STOP PRESS. NaimDAC v's ND5 XS: Dealer comments.

Hi,

Check-sum is a way to ensure that the information sent from a computer here the Userve to another here the nd5 is correct, if not the information is sent again.

computer decoupling I am not sure about that. The idea could be to place the Userve in another location than the hifi. You can find threads on this forum about different forms of electrical noise that you do not want transmitted into the hi fi, but that is the case both for coax and network cables. That is why it is adviced to use chokes on both  type of cables.

Whenever somebody ask about what Naim streaming system sounds best especially the servers, you do not get an answer but a lot of advice like, get a mac or a vortexbox.  These are interesting an cheaper options, but not for all.

But if you want to get into streaming you could get a system with a mac mini or a pc running Vortexbox and Ndx for the same money a Userve and nd5 will cost.

If you want the Userve, then your dealer should be able to show you both systems. In theory his reasons for preferring streaming sound good, but who knows if it also holds true when you listen to the system.

Currently the Naim streamers can provide more meta data and extra information on the n-stream app, but this will most likely come to the n-serve with the next update.

Claus

Hi Jason

Your basic question is a good one : ndac + userve or streamer + userve, with units at the same price point which boils down to a digital out versus upnp argument.

Its a question I only briefly considered when I chose my NDX because I had previously heard the bare ndac and thought its treble a bit sharp for my ears, especially when compared to the more rounded NDX.

So i made mydecision accordingly and never got round to a side by side comparison. I would be interested to hear the opinions of those who have though and whether there are technical reasons for the superiority of one format over the other.

Ray

Jason,

To answer one of your questions, the same coax cable goes between either the ND or the US into the DAC.  Some have said here that the digital-out from the US is not the primary aim of the US, the way it is on the HDX, which costs a lot more.  The HDX is designed to be a true one-box player and server.

But I would not take this simply on faith.  I find it hard to believe the US sound quality does not equal or beat a Mac Mini (which sounds great) performing the same functions into the DAC.  I have not done the listening test myself.  Let us know what you think.  The US may be a brilliant player/server in your setup.

All I can say from experience is the new nStream seems to address the items missing I care about vs nServe, and adds Volume and source-selection, and CD player control.  ND-something will be my next addition, with a US coming after, maybe.  

Good luck.

Nick

I have four systems involving three Unitiserves and one NDX. During the day I listen to the Unitiserve into DAC and PMC IB1S monitors (currently playing as I type). In the evenings I listen to my main system which streams from my home Unitiserve via my NDX/XPS/DAC into B&W 802 Diamonds. At home in France I listen to another Unitiserve into a DAC and PMC DB2s/B&W 804s. Finally in the family room the Unitiserve is connected into an Onkyo AV processor using Naim's big in ceiling speakers.

I have tried just about every combination and I cannot discern any difference no matter how I access the data from the Unitiserve. Speakers makes a huge difference, as does room treatments with the bigger speakers. The choice of DAC must be done with careful auditioning (the Onkyo in particular is harsh). This may be a deficiency in my ears but I keep swapping these components around and can always obtain the same sound from the Unitiserve given the same DAC. If your setup tends towards the lean the DAC in the NDX has a big boost in the response above 200Hz the seems overblown with my 802 Diamonds and PMC IB1S but may do it for you especially with Naim speakers. As soon as the external DAC is put back in the sound is identical.

Dealers may feel that the Unitiserve should just, well, serve. However in my daily listening supports your instinct of Unitiserve/NAIM DAC into your pre-amp and amp. 

The Unitiserve is such a great UPnP server so a bonus is that every other device can stream from it and suddenly all my staff found my music appear on the network.

Ian

> I cannot discern any difference no matter how I access the data from the UnitiServe

My theory is that is because there isn't any.

If you serve the Naim DAC from a good source then it is very happy to play music .... UnitiServe or Mac Mini - it doesn't really matter. The DAC and what comes after makes a lot more difference.  

