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Music Server Computer transport - Hop On!

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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.
DIY - Done Right!

Follow Ups:

Some Hard Data and Comments - bcherry 22:20:03 12/14/09 (0)
OK an on-the-ground tech report:
"I had an unmodified Musiland for use as simple SPDIF generator and found my receiver had problems locking consistently (I was debugging the software control for this receiver). Putting a 'scope on the signal out of the musiland showed as per attached, left.
The actual signal level is around 200mV peak-peak and there is a huge 100mV spike on each transition.
First, this is WAY below the IEC 60958 type II specification of 0.5 - 1V peak-peak (and low enough that some receivers designed to this standard will not trigger reliably). Secondly the waveshape is UGLY. And NOISY. Brrrr... No wonder the poor receiver was constantly complaining about unlocking.
Okay, out come the original transformers to be replaced by the "magic part" (sorry, cannot reveal which, it is pretty decent but most important it's parasitics are consistent and I know what they are).
Remove the original disastrous resistive divider. A corrected divider was applied AFTER the transformer, with an impedance that correctly terminates the transformer; drive is now from a very low source impedance (the buffer in the Musiland is < 10 Ohm Z-Out).
After that the trace was much more like it, correct levels at around 0.8V Peak-Peak, minimal rining on the edges, but the traces where still furry. So I added an SMD CLC filter (1uF/0.1mH/1uF) between USB input and main circuit (musiland has a place for a choke on the PCB but does not fit, shame, things would be much quieter with choke) and I added a 220uF/10V Os-Con as bulk filter capacitor. Now the traces are not furry anymore. Right picture but different scale as output level different.
A quick before/after listening test showed that most of the hard and mechanical sound quality has gone, now we do not only get all the bits, but most of the music as well.
Doing the full mod with clock and separate supply is still quite a bit better, but the basic mod also gives a major step up in sound quality. Oh yes, and I can go back to debugging my receiver control software, for now we have a lock absolutely rocksteady (and the clocks out of the receiver are SO MUCH less jittery, before you could see the jitter with the naked eye on the 'scope!)..."
DIY - Done Right!

Edits: 12/14/09
Music Server Computer transport - More. - bcherry 00:46:41 11/23/09 (0)
Musiland USB to DAC:

We left off last time with the resistors in place of the pulse transformer to the SPDIF. Getting rid of the transformer and adjusting the output to 75ohms really opened up the sound.

The new transformer parts arrive and we install one in place of the resistors. The other output still has the resistors so we are able to A/B:

Nov 20
Today we installed the upgraded transformer into 75ohms and had a preliminary listening A/B between Rout and TXout. I'll write more later after we do something more extended but briefly:

There were 4 of us and 3 didn't know which was which, Rout or TXout. We listened to one track, about 8 passes. After the first pass 2 of 4 listeners choose Rout as better detail and bass, 2 listeners choose not to comment.

By the third pass the tide changed to favour the TXout and by the last pass it was unanimous the TXout was best. It took a few passes to identify that the extra detail was really a kind of aggressiveness and the bass was somewhat exaggerated.

All agreed the TXout had more real detail and more tuneful bass. Dynamics were about the same. The listeners liked the word 'natural' to describe the TXout. Next week I'll check out some bass heavy tracks to find out if the lows are rolling off at all. I'll then install a TX in second output with a little different loading. Once we get a winner there then I'll do the BNC connection.

Nov 23
We confirm all the bass is still there, just less overhang. More listening also supports the differences noted above.

Comparing CD transport to Computer transport -- Round 2:

Today we compare the current setup to the CD transport. Earlier we were unable to hear a difference which is a first for our listening panel. We have 5 persons in our panel of listeners today,-1 female, 4 males and ages 25 to 40 except for me, saying goodbye to my 5th decade. I do the switching between CD and Computer transports, the others don't know which is which.

Music is a track from a Stereophile disk: Rendezvous. The first track leads in with some very delicate cymbal sounds. The second round was Michel Buble Fever and then Robbie Williams Straighten Up and Fly Right.

Once our ears 'warm up' we do hear differences between transports:
3 listeners feel the Computer is more natural and retrieves more hall sound, ie ambience. One listener says the CD transport has a faster pace and is more lively. The #5 listener can hear no differences. 3 feel the Computer is better overall, one chooses the CD transport -- all by a small margin.

