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: 21 June 2014 by Foxman50
Originally Posted by Char Wallah:
Originally Posted by Foxman50:
Simon
Its quite funny really, i can only compare this with my daughter.
she will refuse to try some food because she gets it in her head that she wont like it. No matter how much ill sit there saying just try it you may like it, but if you don't try you wont know. Very frustrating when your just tying to help.
The main difference is she was 8.
Maybe that says it all
Graeme
I don't see why or how you can imply that the negative reactions to the endorsement of Hugo are a result of childishness. To me this mode of argumentation just casts even more veracity to the claims being made.
I'm sure Hugo is a nice product.
When negative reactions are made without any justification i indeed compare this to a childish illogical reaction.
Most adults grow out of following trends, flavour of the month items, following the crowd and start to make there own decisions based on ones own judgment after some research.
I made the analogy above because i feel some here are judging the product and other members without any justification or knowledge at all.
Have a demo and make an informed decision. Just don't criticise those that have.
Graeme
Posted on: 21 June 2014 by Marky Mark
Originally Posted by Simon-in-Suffolk:
MM, I have looked at this 4μS thing and looked at the various references... I suspect we might be talking about it out of context.. It appears nothing with the timing or decay of a sound or even frequency response.. It's all about the process within our brains for spatial positioning of sound, and the ability to differentiate between our ears... so as to detect the sound location.. I suspect an evolutionary trait that existed before speech.. and the brain apparently can differentiate the relative timing or phase difference between our ears down to 4μS.
Now the fun supposition part, perhaps its this ability in part of our brains in the world of hifi that allows us to enjoy two channel stereo and largely filter out the effect of room reflections so the sound comes front in front of us and not ricocheting from the side or behind us in terms of positionIng..
The inter aural things is interesting. Perhaps going forward music is best heard on head phones surrounded by predators in the jungle. 
However, there is no proof of the 4 microseconds thing. I read the Kunchur sumary from Dever and thought it flaky at best. From Yamaha "With a speed of sound of 340 meter per second, this distance constitutes a time delay difference for signals arriving from positions at the far left or right of the head (90-degree or -90-degree in figure 413) of plus and minus 618 microseconds." So, add in the reflections you note and 4 microseconds is soon confounded even if it were true.
The other big issue of course is that even if 4 microseconds was vital, the samples on the CD are only at 22 microseconds. 4 microsecond detail doesn't exist. Thererfore the only way you can introduce that level of detail is to synthesise it through guess work.
Posted on: 21 June 2014 by Marky Mark
Kunchur - comments on quotes from Dever's quoted article in a mag:
"he found considerable initial difficulty in trying to set up the test with digitally derived signals, as they were of insufficient ‘quality’ to achieve the required test sensitivity”
His solution? He gave up and used an analogue system to imitate the digitally derived sound. FAIL.
"instead an analog signal generator was used to produce a 7 kHz square waveform that had fast 20ns rise/fall times (a thousand times faster than the 23μs rise/fall times that characterize the 44.1kHz sampling rate of the digital compact disc”
The experiment involved imitating the waveform of CD samples. However, with oversampling and interpolation that is not what most devices output as analogue signals. FAIL.
"So in order to corroborate his first view about the inadequacy of most (if not all) consumer digital audio equipment standards, he has to go back to an analogue signal source”
He had a desired outcome before he tested. FAIL.
"the digital sampling rates used in consumer audio are insufficient for fully preserving transparency”
He is talking about hi-fi systems in isolation without the context of the source material. There is no transparency to fully preserve. FAIL.
Posted on: 21 June 2014 by Marky Mark
Originally Posted by Aleg:
Originally Posted by johnG:
Originally Posted by Simon-in-Suffolk:
MM, I have looked at this 4μS thing and looked at the various references... I suspect we might be talking about it out of context.. It appears nothing with the timing or decay of a sound or even frequency response.. It's all about the process within our brains for spatial positioning of sound, and the ability to differentiate between our ears... so as to detect the sound location.. I suspect an evolutionary trait that existed before speech.. and the brain apparently can differentiate the relative timing or phase difference between our ears down to 4μS.