Well, what can I say, in my view some dealers tend to turn a rather simple process into something complicated, either because they don't know better and just repeat the "Naim line" or because it suits them. If you were cynical you could look at it as a "keep the customer 'stupid' and reap the rewards" type of approach. I am not saying your dealer is of that type, maybe he actually believes what he says. And just maybe he is right in technical terms. My understanding of the nth degree regarding these technical aspects is not deep enough, so I wouldn't know. But the real question is, does any of this matter with regards to daily use, sound quality at the level you are looking at and in the context of your system? I would argue, if it did apply, not in your circumstances, maybe at NDS/500 level, don't know. Ultimately you need to go by what you hear or don't hear. No voodoo involved here. I can honestly say, from personal experience, that the nDAC is a great leveller with regards to what it gets fed and the sound quality (analogue signal) it passes on to your amp. Blimey, it's what it was designed for, jitter free processing of S/PDIF inputs. However, I remember having a listening session at a dealer and I was able to differentiate between a CD5XS and CDX2.2. feeding the nDAC. The difference was audible, the CDX2.2 sounded 'better'. So I am not saying different inputs/bit streams cannot be distinguished between. BUT since owning the nDAC myself I have compared various sources feeding it and my position today is that the differences are minor, if at all audible. My modded Sonos ZP90 (€349 for the Sonos ZP90 + €300 for the low jitter modification by Dr. Gert Volk) sounds pretty much the same as my CDX2.2, both into nDAC/555PS via Naim's DC1 coax cables (ACR and BNC respectively). If there is a difference, it certainly is not worth €4349. The CDX2.2 costs €4998 at list price. Even AIFF files from my MBP's digital out via a €10 plastic optical cable sound pretty much on par. Even 320 kbps mp3 files sound astonishingly good. Go figure. I had the ND5XS for a good few months at home and decided to sell it again because to me there was no discernable difference between it and my modded Sonos when feeding the nDAC. To me it wasn't worth the extra cash. I also preferred the simplicity of the Sonos as well as its UI. Doesn't do hires but who cares, not much around for the music I am listening to anyways. Red Book CD quality is good enough IMO. All methods mentioned by me are pretty safe it seems, no loss of data I would need to worry about. I would also argue that you will not hear a difference between a file served up to your ND5XS and one being fed via coax and if you did, it would be negligible IMHO. When the US first came out plenty of dealers here were singing their praises what a good system US/nDAC is. Now it's not good enough and the ND5XS route is safer and better? I doubt it. FWIW, I spoke to the Naim distributor here in Germany one day regarding the US/nDAC combo and its SQ versus CDX2.2/nDAC and the chap I spoke to reckoned the US sounded better. Is it true? Don't know. One thing is for certain though, it will sound very good. Bottom line, to many here the nDAC will sound 'better' than the ND5XS. Does it to you? I maintain the point I have made in earlier posts, don't underestimate the importance of a balanced system. I am certain ND5XS/Nait XS can be all you'd ever wanted. In the end it comes down to the way you want to play your music. Do you want a streamer? If you do the ND5XS is a great unit. Do you want even better SQ? That's the nDAC for you. You need to be clear though on whether the US is worth the extra money to you that it costs because you can get the same SQ from your nDAC using other sources to feed it. And ripping in iTunes really is a piece of cake. Use XLD, if you are sceptical and need to calm your mind. But to say that serving data over the network and streaming with the ND5XS is better than a MacMini or US via optical or coax into nDAC is far fetched IMO.

Let your ears be the final judge.

tp

> What is "computer decoupling"?
> What is the "check-sum"? 

Computer de-coupling sounds not too nice really .... 

A Mac Mini + Supernova 6 Glass Optical Cable + Naim DAC ... the noisy little computer (not that noisy really) is de-coupled for the DAC by use of Glass Optical Cable because being optical no electrical rubbish can get from computer to DAC. If it used a coaxial cable it would need some way to galvanically isolate the computer, from DAC (a device like a hiFace does this)

The check sum is over £3,000 if you buy the NDX.