Both sound very good. It seems we are now at a level where differences are more a falling of the shadow rather than markedly better or worse.

Next we'll turn attention to the computer power supply. We want to get rid of that SMPS brick and power from a regulated linear supply. We need 19v/3.9A and I think we can do that with a substantially heat sinked filament supply.
DIY - Done Right!
Music Server Computer transport - Is It Worth the Effort? - bcherry 22:22:37 11/10/09 (4)
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'.

regards
Brian

DIY - Done Right!
- Music Server Computer transport - Additional - bcherry 15:56:01 11/11/09 (3)
  I have a CD94 here and had the Tentlabs CD player for a year - both CDPro based. But the one we use day-to-day is a prototype that never got into production. It uses a Sony transport and compares favorably with the CDPro machines.
  
  The clock wires actually connect to the reclocker module; I just unplugged it for the picture. ... piggy back installation would be theoretically better but I didn't try it. Basically we just wanted to use what we had at hand as we sell the EZ Clock and Power supply shown as well as the regulated power supply (actually a DHT filament supply so very ideal for this). The items are listed under 'active modules' menu.
  
  Transformer removal: I'll let the expert who did this explain his reasons.
  
  "The Transformers used are not that great and do not handle higher levels well.
  
  I have found that receivers of the cirrus logic ilk benefit from more signal than the normal 0.5V P-P.
  
  So what we have done is place a low value resistor in the ground leg (10R - IIRC) to provide some ground loop isolation and a second series resistor with the output of the driving gate, to bring the impedance close to 75R, ...
  
  This way we get around 1.5V P-P into 75R.
  
  We will eventually fit different transformers that handle more level and have a better waveshape, for now removing them was a better option. ..."
  
  ...the 3.3v and 1.2v regulators are in the queue to receive some attention, among other things.
  
  I'm not sure what contributed the most to the improvement as I only took a serious listen after all the mods listed were done. But it was well worth it and there seems to be more potential for improvement. A computer transport that beats a standalone cd transport seems to be within reach.
  DIY - Done Right!
  - Where We Are and Why - bcherry 17:52:13 11/18/09 (2)
    The replacement transformers have arrived. I'm just waiting for some SMD parts and then we will:
    - leave the RCA output with our resistors and 75ohm cable untouched
    - install the transformer on the second out and connect (with some SMD parts) that to a 2nd RCA output. This will allow us to switch between the current output (which is already significantly better than stock) and the output with the upgraded transformer.
    Thanks for the comments; I'm very interested in the other ways mentioned and will get one of those devices to compare.
    Some have asked why we are doing THIS instead of THAT.
    This is a vendor's forum. The idea was to see how far we can go with what we have on the shelf using the commonly and cheaply available Musiland (which gives us 24/192) and a computer transport.
    To recap:
    The Musiland needed a good clock, power supply, and the right cable. These things removed much of the performance bottleneck.
    In addition the chipset likes and is able to swing more voltage so we made the circuit changes for that, but the transformers (already marginal) were unable to keep up. So we used resistors and this has taken us to the current level of performance.
    Now we have the upgraded transformers and will try the next phase described.
    Regarding some of the other ways to get digital music playback I received this interesting email:
    
    "Brian,
    I had a look at several of these Media Streamers. Reviews of many can be found at the MPC Club website, they are worth reading for the comments on the music side of things.
    I do not wish to comment on the SPDIF output implementations in these machines, but yes, they work and bitperfect if the volume control is left at full.
    All these machines have a most basic software and interface section for the Music part.
    Worse, none to the best of my knowledge handle music playback in "gapless" mode, absolutely essential if live or classical albums are ripped into seperate tracks (or indeed such items the recent "Love" Album made from The Beatles back catalog or something like DSOTM by Pink Floyd.
    The only way around this would be to rip such albums as complete images, in that case these players lack the support for .cue files that allow individual track access in these whole CD Images.
    This basically precludes their use for music playback if one listens to anything where gaps inserted between tracks are unacceptable."
    DIY - Done Right!
    - MPC (Open in New Window)
    Edits: 11/18/09
    - Brian, please check out M2Tech - Jon L 11:06:35 11/19/09 (1)
      It's great to see what you are doing to improve sound quality on these devices. I have owned and tried various USB-to-spdif devices, including the pretty tricked-out ones from Empirical Audio.
      
