We say source first, but what counts as a source?

In the beginning and in the end is the DAC. The remote source of the music is getting less relevant, just as long as it has enough bandwidth to deliver it to the DAC. The DAC is where the musical translation occurs and how it is then amplified, isolated and reproduced reflects the quality of your HiFi. The only Naim equipment I own is a Muso and I rely on Spotify for streaming. As I have an Onkyo AV amp for my HD television viewing, I drive my old Castle Harlech speakers with this as well as PMCs and Monitor Audio sub for the surround sound aspect. The Harlechs are bi-wired and bi-amped but had not used them as HiFi much since getting the Muso. However, this morning I was in the sitting room and connected my iPhone via Apple TV and Spotify to the (high end) Onkyo and was very pleasantly surprised at the clarity, depth, separation and precision of the musical delivery. I know the Muso is 'just' a music centre but the Onkyo and 18 year old Harlechs, albeit on their second set of drivers, had it for breakfast. They both receive the same signal so it has to be a combination of DAC, amplification and speakers. Obviously original recording quality is integral as well. I guess I'll  press pause on the Statements, Lumina Cables and Focal Grande Utopias for the moment. A pleasant way to spend Easter while the roast lamb cooks slowly and just before heading off to the pub.   

The quality of the source these days is very high.  Digital ensures perfect delivery and then it's down to your DAC and the standard of DAC's is very high across the board.

The thing people should be looking at these days is speakers as that's where the big difference in sound is.

The pre-Dac part of the chain is critical too. Having just moved from NDX/Hugo to Sonos Connect/W4s Reclocker/Hugo the reclocking is vital to de-jitter the signal feed to the dac. Sounds poor without it but (I'm discovering this weekend) NDX beating with it In chain.

A bit untidy as a 'three box or four with NAS' collection of components but it sounds waaaay bettter than it should for the (relatively) modest outlay.

Source first in quality but not price these days - ime.

G

Absolutely.

How many times in the past did we read, "The dacs have the same Burr-Brown chips so they should sound the same," and we know that's a fallacy.  It's not just the chips, it's not just the dacs.  And to me, stringing together 4 pieces of hardware . . . just leaves all that much more room for something to be 'off.'

Pre-dac digital accuracy is critical, yes, no question.  However, timing jitter aside just for the moment, there are only two ways that part of the chain can perform, i.e correctly, or incorrectly.  There is only one desired outcome, and it should be achievable from a variety of options.  

Question on the re-clocking of the Sonos, and I don't know if the Hugo does the same, but there is some Naim blurb for the DAC-V1, which makes quite a point about it's buffering and re-clocking capabilities, claiming they will eliminate incoming timing jitter.  Does that negate the need for another re-clocking device?   I had assumed the external reclocking would be beneficial only to DACs that do not re-clock themselves.

Certainly appreciate your point about the DAC chip, a TI PCM1791A (as found in a DAC-V1) costs under $4 I believe, so you'd hope there was something more to making them work effectively in DACs costing thousands.  

Nope, you are just plain wrong! You cannot contaminate bitstreams without destroying the input to the DAC. The DAC defines the potential music you will hear.

These discussions seem to always boil down to the "bits are bits" arguments.  We've been here before.

In terms of UPnP servers that deliver subtly different raw bitstreams, I do see this as entirely possible.  It's a little different, but I have done several test using the WAV files supplied by Naim for testing bit perfect delivery to the DAC-V1, using Jriver, Foobar, Xplay, XBMC (now Kodi I believe) and a creation of my own.  Jriver and Foobar pass the tests at any sample rate, provided the bit-depth matches that set in the Windows control panel.  Not sure why, as my own player (using WASAPI exclusive mode) is able to change between them, and pass the test at any bit-depth or sample rate.  Clever me?  Not really.  XBMC however, even with everything turned off in terms of digital wizardary and also using WASAPI exclusive never passes any of them.  So, it's doing something to the bitstrream.  There is not contamination of the bitstream XBMC rendered, but certainly contamination still, as the bitstream is different to the original.  And yes, this is audible, and no I haven't done any blind test.  If some UPnP software does the same, possibly quite deliberately because someone though it a good idea and improved things, well the result might be similar.

Do you have a point, or do you just not like the answer? You are sounding just like politicians who do not like a contrarian position to their politically correct assumptions? If you assume that "bits are bits" is a satisfactory put down then why bother responding at all and not just continue quietly to blow good money after bad on your prejudices? We are not talking of an LP12 with an Itok arm and whatever cartridge all influencing the end result, I am sorry to say to you that a "bit is a bit" and if it does not total up from one end to the other you will simply hear nothing. Now, the DAC and further forward, that is something completely different. Still, if you want to spend five or six grand on a pimped NAS, then help yourself.