I asked Rob Watts on the head-fi forum (chord hugo thread) a couple of hours ago about the 4 micro seconds and he was generous enough with his time to post a comprehensive reply in which he says that the timing he is talking about is the inter-aural delay as you say above. Well worth reading his explanation in full. Fascinating stuff.
Hi John
Thank you for putting the question to Rob Watts and for posting a reference to his reply.
That answer should clear up some confusion on the why question of high sample rates and the importance of timing.
It does not. Firstly, 4 microseconds is unproven. Secondly, even if it were proven, it is not cleanly applicable in a listening room with speakers in front of you and reflections. Thirdly, there is not 4 microseconds detail on the CD anyway so this is all hypothetical. Unless you have the analogue masters to hand?
Posted on: 21 June 2014 by Aleg
Originally Posted by Char Wallah:
I'm sorry, however, because of the investment you appear to have in Hugo you have quite overlooked the drift of my reason for posting. I have made up my mind as to the Hugo, I think it is a nice product. What I'm trying to explain is on this thread we are only hearing the same few voices endorsing the product. There has not been any similar comments from other members of this forum, to reinforce your opinions, which I find a bit strange if the Hugo is good as you claim it is. This isn't a criticism, just an observation. I will keep on eye on this thread to see if other members on the forum will find the same as you on listening to the Hugo. But because of the nature of the thread so far, I will remain unconvinced until a few more can confirm your claims. until then , keep enjoying the music.
Hi Char
I will add my voice to it then, as I have just done a Naim parts exhange which contains my Naim DAC + XPS-2, and for a DAC I now use the Cord Hugo.
Reason for me were the better clarity and detail of presentation, better timing giving better leading edges on notes and overall for me a somewhat increased punch to the sound.
Sound maintains a good amount of bass and has a very nice midrange as well and sounds lovely on vocals.
I think it is a very well balanced sound with all the benefits of a great timing.
Cheers
Posted on: 21 June 2014 by Big Bill
Originally Posted by Jan-Erik Nordoen:
Originally Posted by Marky Mark:
Thirdly, there is not 4 microseconds detail on the CD anyway so this is all hypothetical.
The detail can be reconstructed by interpolation. Nyquist theorem.
http://users.encs.concordia.ca.../slides/Sampling.pdf
See section "Reconstruction of a Signal from Its Samples: Interpolation"
Jan that article is theory and remember that the Nyquist Theorem is, as the name suggest, a theorem. It is a mathematical proof that in an ideal system the sampling frequency needs to be twice the highest frequency you wish reconstruct. This is done purely mathematically, I am sure you can find the maths somewhere it is an interesting proof. Please read it.
Now in the article you cite there are many diagrams that show samples fitting exactly into the reconstructed sine wave - perfect does it not look? But the samples the sine curves are being fitted to are an accurate sample of the analog waveform that was converted, that is an integral part of the theorem. However, in practical systems, the samples are only accurate with respect to the word length being used - 16 or 24 and become less accurate (as a %) for lower amplitudes. So the interpolation shown in paper you cite apply in theory, ie on paper but not in practice. So as Mark says you cannot accurately interpolate because you have no idea what the accurate answer should be.
Nyquist also does not have to deal with things like capacitance & inductance in circuits either.
Posted on: 21 June 2014 by Bert Schurink
Originally Posted by Simon-in-Suffolk:
Bert, what do you think you want to do? If curious then yes go ahead and have a listen, if you are not particularly curious , and / or you are happy with what you have there are probably better things to do.. Like listen to some of those recordings of yours..
Simon
Hi Simon, While I am not prepared to spent so much money anymore. I am always looking at ways of achieving perfection. So that's why I followed this thread with interests. However if it would be a side step it would never be interesting for me. As I am very happy with my current system.
And of course you are very welcome to come and have a listen at my collection whenever you pass the ocean and land in Germany.