      At the current time, the one that really catches my eye is the M2Tech converter, which reportedly already has great sound quality in stock form.
      
      It's only around $150, small, and does not require USB cable. Not much is known about what exactly is inside, but I can already see that disabling its USB-bus power to something else, even simple battery, will improve it a lot.
      
      Since you mentioned you will be testing other devices, please consider the M2Tech device as well!
      USB-to-spdif shootout (Open in New Window)
      - RE: Brian, please check out M2Tech - bcherry 00:49:33 11/23/09 (0)
        
        In Reply to: RE: Brian, please check out M2Tech posted by Jon L on November 19, 2009 at 11:06:35
        
        Thanks for the link. That one looks interesting too. What a hullabaloo over USB cable length!
        
        DIY - Done Right!
RE: Music Server Computer transport - Hardware Attack! - bcherry 20:18:31 11/05/09 (6)
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. Is it worth it?
DIY - Done Right!
- Hardware Attack!... Re: Is it worth it....? - Frank Mena 06:16:53 11/06/09 (5)
  You can't leave us hanging with that last sentence......
  So was it worth it?
  
  Cheers
  Frank M
  - RE: Hardware Attack!... Re: Is it worth it....? - bcherry 02:16:37 11/10/09 (0)
    Hi Frank. Thanks for your patience. We did one listening session to A/B the computer transport (with modded Musiland) and standalone transport. There were 4 persons and no one could hear a difference. I haven't posted it yet because I wanted to get some fresh ears and do it again to confirm/refute the results.
    regards
    Brian
    DIY - Done Right!
  - Of course it's worth it! - Jon L 13:21:10 11/07/09 (3)
    Having played with lots of USB-to-spdif gears, even some pretty tricked-out ones, I feel this is the bottleneck in most systems that use these devices, even the one pictured.
    
    I'm sure the modded box greatly improves sound, but ultimately one would want to use a non-USB solution, unless one can come up with completely asynchronous USB interface, powered correctly...
    - ) asynchronous USB interface, powered correctly... - The Artful Bodger 07:33:09 11/08/09 (2)
      Yo mon,
      
      I ain't so sure about the details, but the Musiland gizmo thingeymaboby seems to work asynchronous, it certainly does not work as traditional USB device (transfers data in bulk mode using it's own driver, did not waste much time with this thing).
      
      It uses on board pll to make the audio clocks from a single crystal (not a bad thing itself - the "nah-nah-pll" sayers not withstanding, the TC firewire solution used by Weiss does the same and well).
      
      What dat sez iz - a dirty power supply will make trouble. The crystal circuit also runs of the same dirty chip power taken from USB, I'd say we have double trouble, when we want no moh troubles.
      
      We have a jittered clock we use as referee for a fractional division pll with vco badly modulated from supply.
      
      Who just said "Desaster Area"? Was that you Zaphod?
      
      My Musiland sounded much worse than me modified spdif motherboard. Dub no ear good. So me send it back.
      
      No idea how good these supplies and clocks are, but what the guys at diyhifisupply are doing should help the problems well, so no reason dub not ear good!?.
      
      Seems an awful bodge though, not very artful at all.
      
      Greez TAB
      - "Properly Done USB" is like the Unicorn - Jon L 11:30:05 11/09/09 (1)
        
        In Reply to: RE: ) asynchronous USB interface, powered correctly... posted by The Artful Bodger on November 08, 2009 at 07:33:09
        
        I found John Swenson's post on the Musiland.
        http://db.audioasylum.com/cgi/m.mpl?forum=pcaudio&n=59851&highlight=musiland+john+swenson&r=
        
        So much for that, as it seems Musiland's asynchronous is not the proper asynchronous USB implementation at all..
        
        RE: "Properly Done USB" is like the Unicorn - bcherry 02:10:39 11/10/09 (0)
        
        In Reply to: RE: "Properly Done USB" is like the Unicorn posted by Jon L on November 09, 2009 at 11:30:05
        
        Not sure why is that.
        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. That's all.
        regards
        Brian
        
        DIY - Done Right!
        
        Edits: 11/10/09 11/10/09
RE: Music Server Computer transport - Round One. - bcherry 00:24:26 11/05/09 (0)
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!
DIY - Done Right!

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