Suppose I send the number 1, 2, 3, 4, 7 to you the check sum is 17 (add them all up) - however if a bit gets dropped and you receive 1,2,2,4, 7 then you add them up and get 16 (assuming I've sent you my check sum) .then you know something has gone wrong because it doesn't add up so you ask me to send the numbers again ... of course, just adding them up is not great because 1,2,3,5,6 also add up to 17. So check-sums are usually more complicated sums then just addition so that any sequence of numbers will give a unique result. Also with digital replay you may not notice the odd dropped bit (doubt you can hear 1 in 1,000,000) so if you keep saying send again, send again that is not always a good thing as the network might be rather busy. However in the context of music at home either way will be fine. 

As TP very sensibly says, who cares ... compare a Denon Music Server against the NDX in to the Naim DAC through your system ... can you hear £3000+ worth of difference? If yes then NDX. I have tried this with a UQ in my system and can't hear anything worthwhile over a Mac Mini or Sonos, but all sound better than a Yamaha CDP digital out ... oh well back to drawing board. 

The reason the Naim DAC sounds so good with so many things is simple ... it's magic. 

Why do I need a glass cable?  Won't a plastic one do?

I have tried a few cables ... Belkin & Chord (Plastic), Mark Grant and Wireworld and TCI (Glass) ... the last three sounded better to me and were better made too. 

Wine taste so much better out of a wine glass than a plastic cup, perhaps it is the same with digital audio. 

I think it is mainly the quality of the cable, but the three glass ones rock 

OK, thanks.  Will try a glass cable out.  Not sure why it should make any difference though - it only has to transmit blobs of light.

Some alternative views on data...

The computer view:

1) 01010101111001010001 = an image
2) 00010101011111010010  = a video
3) 01010111111101111100 = a document
4) 11111000000101010010 = a spreadsheet
5) 11000010101010010011 = a music file
Hold in memory, write to disk, send across network, distributed transactions. All fine, even the last one.

The business view:

Store petabytes of data
Add terabytes per day
Move it around domestically
Move it around internationally
Run global currency systems on it
= License to print money. All fine.

The casual punter view:

Send email with picture attachment to friend / boss / lover
Write word document file to network drive at work
Browse websites hosted all over the globe
= The picture is still in the same colours. The word document is not now missing words.  I can view websites. All fine.

The audiophile view:

Will my flac or mp3 make it 5m across the living room to my Streamer / DAC / whatever (not even writing to a disk once).
= Check-sum to prevent data loss??? Lightning strike. Plague of locusts. Panic.

Remember walking into work one day. There was a YTS lad there and he was moaning his arm hurt. I turned around and he was holding one end of an attached cable in mid-air. What are you doing I asked him. His reply? The boss told me to hold it like this to prevent the data falling out.

I went for coffee. It was going to be a long day.

Back on topic. OP, apologies for joking around on your thread. The lighthearted target was the endless debate on the central topics not your questions. Some thoughts on those below:

it is hard and unfair to offer comment on the dealer's comments without hearing his context and understanding.

Given your situation suggest going with Naim DAC - NAC 152 XS - NAP155 (as you had already chosen) but reviewing what feeds that chain.

Guido and TP make many good points.

As Lumos says, 'The Unitiserve is such a great UPnP server'. It is a server. It hosts files and provides them on demand. It is a very good product and has many satisfied users.

It is hard to imagine a situation where the 1's and 0's would commonly be delivered incomplete to a DAV with even the cheapest equipment.

Remember the Naim DAC removes jitter. The method is very clearly explained in Naim's white paper. The data is fed into a holding area and then their own clock times it back out.

Follow a few best practices such as wired ethernet, enough memory on source device, lossless files, no homeplugs etc.

Beware of RF interference. Simon-in-Suffolk, who really knows his stuff, recommends trying RF beads on this forum. For a few quid, check them out.

Right, that's enough from me.

Chaps excuse my absence, its been a busy week, thanks for all your comments. 

Marky Mark - no problem on your light hearted quips, I appreciate your humour. I do get the impression from the previous posts that there is a certain triviality and endless discussions regarding check sums and the like. Fortunately, I am not that anal and have no inclination to be but its amazing how all these little bits of knowledge make the process more fun.....well initially at least I will stalk Simon-in-Suffolk regarding his knowledge on the `RF beads´.