I think that inadvertently you have arrived at the answer. All of these bits of software massage the output of the bitstream and present you with their own "solution" which, strangely, is exactly what a DAC does. Why do we gave so many flavours of DACs? The bitstream does not change. 

I was surprised to find that a Chord USB Silver Plus improved the sound of my DAC-V1 (via Foobar2000). I had assumed that with it being async, that the USB cable wouldn't matter, however when I reverted back to a stock Belkin, the sound definitely seemed flatter in comparison.

Inadvertently?  Nothing accidental about it.  I agree, the DACs do all kinds of digital processing, filtering, and up-sampling.  Personally, I am happy to leave that in the hands of high-end audio manufacturers, and would therefore rather that PC software stayed out of that.  And in the right configuration, and with the right software, it does. I don't actually use UPnP, so I can't say too much about that; my NAS is simply a file share visible to the 'hifi' PC. 

My apologies. Was just going to add that what exactly differentiates a Chord Hugo from any other headphone amp?

Mmm, I was surprised by that too, though I bought a Furutech Formula 2, but previously had a Belkin.  I have no explanation for why though, it makes little sense.  I do understand something of the differences between the isochronous transfer used for USB audio, and the bulk transfer mode used for a printer for example.  The key difference is the time critical element, and lack of retry option when used in isochronous mode, as is the case for audio, whether asynchronous, or otherwise.  As digital audio via an electrical cable is not simply a case of 1 or 0, this is interpreted according to voltage variations and thresholds.   Therefore, it could well be that a substandard, or damaged cable, count lead to more frequent misinterpretations.  However, if the DAC-V1 bit-perfect tests are to be believed, both the Belkin cables and the Furutech passed them fine.  So, is this all in our heads?

No worries.  The Hugo does appear to use significantly different technology within the DAC chip itself, versus the huge amount of TI Burr Brown DACs out there.  I've always felt that it's more about the analogue stage in most really exceptional CD players, and even more so with streamers, and DACs.  The Hugo is different again to me, as so much of what it does, is achieved in the digital domain.  I've not heard one, and it is clearly not for everyone, but the amount of praise it gets suggests it must be doing something very right 

100%.  Am fascinated by the hype surrounding the Devialet Phantom and its mix of analogue and digital amplification to smooth the received signal  but have yet to actually see a satisfactory critique of the product outside of the exhibitions. 

I think your barking up the wrong tree if you think information is being lost or corrupted between a streamer and DAC. Whether SPDIF coax, SPDIF optical or USB, the correct information is transmitted, the sound degradation is caused by noise transmitted through the cable from the streamer or noise picked up by the cable from external sources.

+1 uptick.

Makes you wonder doesn't it. Both cables passed the bit perfect test for me as well. I suppose you've just got to go with your ears. Either way I felt that the £40 spent on the USB cable was well worth the outlay in the context of my system

 It could be either, don't you think?  I've had experiences with useless USB cables in the non-audio world.  You can attach a dodgy (and I mean damaged here..I think) USB cable between a PC and a hand-held device, and they'll recognise each others existence, no problem.  Start transferring heavy amounts of data in this scenario though, and it very quickly falls apart, and in a number of instances, the only remedy has been to replace the cable.  However, despite this view, I would not expect such a failing in a cable to reveal itself in a hifi characteristic such as sounding flat, for example, or for a superior cable to offer greater openness and bass depth etc.  Generally speaking, I've found failings in digital audio, for whatever reason, to be manifested in pops and clicks, gaping pauses...that type of thing. 

Then there is the example of an evening with a friends Arcam IRDac.  It performed fine in quiet passages of music, but when things got louder, it began to break up.  I got up and moved the cable around in the back of the DAC, and provoked this noise, and then after wedging it in a suitable position, everything was fine for the rest of the evening.  

Digital cables do not just work, or not.  The question is, and I remain open minded, do they really affect sound quality in the hifi sense, or do they just very obviously fail when there are issues.

Too right. As I always say, it's better to be safe.

Clearly there are differences between DAC's, but I have for some time wondered how much these are due to the DAC chip or equivalent and how much is due to the processing ex DAC and presented to the amp/preamp. It is, I would think, quite easy for the unit to apply some level of equalisation which will affect the sonic signature and the apparent level of detail. This can have a geater effect than the wirk of the digital conversion itself, and will present the information to the amp in a way thought best by the designer.

Of course,effective isolation from electrical interference etc will also have an effect.

There was a very interesting recent piece by Michael Lavorgna in Audiostream magazine on the topic of "bits are bits" vs cables.

