, 02:43 PM   #1
bcherry is offline bcherry  Hong Kong
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Default Music Server Computer transport - Hop On!

I first saw one of these demo'd about 5 or 6 years ago at CES. It was a big brute floor standing computer, loaded with rips of CDs and driving some really nice high end gear. Since then they've become a common sight at high end shows everywhere but I've always found the performance spotty and not that attractive. It's been mentioned in several show reports too.


I don't really understand all the issues and problems at work but we've had someone with us this week who does. Well, my CDpro-based transports are by now getting a little long in the tooth, there's nothing comparable on the horizon AND my CD collection is showing wear and tear -- I decided it is time. So I was given a shopping list.


Here's what we want to do:
1. Use a computer to rip, store and provide playback functionality. Preferably a touch screen with remote as this one can not be used for any other purpose once optimized for music playback. We need about 1 terabyte of storage to start.

2. connect the digital playback stream from the computer to our DAC (in this case the Satch) and then onto all the usual tube based linestage, amplifier and full range speakers. BUT we don't want the terrible-ized sound of the computer's onboard sound card. It's really ugly, folks. So we will take the signal, bit perfect from the USB through ASIO.


Here's what I bought:
1. MSI Wind Neton All-In-One, 19" Touch Screen
2. WD MyBook 1 terabyte (2 pcs, one for backup)
3. Musiland Monitor 01 USD USB (much discussed in the forums as it converts the ASIO usb output to SPDIF and allows 192khz/24bit)
4. Windows MCE Remote with receiver
And here is the picture of the MSI Wind Neton as set up. the black box contains the usb to DAC interface. More about that in the next blog.
Click the image to open in full size.
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Old 5th November 2009, 08:27 AM   #2
bcherry is offline bcherry  Hong Kong
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Default Music Server Computer transport - Round 1!

Click the image to open in full size.
OK so all the bits arrived, we connected them together: MSI Wind Neton>>>Musiland USB to SPdif>>> the Satch DAC>>>UTS-UVC linestage>>>Fusion>>>LCAO full range speakers -- something like the picture save the black box in the centre which came later.

First task: configure the digital playback stream to bypass the computer on board sound system and output through the USB>>Musiland. I download an ASIO music player and got some music to play that way.
OK, better than using the sound card, but not as good as our standalone transport. But there is still much we can do, so -- promising.

Now aforementioned expert arrives on the scene. Here's how he explains the issues:

" ...both the Apple Macintosh and PC Audio core build into the operating system are not designed for absolute quality, but for
convenience, which raises some interesting issues.
By default, none of the existing computer configurations offer a “Bit Accurate” digital output, regardless of the connection method used. Instead CD audio is always resampled to 48KHz to comply with the Windows Audio standard set down under the name Audio Codec '97 (AC97).
This means in order to get a PC to perform as well sonically, as a good quality CD Transport (or indeed better than most, to which it has the potential) we need to bypass this operating system audio section."

The computer we choose for this task is an All-In-One, meaning screen, cpu and all hardware is mounted in one chassis. Like a notebook it has a fan which comes on based on system temperature. In this case we don't want a fire breathing screamer as those things are a Dante Inferno of heat and noise, which is bad for the perfect bits we want.

He goes to work stripping out bloatware from the OS (XP) and setting bios to use minimum of system background resources and background processes. In the end, playback only uses about 5% of CPU. Now all the Media Portal software, skins, plugins and latest Musiland drivers are installed. Not a small job and it takes the expert most of the day to get it configured.

CD's are now ripped with the correct plugin and we listen.

Better!
Still not up to the separate CD transport, but we've taken a big step forward and we still have the hardware to attack!
Interesting we try an A/B playing a CD by the on-board CD reader compared to the same ripped and playing from the hard disk. Very similar but after listening for a while it is apparent that the CD reader is just a little less good than the ripped CD, less space, less openess and detail - just a little but definitely noticeable.
The expert explains this is probably because the CD reader puts a load on system resources which dulls the sound.

OK now for a little reconstructive surgery - not for the squeamish!
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Last edited by bcherry; 6th November 2009 at 05:21 AM. Reason: spacing
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Old 6th November 2009, 04:21 AM   #3
bcherry is offline bcherry  Hong Kong
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Default Music Server Computer transport - Hardware Attack!