Posted on: 21 June 2014 by DavidDever
Originally Posted by Marky Mark:
Originally Posted by Simon-in-Suffolk:
MM, I have looked at this 4μS thing and looked at the various references... I suspect we might be talking about it out of context.. It appears nothing with the timing or decay of a sound or even frequency response.. It's all about the process within our brains for spatial positioning of sound, and the ability to differentiate between our ears... so as to detect the sound location.. I suspect an evolutionary trait that existed before speech.. and the brain apparently can differentiate the relative timing or phase difference between our ears down to 4μS.
Now the fun supposition part, perhaps its this ability in part of our brains in the world of hifi that allows us to enjoy two channel stereo and largely filter out the effect of room reflections so the sound comes front in front of us and not ricocheting from the side or behind us in terms of positionIng..
The inter aural things is interesting. Perhaps going forward music is best heard on head phones surrounded by predators in the jungle.
However, there is no proof of the 4 microseconds thing. I read the Kunchur sumary from Dever and thought it flaky at best. From Yamaha "With a speed of sound of 340 meter per second, this distance constitutes a time delay difference for signals arriving from positions at the far left or right of the head (90-degree or -90-degree in figure 413) of plus and minus 618 microseconds." So, add in the reflections you note and 4 microseconds is soon confounded even if it were true.
The other big issue of course is that even if 4 microseconds was vital, the samples on the CD are only at 22 microseconds. 4 microsecond detail doesn't exist. Thererfore the only way you can introduce that level of detail is to synthesise it through guess work.
Yes, you are right, there is no detail in a Red Book CD that occurs any faster than ~22.68uS, though you do need some post-processing of the digital bitstream in order to achieve the desired result.
In the Naim DAC / NDS / NDX / ND5 XS / SuperUniti / DAC-V1, this is takes place at 705.6 kHz (for CD-based material @ 44.1kHz at 16x oversampling), or every ~1.42 uS, using a combination of a floating-point DSP and a Burr-Brown DAC IC.
Intermediate editing of DSD masters (as 32-bit / 352.8kHz DxD) in a PCM-based workstation (such as Pyramix) occurs at half that speed, or every ~2.83 uS, without even taking into consideration the output stage of the DAC used to monitor the process.
The Pacific Microsonics PMDx00 digital filters used in the Naim CD555 / CDS3 / CDX2 / CD5 XS / CD5x (PMD200) and CDS2 / CDX (PMD100, some CDXs with PMD200) also generate output samples to feed through the Burr-Brown DAC IC every ~2.83 uS (8x oversampling). The first Naim CD player product with HDCD (CDX CD player) was released in 1998, about sixteen years ago.
Are you beginning to see a trend here?
I think it's safe to say that nearly everyone in the hi-fi industry (including Yamaha, by the way) has come to understand 8x / 16x oversampling as the minimum order-of-magnitude necessary to convert Red Book CD-quality digital audio to an analogue waveform without significant audible artifacts, which, not by chance, happens to generate intermediate samples in time increments less than 4 uS.
Posted on: 21 June 2014 by Foxman50
Originally Posted by analogmusic:
Actually Graeme it's more you don't have the manners to understand that this is a Naim forum
You really are taking full advantage of the tolerance of the host of this forum
Originally Posted by Foxman50:
Simon
Its quite funny really, i can only compare this with my daughter.
she will refuse to try some food because she gets it in her head that she wont like it. No matter how much ill sit there saying just try it you may like it, but if you don't try you wont know. Very frustrating when your just tying to help.
The main difference is she was 8.
Maybe that says it all
Graeme
Would you kindly point out an example.
As far as im aware ive not stated that this unit is better than any Naim product. Im certain of this as ive not compared any. As such im not sure how im doing what you suggest.
in fact i have tried a couple of devices to replace my NDX but have not been happy with the results so am sticking with the NDX at present.
just out of interest would you kindly say why you frequent this thread when clearly it upsets you so much. Im just curious.
Graeme
