NDX and Chord Hugo

Posted by: Foxman50 on 18 April 2014

I have been contemplating adding a DAC to my NDX/XPS2 to see (or should that be hear) what it can bring to the party. And so thought it about time i made inroads into Having a few home demos. After looking around at products that are within my budget i came across the Chord Hugo DAC.

 

Although it is meant to be a portable headphone unit, it can be used as a full line level fixed DAC.

 

The dealer lent me a TQ black digital coax lead, which have twist grip plugs. This was required as the present batch of Hugo's have a case design fault that wont allow any decent cable to fit, soon to be rectified. Thankfully the TQ just manages to hang on to the coax port.

 

Once all connected and gone through the minimal setup procedure of the Hugo, what does the red LED mean again, i left it to warm up for half an hour.

 

Poured a beer and sat down for an evenings listening.

 

What was that, where did that come from, that's what that instrument is. OMG, as my little'n would say, Where is it getting all this detail from.

 

After spending last night and today with it, all i can say is that it has totally transformed my system from top to bottom. I never considered my NDX to be veiled or shut in, not even sure that's the correct terms. All i can say is its opened up the sound stage and space around instruments. Everything I've put through it has had my toes, feet and legs tapping away to the music.

 

Even putting the toe tapping, the resolution the clarity to one side, what its greatest achievement for me has been in making albums that I've had trouble listening too enjoyable now.

 

One added bonus is that it has made the XPS redundant. I cannot hear any difference with it in or out of the system.

 

While i thought a DAC may make a change in the degree of the jump from ND5 to NDX, i was not prepared for this. Anyone looking at adding a PSU to there NDX may want to check this unit out first.

 

For me this has to be the bargain of the year.

 

Posted on: 22 June 2014 by Marky Mark
Originally Posted by Kevin Richardson:
It is strange that Hugo owners are now expected to provide peer reviewed journal citations to justify their personal experiences.

If you read the thread you will see we are discussing a claim of what amounts to a quantum leap forward in music reproduction which has been propagated in several places including this forum. This is what we're discussing. It has nothing to do with owners justifying their personal experiences.

 

Surely you would agree consumers are allowed to discuss new product claims? It seems odd that people seek to silence this (and is a recurrent theme on this thread for some reason). I can only assume it is because owners seek affirmation of their choice from others. If you are so sure of the rightness of your own experiences as you seem to suggest, why are you even reading this thread? Your decision is made so what else do you need??

Posted on: 22 June 2014 by Simon-in-Suffolk
Originally Posted by Marky Mark:

Alan, do you feel it is possible to perfectly recover timings to a sensitivity of 4 microseconds from a CD with samples at 22 microseconds of frequency?

I certainly don't, and if it was possible like, fitting a quart in a pint pot, I'd love to know how to.. It would certainly help me with at least one major digital voice  design project I am working on currently. An effective almost 3 to 1 improvement of data bandwidth to audio information with no loss of info would be very useful.. Mind you I suspect such a technique would be quickly patented if it existed...

Simon

Posted on: 22 June 2014 by Foxman50
Originally Posted by Marky Mark:
Originally Posted by alan33:
I don't know if this helps or hinders the dialog,

Alan, do you feel it is possible to perfectly recover timings to a sensitivity of 4 microseconds from a CD with samples at 22 microseconds of frequency?

Mark

 

has anyone on this thread said Hugo can perfectly recover this. If they have said perfectly then i believe you are quite right to question this claim. However i dont recal this term being used.

 

Graeme

Posted on: 22 June 2014 by KRM

Hi Kevin,

 

I think there are a number of reasons for the reluctance to test is:

 

- many are interested, but have already invested heavily and hadn't planned to spend again;

- loyalty to Naim, in the sense that it has always provided class leading products which suite their audio tastes;

- loyalty to their Naim dealer, many of whom don't sell Chord (me included);

- the apparent fiddlyness of a portable product;

- they need a digital hub, which the Hugo isn't;

- sceptisicm;

- fixated on how it works rather than how it sounds;

- even if it is true what's the catch?