OK the Magic Black Box.

Much has been written about the Musiland computer-to-external DAC enabler. Just plug in the USB data stream from the computer and out the provided SPDIF comes our DAC friendly perfect bits, even up to 192khz/24bits.



That's pretty good news. However there are 'issues':
1. the Musiland is powered through the USB cable, drawing trashy DC from the computer's power supply
2. the on board 24mhz clock signal is a total disaster
3. the electrolytic caps are undersized
4. the 2 pulse transformers massacre the data stream
5. some parts values are not ideal
6. 75 ohm digital friendly cable is not used
7. the input side circuit can be greatly improved with some simple changes


So we remove the (cough, cough) clock, 4 of the SMD resistors, the 2 pulse transformers, the 5 10uf caps, the offensive wire and replace with suitable bits plus some hocus pocus to the circuit performed by the expert.
We power the pcb with the DIYHFS VCS regulated supply driven by its own power transformer


We feed the clock signal from the Ultimate Clock and Power supply system with a shiny new .5ppm 24mhz OSC.


All is installed in the Black Magic Box as shown.


Now we have the Musiland DAC enabler where we want it: untethered from the computer power supply and operating with lowest jitter from a proper clock which has its own power supply.


We put the box together and reconnect the system.



Click the image to open in full size.

Is it worth it?
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Last edited by bcherry; 6th November 2009 at 04:22 AM. Reason: space
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Old 9th November 2009, 04:29 PM   #4
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Quote:
Originally Posted by bcherry View Post
Is it worth it?
And was it worth?

I have a Musiland 02 US that already has an internal PS and I'm also thinking of replacing the crystal with a Crystek clock.
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Old 10th November 2009, 12:15 AM   #5
ejfud is offline ejfud  United States
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I'd like to hear about the speakers in the picture. They look interesting Brian.
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Old 11th November 2009, 06:27 AM   #6
bcherry is offline bcherry  Hong Kong
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Default Music Server Computer transport - Is It Worth the Effort?

Click the image to open in full size.

So we finish the previously described modifications to the Musiland and install the Magic Black Box. The system boots up and recognizes all hardware. After a ten minute warmup we play music.


Playing 'Dreams of Likembe' we hear bass notes that weren't noticeable before. Soundstage is more focused and detailed, less starined. In fact a pervasive 'hardness' that was there before in varying degrees is gone.


This is a big step forward. The effect of swapping bad clock/good clock is sometimes subtle, sometimes way obvious depending on how much it's needed. In this case it is very obvious. If you've used vinyl playback it most reminds of what happens when you tighten up a cartridge that is loose in it's headshell -- things snap into focus, bass goes deep, there is more dynamic spread and less noise/more music.


But the real question is how does it compare to a standalone CD transport. Are we close?


We have 4 listeners present. We cue up the CD transport and the Computer transport - each playing through a Satch DAC. For about 20 minutes we play tracks from All For You (great voice) and Mozart Salsburg Sympnony (great strings), switching back and forth without knowing which is the source.


We can't hear a difference. This is the first time that happens (usually we hear a difference but may not be sure which is better until after a long listening session).



It may be that something else is masking the difference because surely there must be some. I plan another listening session with fresh ears and music (actually that listening session fell through as the 'ears' didn't show when expected so will do this later). We will either confirm or refute the result.


In either case this is encouraging because there are still more things we can do to make it better:
A linear DC supply for the computer to replace that SMPS provided.
Underclocking the CPU (we are only using 5% so if we underclock by 50% or so we can get rid of a lot of heat/noise, ie turn the hose on Dante's Inferno).

One other thing which we'll try before mentioning as it's a little 'unconventional'.


The question was asked if the Musiland really is asynchronous? Something to help understand the issue and food for thought:

asynchronous:
"In a synchronous system, operations are coordinated under the centralized control of a fixed-rate clock signal or several clocks. An asynchronous digital system, in contrast, has no global clock: instead, it operates under distributed control, with concurrent hardware components communicating and synchronizing on channels."


So either it is or it isn't. The Musiland uses an onboard local clock and its own driver instead of an MS driver. I'm not sure that is an issue relating to sound quality.