Guido - very useful info that wine tastes better in glasses, I will pursue this to the very end, bottoms up

And thank you for your explanations on `computer decoupling´ very clear.

So as I understand it, if one were to use a glass optical cable, such as the Supernova 6, then my dealers concerns regarding using the coax from the UServe into the Naim DAC, are unfounded?????

Regarding `check sum´ again very clear and precise explanation...I believe I don't care either. However, I am starting to feel the pressure of `caring´ because of the money one spends on these things. If I were to go down the sensible route taken by yourself and TP, i.e. just go with a cheaper option that is equal in sound quality, then I would probably care less than.....the less I care at the moment while not even owning any Naim boxes yet. And its also very interesting to hear on the Forum that many people such as TP and in more dramatic style pjl2 (Peter)  

have indeed downgraded dramatically. I take great solace in noting that TP, for example, regards the XS line as the sweet spot in the Naim range.....I certainly don't think that I would ever go up the chain......................?

TP - what can I say man, smart post! I get your approach to the whole game, in terms of assessing SQ gain over cost. And it certainly sounds like you've been down that road to know how to approach the game/hobby/passion. It seems that there is equally a desire and passion to down grade in terms of cost whilst still keeping the SQ high as there is the passion to climb the HiFi ladder in terms of cost.

Dare I say it, but I am considering this as a one time outlay, 5.5K is quite enough, and thats without considering speakers, or iPad, fraim and other accessories. But TP, feel free to tell me "I told you so" when I get the SQ gain over cost bug, then I am sure I will be back to stalk the dark corridors of the Forum......

Cheers.

Hi Jason, as Guy says computer decoupling is about removing common mode electrical noise (RFI) from any leads connecting from the computer, such as SPDIF. Common mode means the noise is present in signal and ground return. You can use ferrite chokes clamped on coax to attenuate ground return RFI.

Although there are other methods of decoupling such as fibre optic and galvanic isolation for electrical connections such as used I believe by the  NDAC,  however the latter isn't perfect.

The challenge for TOSLINk (SPDIF fibre) is that it it generally bandwidth limited. This means signal rise times are extended, which introduces jitter in clock recovery.

Now although Naim equipment has a good way of recovering the transport clock and synchronising it.. So at the voltage levels representing  1 and 0 (True / False) and their timing is preserved, a small amount of RFI from the electronics recovering this is genereated... Now on the Naim DAC.. Especially I a high resolution system this affects the audio quality. iME.

So what does this all mean

1) for Naim DAC sources you clean low noise electrical sources and choke the extensively.

2) if you use fibre optic use very short lengths and good quality connectorsThorpe important than the fibre itself). This will keep the bandwidth higher. If you need longer lengths of a critical source then glass can (but not always be) beneficial.

3) try and make sure the source is very low jitter in the transport clock. (transport clock is different from sample clock).

Finally don't let people tell you SPDIF/USB etc is just 1 and 0s. It clearly isn't and misleads. 1 and 0 is an abstraction used to explain  conceptual things such as boolean logic. We are talking voltage and their waveforms here and as such the signal is an analogue signal and has to have all the same considerations as regular small signal parameters.

Hi Simon,

Im going to buy some chokes. Do I just attach one at the NDX end or going into the router also? What about from the NAS to the router also?

What size do I need?

Gary

Simon and All

Thanks - your post is interesting and has helped me learn more. I offer a few comments below in case of any interest to yourself or others....

SPDIF / Jitter

In your last para, if I have understood it correctly, you are saying that although commonly known as 'digital', in reality SPDIF is better understood as analogue signals with waveforms. To use an analogy, perhaps these may be considered to be pulses conveying the data. Pulses of electricity on digital coax and pulse of light on toslink.