His argument boils down to saying that unless something is truly broken, bits will always reach their destination intact and unchanged, but (as someone mentioned above) the cable may carry with it or even introduce noise, and this affects the audio as we hear it.  Better cables have better screening and noise rejection, so we may detect a subjective improvement in their sound.  This would apply to all connections including LAN cables, thus explaining why some folks hear benefits from exotica such as Audioquest Vodka.

This makes sense to me, though for my part I'm very happy with Grey Goose.....  ;-)

It's interesting that this thread suddenly became the ol' "bits are bits" chestnut again. But it also shows some common misconceptions and a lot of jumpting to conclusions based on incomplete understanding. As an senior IT specialist for a major blue chip IT company, I cannot deny that bits are bits because I know this to be true, and empiracally provable. There is no such thing as a better quality bit.

But, I also know there is more engineering behind how these bits are conveyed and the different issues that arise. So while bits may be bits, it is only the first chapter in a longer complex story.

Optical Cabling.

Longer runs of optical cable (generally longer than 8-10m) will be susceptable to attenuation of the red spectrum used in the communication. This can result in stray bits but is unlikely in the length or runs used for home audio. Shorter runs of optical medium with minor occlusions can also cause this. Not a major issue with IP over optical since the packets are verifies and resent as required. Audio on the other hand must accept a linear non negotiated stream. Still, the main issue here for sub 24/96Khz streams isn't the bits (which should be perfect in most cases) but jitter and microphonic vibrations. Most Naim units reclock input to reduce jitter to near zero (near because this has to happen after the Toslink receiving unit which operates within defined frequencies). Better cables reduce vibrations similar to how Naim's airplug works - the optical medium floats inside a much larger outer sheath and if possible, terminating ends of the cable are decoupled from the centre optical medium. Vibrations do not affect bits but they do affect analog circuits in the DAC. The most delicate being the first stage analog output before pre amplification brings the signal up to line level.

Coaxial cabling

Similar to optical, on short enough runs it is capable of bit perfect transfer but to higher data rates than the Toslink Audio specification. Red spectruim attenuation obviously is not applicable and neither is any artifice or additional non digital noise caused by the conversion of light pulse to electrical signal. Generally preferred as a superior carrier to Toslink (open to debate - I don't want to get into that here) but is subject to RF interference. RF interference is generally not enough to change a bitstream so again, should be bit perfect. But it does introduce the same microphonic vibration issue and can now carry RF interfernce picked up outside the unit to inside the unit to be picked up by any suceptable analog circuits. Generally microphonics are mitigated by virtue of a heavier cable to dampen any affect and suitable screening for the RF.

Network cabling

Since ethernet transmissions are both controlled, validated, resent, and sequenced, there should never be any impact on the payload. Missing data packets or packets with failed checksums are going to be re-requested by the receiving end as part of the protocol. So from cheapest to most expensive cable, the payload will not change and packet sniffing proves this. But they introduce the same problems of RF interference and microphonic vibrations as any other non optical cable which can affect analogue circuits. Therefore moderate care in choosing a sturdy well screened network cable will yield some improvements - there is no need to go crazy though - some expensive LAN cables are pure snake oil.

What does affect data integrity for networks more than anything is network configuration and the quality of switches and routers. Poor configuration can lead to delayed packets or frequent retransmissions. Ditto for the hardware. Older or cheaper components may only support half duplex (send or receive but not sumultaneous send+receive) and mismatches in port configrations (generally domestic usage network components allow no user configuration) between any two components can lead to packet collisions. The good news is that that the data either arrives there complete (bit perfect) or not at all. The bad news is that it can arrive late or out of sequence generating alot of overhead for the receiving unit.

UPnP

As has been discussed elsware on the forum, fed with identical audio files, these can yield different results. Whether they do or do not transcode obvious totally changes the stream (since the formats transferred to the streamer could be dotally different). Even with direct wav data, some change the stream to apply preset recording level normalisation or add (or artificially remove) dynamic range compression by applying transformations directly to the digital stream. If you want to ensure your bit is really a bit over UPnP you are going to need to trust that it faithfully transcodes unadultered data as it unpacks it from the file or passes the file as-is (but that offloads file unpacking to the streamer which has its own impact).

Digital out from PC

This is often not bit perfect which is exactly why the DACv1 comes with a utility to verity this. Cheaper soundcards may downsample streams and many applications at lease apply digital transformations to adjust the recording level so you can adjust volume from the PC. Some users on the forum have also state they use room correction software before sending out to the DAC so again, the stream is not going to exactly match the input file's bitstream.

For these reasons, the concept of "source" does not fundamentally change. Anything between your source audio data and the preamp is therefore the "source" of which the DAC is only one part.

IMNSHO.