- finally, if I try, I'll want to buy, and I don't want to buy so best not to know ( a bit like the 1st one);

 

Some, but not all of these apply to me, although I don't care how it works except in the sense that it might be the first of a new generation of DACs which mean we can look forward to getting more for less (A little hard to take if you're an NDS owner :-/ )

 

Please let me know if I've missed anything.

 

Keith

 

Posted on: 22 June 2014 by Marky Mark
Originally Posted by alan33:

 

In in the simplest implementation of digital to analog conversion, higher sampling rate and greater bit depth produce output waveforms that get progressively closer to the original signal waveform. There is a lot to be gained if you can go back and re-sample. There is also much to be gained, for any given digitized sample waveform, by being less naive, or rather more clever, when choosing your conversion algorithm. 
Seems most of us agree on this.

 

The most important and, in this discussion, overlooked part of the story on analog waveform recovery from a discretely digitized sample, however, is the fact that we need to end up with a continuous signal: no "instantaneous jumps" in either X (time) or Y (amplitude). Many people immediately grasp that a simple "linear interpolation" - ie drawing the diagonal straight line between two adjacent points, rather than the horizontal and vertical lines in the step-wise graph - often looks "closer" to the original analog waveform. It also happens, however, that drawing the curved line between two adjacent points defined by the higher order polynomial that goes through some additional points, both before and after our two points themselves, is often an even better reconstruction. You could solve for the parabola from three points (our two and the next one, for example) or the cubic from four points (our two and one on each side), or whatever you wish. This can also be used for "smoothing" discrete sets of points, but here we're thinking of adding extra information in BOTH the X and Y (time and amplitude) axes. It turns out, and you can see it in the sample photos in the PDF lecture notes, that you really can do a better job of image (or audio) reconstruction than the simplistic step-wise approach. You don't have absolute knowledge - ie you are not getting information back that you threw away on sampling - but if the data conform to your assumption (in this case that the signal has a smoothly varying behaviour), then the pencil line your arithmetic draws from the dots you sampled really is closer to the original line on the piece of paper that you threw away. If it's random data, you cannot win; if it's not, you can at least improve ... We are re-using data: we use four sampled points to join the middle two (1,2,3,4 to join 2 and 3, say), and we use three again plus the next one to join the next pair (2,3,4,5 to join 3 and 4, say). The new information is our assumption as built into our arithmetic (equation) model. If you were doing this by hand, drawing a curve freehand through the sampled points as someone suggested, it would be equivalent to looking at earlier and later points to infer the "most likely" way to join the line to the next point smoothly and continuously. 

Imagine all would agree there are different ways to interpolate. However, none deliver the 4 microsecond timing accuracy claimed to be needed and delivered given a 22 microsecond step on the x-axis. You acknowledge this above as you talk about approximations.

 

Also recall that there is not just one sine wave but a combination of sine waves. This will compound the deviations from the original analogue signal. Consider not just continuity of signals in interpolation but the accuracy in timing of starts and stops.

Posted on: 22 June 2014 by Marky Mark
Originally Posted by Simon-in-Suffolk:
Originally Posted by Marky Mark:

Alan, do you feel it is possible to perfectly recover timings to a sensitivity of 4 microseconds from a CD with samples at 22 microseconds of frequency?

I certainly don't, and if it was possible like, fitting a quart in a pint pot, I'd love to know how to.. It would certainly help me with at least one major digital voice  design project I am working on currently. An effective almost 3 to 1 improvement of data bandwidth to audio information with no loss of info would be very useful.. Mind you I suspect such a technique would be quickly patented if it existed...

Simon

Would be a nice patent to have

Posted on: 22 June 2014 by Marky Mark
Originally Posted by Foxman50:
Originally Posted by Marky Mark:
Originally Posted by alan33:
I don't know if this helps or hinders the dialog,

Alan, do you feel it is possible to perfectly recover timings to a sensitivity of 4 microseconds from a CD with samples at 22 microseconds of frequency?

Mark

 

has anyone on this thread said Hugo can perfectly recover this. If they have said perfectly then i believe you are quite right to question this claim. However i dont recal this term being used.