The key here is how good the audio clock is. Being asynchronous means its output jitter depends on how good the Musiland audio clock is.
In the Musiland a simple 24MHz clock generator is used that runs off the main powersupply, which is fed directly from the PC's USB power line. This will create a very jittery reference clock for starters.


This clock forms the reference of a "fractional division PLL". Such a PLL is used to make non integer multiple clocks from a reference clock. It can never be any better than the reference clock. The DIYHFS EZ Clock with a 0.5ppm clock generator provides as close as possible to the ultimate as reference clock, eliminating this issue.


There are many varying PLL implementations, however a crucial thing here is that the PLL will contain another clock generator which is MUCH more subject to jitter from power supply noise. So by feeding this PLL a clean supply, jitter is minimized.


Purely from a viewpoint of potential jitter (which we cannot verify as having been achieved or not) the Musland system (the chips used) seems to be capable of sub 100pS jitter results, something the Musiland guys also claimed (but their actual design does not achieve it).


All that said, the common Cirrus Logic (Crystal) Receivers and most others add over 100pS jitter of their own, so I should think the SPDIF Receiver would be the limit in the DAC.


If receivers used have low jitter of their own and equally good suppression of external jitter, all of this is moot anyway.


The Musiland is cheap and the mods done do not cost the earth either (there are more expensive USB2SPDIF boxes out there that do less). So I think one can easily defend the Musiland USB to SPDIF converter with modifications as a good way and economical way to make a computer transport for a pre-existing SPDIF DAC capable of 24/192KHz.
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Old 11th November 2009, 06:31 AM   #7
bcherry is offline bcherry  Hong Kong
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Quote:
Originally Posted by ejfud View Post
I'd like to hear about the speakers in the picture. They look interesting Brian.
Thanks. These are the LCAO hand made drivers from China. You'll notice there is no whizzer, instead using concentric sections of paper so the innermost acts as a tweeter. They have very extended hf for a full ranger.

They need a big box and best placed against the wall. I had them for about a year and just now come to like them setup as shown.
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Last edited by bcherry; 11th November 2009 at 08:16 AM.
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Old 11th November 2009, 06:33 AM   #8
bcherry is offline bcherry  Hong Kong
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Quote:
Originally Posted by danny_66 View Post
And was it worth?

I have a Musiland 02 US that already has an internal PS and I'm also thinking of replacing the crystal with a Crystek clock.
Yes, very much so! No experience with the 02 you have but if it's anything like the 01, there is much to be gained with a good clock and discrete PS.
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Old 11th November 2009, 08:41 AM   #9
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hello bcherry,
Nice review!
Finally there's a transport that can change my portable in a high quality music server.
Do you sell such a clock and PS?
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Old 11th November 2009, 02:02 PM   #10
jkeny is offline jkeny  Ireland
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BCherry,
I just saw this thread now as Danny pointed me to it. Nice set-up & fully agree with your conclusion about the Musiland.

I have done similar mods to my Musiland 01US & would have compared notes sooner if I had seen this M2TECH Hiface USB->SPDIF 24/192Khz asynch

Can I ask some questions:
- What CD transport are you comparing to? (Edit: I see now it's a CD-Pro based one! I presume it's good?)
- Your new clock that replaces the on-board crystal seems to be off-board connected by twisted wires - would there be any advantage to locate the clock closer to the Cypress? (Edit: Is this a Tent Labs clock module?)
- You also seem to have a reclocker in the pic, does the output go through this?
- You seem to have replaced the SPDIF transformer by 2 resistors - can you give values & say something about this mod
- Similarly, you have taken out USB socket and put in 2 resistors - can you say about these
- Did removing the Toslink improve matters?
- Have you tried to change/remove the on-board 3.3 & 1.2V regulators?

So many questions that I would have been asking along the way but now all come together - hope you don't mind?

In my mods, so far, I've found the external PS to be the biggest improvement, the clock change probably on a par with it but I need to live with it for a while yet to evaluate it's contribution. My other significant mods have mostly been to the output stage of the on-board PCM1793 DAC.

Last edited by jkeny; 11th November 2009 at 02:10 PM.
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