On the receiving end in a DAC, a buffer compensates for pulses of information flow. Theoretically, it can hold a representation of the entire set of pulses comprising the original file in memory before clocking out the result for conversion to analogue. In practice a fairly steady stream is what happens but the pulses would need to be extreme indeed for the buffer not to manage. Let's say 1 pulse in the first second, nothing for 5 seconds and then one thousand pulses in the seventh second for sake of rough illustration of the abstraction.

The DSP in the NDAC uses a RAM buffer. This is significant because the data is already 1's and 0's as per the original file held on the server at this stage. It is not pulses of electricity/light nor analogue waveforms at this point as neither of these can be held in RAM in their original state.

What this means is that when clocking out there are only 1's and 0's to clock out. There is nothing else. If you were saying these 1's and 0's are flipped or somehow distorted before they get to the RAM buffer that is a different matter. I don't think you are saying that at all though and clearly businesses etc would fail to operate if this were the case ie they consistently lost data points in digital transmission of data. The internet would not work either.

However, SPDIF jitter is commonly considered to be about timing not about the quality of what is transmitted. I think you agree as you refer to the transport clock. What I am trying to say here is I believe you are 100% correct in the theory but that it is a non-issue for any reasonably considered practical implementation. That it does not warrant special file servers or streamers. Sure if the streamer had 1k memory like a ZX81 and the DAC the same then fair enough but the RAM and clock out removes the worry of this time dimension in nearly all real circumstances one might imagine.

RF interference

I accept what you say on this. Not least because you know much more about it. Of course it is also a long-standing issue in audio not limited to reproduction of digital files.

Naim says it has electrically isolated the DSP front-end from the DAC. Understand this is through galvanic isolation / separation of power supplies. I am sure it has. Whether this is 100% foolproof or not is open to question. My guess is that even if it were, other sources of RF interference may interact with the DAC stage post DSP anyway (radiated rather than conducted perhaps). Whilst also RF interference, if it exists it is really a separate issue to the purity of the FLAC to DAC chain subject to external influence. However, RF interference is relevant for any audio kit and you have recommended good measures to mitigate if it is perceived to be an issue.

Servers and connection to streamer or DAC

Going back to server to streamer connections for a moment....for the purpose of debate lets say a FLAC file is 40MB in size for 4 mins of music. On my internet connection this would take approx 4 seconds to download and on home ethernet a little less time to transmit from point-to-point. In theory a quite basic streamer can receive all 4 mins of music almost instantly from a file server and hold it all in memory. I think too much is made of the server and its connection to the streamer. Providing the disk I/O, memory and ethernet connection are decent (not exactly rocket science) there is nothing much of interest in this end of the chain.

Finally...

What does all this add up to? Well IMO it implies that dealing with RF interference (if it exists) is more important than worrying about jitter when using NDAC or other DACs which use the same or similar approaches. The RF interference may not come from the FLAC to DAC chain.

I've always wonderd why, if RF chokes make an improvement, Naim don't fit them as standard?

Makes me think about those magnets you clamped around car fuel lines which were supposed to improve MPG.

Jason,

You have a number of choices when hooking up the US.  If you have no ND5x, connect it with either optical or coax to a DAC of your choice.  Then, connect the US to your network, if you want your rips to download track and album info from the Web.  Connect the DAC to your pre with an analog cable of your choice.

You could replace the DAC with an ND5x, and use its on board DAC in exactly the same way, bypassing its on board streamer, streaming from the US.  But it is more typical to retire the SPDIF from the US and rely on the network to SERVE music via your network to the ND5x and let it do the streaming, as it was born to do.  Then use an analog DIN from the ND5x to your pre.  

Some then add a better DAC between the ND5x and pre, using either optical or coax from the ND to the new DAC, bypassing the DAC on board the ND.

The digital inputs are on the ND5x to give other components, like a DVD player, the ability to play through the ND's DAC, if you want to.

Nick

As a follow-up, any reason why relatively inexpensive ferrite cores aren't good enough?  I can readily find them ~ $4.00 each and designed to clamp around cables of specific geometries (some designed for CAT5, others for round cables of various diameters).

No reason at all.

My Samsung TV came with a couple rf chokes.