 

Graeme

Graeme, below is the quote from some mag that has been referenced. Also recall perfection was claimed or reported to be claimed before by some posters. Possibly in the posts now deleted by the admin, I haven't checked.

 

"the brain samples sound in real time every 4 micro-seconds, whereas CD refreshes its 'frames' every 22 micro-seconds. It's CD's inability to work as fast as the brain that causes its problems in the time domain, why it doesn't sound natural. And the unique design of the Hugo DAC addresses precisely this failing."

 

Alan, do you feel it is possible to perfectly recover timings to a sensitivity of 4 microseconds from a CD with samples at 22 microseconds of frequency?

Posted on: 22 June 2014 by Marky Mark
Originally Posted by Jan-Erik Nordoen:
an infinite number of taps would permit perfect reconstruction of the signal

Graeme, further to your question just one example.

Posted on: 22 June 2014 by Marky Mark
Originally Posted by Jan-Erik Nordoen:

from Rob Watts (on the HeadFi forum) :

 

1. The interpolation filter is key to recreating the amplitude and timing of the original recording. We know the ear/brain can resolve 4uS of timing - that is 250 kHz sampling rate. To recreate the original timing and amplitude perfectly, you need infinite tap lengths FIR filters. That is a mathematical certainty. Hugo has the largest tap length by far of any other production DAC available at any price.

Posted on: 22 June 2014 by lovethatsound
That's right marky mark, that's why you should go out and buy one, and give your brain cells a rest.let you're ears do the talking.
Posted on: 22 June 2014 by Big Bill
Originally Posted by Simon-in-Suffolk:

Guys, I am not sure what interpolation has to do with what we are talking about. For over sampling interpolation is horrendous as loads of false frequencies are created, hence why usually when over sampling zero samples are used, as no erroneous frequencies are therefore created making filtering a lot easier to perform. Zero multiplied by anything is always zero.

Simon

I think we were both (me and mark) answering a post by Jan.

 

btw in your post I assume you were referring to aliasing?  Aliasing will occur without over-sampling, it's simple a set of points that can fit a frequency or an overtone of that frequency.

 

The point I was trying to make is that the samples are a reality they are not calculated points and they are approximations - they are Integers where a Real number is what is needed.  We never mentioned timing errors either, so if you imagine a sample on an x-y plane it is an area on 'uncertainty' on this plane.

 

Your point about the work Kunchur (and others) was fascinating in they way he related it to the 'Uncertainty Principle' - although quick to distance it from the 'intrinsic' nature of Mrs Heisenberg's son Werner.  But later workers found examples that broke it!  I nearly had a heart attack until I read it properly!

Posted on: 22 June 2014 by Big Bill
Originally Posted by fatcat:
Originally Posted by Marky Mark:
 

In case it remains unclear to anyone, lets do this. Take a pencil and draw a line on one page. Next trace two dots marking the beginning and end of that line on another page. Now throw away the first page. Next, draw a line joining the two dots on the second page. That is interpolation. You are using one method which estimates points between the end-points. Is it exactly the same to the millimetre as the line on the first page? No, it is not, unless by some random coincidence. You can't even check it because you don't have the first page any more.

 

Mark

I don’t think you fully undersatand the term interpolation.

Take a piece of A4 graph paper and ask somebody to draw a sine wave freehand. Record values of y every 5mm along the x axis, keep the graph paper, do not throw it away.
Plot the recorded values on two pieces of graph paper. Take the first plot and join the the dots with a rule, IE straight lines, take the second plot and join the dots freehand producing a curved wave.

Compare both with original, which is more accurate, the first or second.

But they might draw an alias and as I keep saying in digital music these sample will not be accurate.

Posted on: 22 June 2014 by Foxman50

Mark

 

these are snippets as you say from a mag and by the designer i believe. My point is although i understand where you are coming from, i don't think anyone here can answer your questions regardless of how many times you ask them.

 

It doesn't bother me you asking them, i just feel nothing is getting resolved. The question you ask does indeed sound to me to be wrong. How can anything be reconstructed if it is not there to start with, this goes for anything in life.

 

All i can add is let the hype and marketing babble say what it likes, if it sounds as good as it sounds, who cares. I for one do not.

 

Graeme

 

 

Posted on: 22 June 2014 by GraemeH
Originally Posted by Wat:
Originally Posted by KRM:

Hi Kevin,

 

I think there are a number of reasons for the reluctance to test is:

 

- many are interested, but have already invested heavily and hadn't planned to spend again;

- loyalty to Naim, in the sense that it has always provided class leading products which suite their audio tastes;

- loyalty to their Naim dealer, many of whom don't sell Chord (me included);

- the apparent fiddlyness of a portable product;

- they need a digital hub, which the Hugo isn't;

- sceptisicm;

- fixated on how it works rather than how it sounds;

- even if it is true what's the catch?

- finally, if I try, I'll want to buy, and I don't want to buy so best not to know ( a bit like the 1st one);

 

Some, but not all of these apply to me, although I don't care how it works except in the sense that it might be the first of a new generation of DACs which mean we can look forward to getting more for less (A little hard to take if you're an NDS owner :-/ )

 

Please let me know if I've missed anything.

 

Keith

 

Another excellent post. My take is it is not Naim's fault if somebody makes a better DAC. My Naim kit has given me great service and i have thoroughly enjoyed using it; that i can now get more for less is great. I can choose to change or wait or stick (nothing anybody has sounds worse because of the next generation). Recent developments at Naim (focalisation and beyond) has meant that change was no longer an unpalatable option. Seems Naim is more likely to concentrate on whole house multi-room systems than the Mother of all DACs at an affordable price (this conjecture may be way off the mark, but with no product roadmap it is all a matter of interpolation: my view changes every 4 microseconds, of course). 

 

All the best, Wat 

Very astute Keith.

 

I would also add that the naysayers who have not heard this dac are now somewhat cornered as they have forfeited the capacity to hold a received opinion. They can neither come out in favour if they do hear it, nor appear to dislike it if they do hear it. The former they now look foolish, the latter they look churlish.

 

G

Posted on: 22 June 2014 by Adam Meredith
Originally Posted by GraemeH:
I would also add that the naysayers who have not heard this dac are now somewhat cornered as they have forfeited the capacity to hold a received opinion. They can neither come out in favour if they do hear it, nor appear to dislike it if they do hear it. The former they now look foolish, the latter they look churlish.

"High on top of a mountain there stood an old bull and a young bull.

Both of them were leering at the young heifers down in the valley quite a distance away.

The young bull was snorting, huffing and puffing, pacing back and forth, etc.

Finally, after a while, the young bull said...

"Say, why don't we run down this mountain and have our way with one of them?"

The old bull pondered for a moment, smiled, leaned over, and calmly said...

"Why don't we walk down the mountain and have our way with all of them!" "

Some people may like to take their time over decisions and not run after every first thing another bunch of people got a boner over.

 

If this really is the Second Coming there is a good chance that there will soon be a more convenient iteration and, with luck, less hideous - unless it too comes from Chord.

 

For the record I don't own a DAC.

Posted on: 22 June 2014 by Aleg
Originally Posted by Marky Mark:
Originally Posted by Foxman50:
Mark

 

has anyone on this thread said Hugo can perfectly recover this. If they have said perfectly then i believe you are quite right to question this claim. However i dont recal this term being used.

 

Graeme

Graeme, below is the quote from some mag that has been referenced. Also recall perfection was claimed or reported to be claimed before by some posters. Possibly in the posts now deleted by the admin, I haven't checked.

 

"the brain samples sound in real time every 4 micro-seconds, whereas CD refreshes its 'frames' every 22 micro-seconds. It's CD's inability to work as fast as the brain that causes its problems in the time domain, why it doesn't sound natural. And the unique design of the Hugo DAC addresses precisely this failing."

 

Alan, do you feel it is possible to perfectly recover timings to a sensitivity of 4 microseconds from a CD with samples at 22 microseconds of frequency?

I don't read into this that the perfect reconstruction by the Hugo has to be done from the CD sample rate, it just says the CD (player DAC) isn't capable of doing this perfect reconstruction (probably due to both sample rate and reconstruction filter).

Posted on: 22 June 2014 by Big Bill
Originally Posted by Adam Meredith:
Originally Posted by GraemeH:
I would also add that the naysayers who have not heard this dac are now somewhat cornered as they have forfeited the capacity to hold a received opinion. They can neither come out in favour if they do hear it, nor appear to dislike it if they do hear it. The former they now look foolish, the latter they look churlish.

"High on top of a mountain there stood an old bull and a young bull.

Both of them were leering at the young heifers down in the valley quite a distance away.

The young bull was snorting, huffing and puffing, pacing back and forth, etc.

Finally, after a while, the young bull said...

"Say, why don't we run down this mountain and have our way with one of them?"

The old bull pondered for a moment, smiled, leaned over, and calmly said...

"Why don't we walk down the mountain and have our way with all of them!" "

Some people may like to take their time over decisions and not run after every first thing another bunch of people got a boner over.

 

If this really is the Second Coming there is a good chance that there will soon be a more convenient iteration and, with luck, less hideous - unless it too comes from Chord.

 

For the record I don't own a DAC.

Adam you sound like a man of great wisdom.

Posted on: 22 June 2014 by alan33
Originally Posted by Marky Mark:
Originally Posted by alan33:
I don't know if this helps or hinders the dialog,

Alan, do you feel it is possible to perfectly recover timings to a sensitivity of 4 microseconds from a CD with samples at 22 microseconds of frequency?

You're asking two questions - one about accuracy ("perfectly") and one about improvements ("recovery").

 

As I said, you can't know with certainty more than is in there, so you can't guarantee perfection...but you can easily imagine a factor of five improvement over raw data (so aiming at nice signals with a 4 microsecond granularity from a base sample rate of 22 microseconds). 

 

Given the much higher resolution (bit-depth) of the output converter (ie voltages can be driven with much finer step sizes than they were sampled at) and the much higher clock rate of the electronics (I don't know what it is, but MHz is easy for FPGA driven output stages and GHz is possible for the data management and computation), I'd go with "yes, that's the scale they are designing to". The people who have heard this unit are pleased, the base technology supports this approach, it sounds good to them,  etc. I don't really know if the 4 microsecond target is meaningful for human brains.

 

I do know that you can exceed classical optical signal limits using similar techniques - beating the diffraction limit or eliminating time varying noise sources using a theoretical "adaptive ideal calibration" technique. Audio, as a signal, is easier than this sort of stuff...lower frequencies, one dimensional, slmaller dynamic range, lowner slew rates, etc. think of how much improvement you can make to photos from even the simplest image processing software. Then, for those who think "source first" think of how much harder it is to improve the focus, not just the granularity or resolution...there are limits, but they aren't intuitively obvious and shouldn't impede conversations about what we enjoy, what we prefer, or whatever!

 

Regards, alan 

 

ps - I replied before reading all the other posts, sigh! I don't know what overall improvement vs a naive implementation they claim, but there is obviously something large. I also see that some folk point out that one way to read their output spec is in reference to its ability to handle higher resolution input signals...and this is a far more achievable way to get better output, by starting with better input! Apologies for the quick trigger finger...it's early and I'm off soon to ride my bike!!

 

pps - Thanks also for kind replies, I'm glad the long post wasn't a waste of everyone's time. 

Posted on: 22 June 2014 by Simon-in-Suffolk
Originally Posted by Adam Meredith:

I attach a photo of myself to prove our distinct identities and put to rest, for ever, these calumnies.

 

Bill, he certainly is.

 

Simon

Posted on: 22 June 2014 by George J

Something about the stereo illusion - the impression of directionality across a width - from two point source speakers. 

 

When AD Blumlein was conceiving and implementing binaural two track recording in the years up to 1934 when the first disks were actually made, he was keen to keep the ability of the recordings to be mono-compatible. This is to say that when the two channels are summed a perfect mono recording results - without comb-filtering, caused by time delay phasing variably affecting the amplitude of different pitches of notes [frequencies of the signal] in the two channel recording to be summed.

 

His stereo replay was based on the premise that the amplitude of the signals sent into the two loudspeakers used for replay will give the impression of directionality in the replayed recording. This was managed by the use of a crossed pair of microphones placed so close together as to prevent phase difference, but only create [in the two channels recorded] differences of volume according to the direction from the microphones to the instruments and singers [or for for film other sounds] to create the illusion of actual directionality.

 

Though the human ear can often place a sonic event in real life [such a breaking twig in the forest] with startling accuracy using phase difference to the two ears, this is not the method used for normal stereo recordings except in the case of dummy head style recording. Dummy head recording rarely works well for traditional stereo loudspeaker replay, but is magical for headphone listening.

 

I think the discussion here so far about the ability of the human ear-brain listening system misses this vital point about how stereo recordings are actually made and work in the real world. It seems that if this timing ability of the human ear was crucial then Blumlein's stereo system - still the basis for stereo recordings today - would never have worked!

 

It would have meant that stereo recordings would not have produced directionality on CD replay either. And that the distortions of the tracking angle of the stylus on a stereo vinyl recording [as it tracks across the side] would have produced mayhem in stereophonic terms.

 

ATB from George

 

 

 

Posted on: 22 June 2014 by Adam Meredith
Originally Posted by Simon-in-Suffolk:
Originally Posted by Adam Meredith:

I attach a photo of myself to prove our distinct identities and put to rest, for ever, these calumnies.

 

Bill, he certainly is.

 

Simon

 

In the Same Room - together.

 

Posted on: 22 June 2014 by GraemeH

Listen to the guy on the right.

 

G

Posted on: 22 June 2014 by Hmack

"High on top of a mountain there stood an old bull and a young bull............."

Excellent post Adam, and you make a very valid point. In fact one of the very first truly logical arguments in respect of sticking to the status quo (whatever happened to them?).

 

My own reason for purchasing a Hugo wasn't because I believed it heralds a '2nd coming', nor was it because I crave the latest and best fad out there. Just take a look at my profile and the hi-fi kit I use. It will be plain to see that this is not the case.

 

For anyone who owns a top-of-the range Naim, Linn or any one of a number of other high quality streamers or CD players, there is no need to go down an alternative route. I still like my Klimax Renew very much even if it has almost certainly been bettered by the Hugo in my other system. 

 

However, for those who were or are not quite satisfied by the performance of their existing kit (in my case an ND5 SX - good but just not absolutely right in my system), auditioning the Hugo seemed like a very sensible thing to do. For those whose interest is engaged by this thread or by the many good reviews of the product, then it's your choice, it won't cost you a fortune and there will be a ready second hand market if you decide it's not for you. This has always been the way with hi-fi equipment.

 

If another better product comes along in the next 6 months or so (from Naim or another manufacturer), then congratulations for holding off till then and good luck. I certainly won't be envious (this is probably a lie!), or more truthfully I'm happy with what I've got now, and won't feel the need to upgrade further.

 

I do take your point about the looks of the Hugo and Chord equipment in general - a bit of an acquired taste.       

 

 

Posted on: 22 June 2014 by Hmack

"For the record I don't own a DAC".

 

Adam, I'll bet you do own a DAC of sorts somewhere - Maybe not one that you have paid a lot of money for. Do you have an IPAD, IPod, mobile phone, CD player in your car, small portable DAB radio?

Posted on: 22 June 2014 by Big Bill
Originally Posted by Hmack:

"For the record I don't own a DAC".

 

Adam, I'll bet you do own a DAC of sorts somewhere - Maybe not one that you have paid a lot of money for. Do you have an IPAD, IPod, mobile phone, CD player in your car, small portable DAB radio?

Hmack don't start me off on DAB radio.  Why on Earth did NAIM put one in the Unitis .......... blah ....... blah ..... BBC idiots ....... blah ....... Tony Blackburn ....... blah ....... David Cameron ....... blah

 

Too late you have done it now.