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: 03 June 2014 by Solid Air

Maybe a dumb question, so I beg forgiveness in advance . . .

I have a Qute and a NAP100. If I were to fit a new DAC, eg Hugo, where in the set-up would it fit?

Thanks,

Alex

Posted on: 03 June 2014 by Jan-Erik Nordoen

Originally Posted by Hook:

Originally Posted by Jan-Erik Nordoen:

...The analog section is quite simple, apparently. There are some explanations by Rob Watts on the Head Fi Hugo thread. If I find time, I'll locate them, or perhaps Hook has bookmarked them ?

Watts from Post 3293...

Nicely Hookmarked,

Thanks !

Posted on: 03 June 2014 by Jan-Erik Nordoen

Originally Posted by Solid Air:

Maybe a dumb question, so I beg forgiveness in advance . . .

I have a Qute and a NAP100. If I were to fit a new DAC, eg Hugo, where in the set-up would it fit?

Thanks,

Alex

Between the Qute's digital out and the NAP 100's analog input.

But, you would lose remote volume control of the Qute.

Posted on: 03 June 2014 by Aleg

Originally Posted by Jan-Erik Nordoen:

Originally Posted by Solid Air:

Maybe a dumb question, so I beg forgiveness in advance . . .

I have a Qute and a NAP100. If I were to fit a new DAC, eg Hugo, where in the set-up would it fit?

Thanks,

Alex

Between the Qute's digital out and the NAP 100's analog input.

But, you would lose remote volume control of the Qute.

Or in front of Qute analog in.

Posted on: 03 June 2014 by flammenwerfer

Originally Posted by tonym:

Originally Posted by flammenwerfer:

After 14 pages talking about the Hugo's custom dac chip and how it is different from using the usual off the shelf dac packages , our Mr Wahlberg here still thinks that..

The major differentiating factor in SQ of a decently DAC in this day and age is in the analogue section.

In the case of the standard, "off-the-shelf" DAC chips used in the vast majority of DACs that's probably the case.

Well, writing your own DAC firmware on an FPGA is too much focus on frippery.

Everybody knows its the analogue section that matters.

Posted on: 03 June 2014 by Jan-Erik Nordoen

Originally Posted by Aleg:

Originally Posted by Jan-Erik Nordoen:

Originally Posted by Solid Air:

Maybe a dumb question, so I beg forgiveness in advance . . .

I have a Qute and a NAP100. If I were to fit a new DAC, eg Hugo, where in the set-up would it fit?

Thanks,

Alex

Between the Qute's digital out and the NAP 100's analog input.

But, you would lose remote volume control of the Qute.

Or in front of Qute analog in.

But of course (slaps hand to forehead).

All depends on how he wants to use the external DAC.

Posted on: 03 June 2014 by tonym

"Everyone" being?

Posted on: 03 June 2014 by Aleg

Originally Posted by tonym:

"Everyone" being?

Tony

don't respond his monniker "flammenwerfer" (meaning "flame thrower") already indicates he is just trolling. Best to ignore him, he is not bringing anything positive.

Posted on: 03 June 2014 by Jan-Erik Nordoen

Originally Posted by Aleg:

The Hugo seems quite cable agnostic.

Can anyone recommend a good USB to mini-USB cable ?

Jan

Some dealers supply the Hugo with a Vertere d-fi usb-to-micro usb cable.

Thanks Aleg. Any experience of this cable ?

Posted on: 03 June 2014 by Aleg

Originally Posted by Jan-Erik Nordoen:

Originally Posted by Aleg:

The Hugo seems quite cable agnostic.

Can anyone recommend a good USB to mini-USB cable ?

Jan

Some dealers supply the Hugo with a Vertere d-fi usb-to-micro usb cable.

Thanks Aleg. Any experience of this cable ?

Not yet, just got my Hugo in with the Vertere cable, but all is still in the box.

Posted on: 03 June 2014 by Simon-in-Suffolk

Originally Posted by analogmusic:

Hi Simon I might have missed your post

How does your Hugo compare to NDX and also to your NDAC?

which one do you prefer and why?

I rate your opinion quite highly

Thanks

Hi, I use my NDX to feed my Hugo. My view of the Hugo is here

https://forums.naimaudio.com/to...48#36342540955634848

i hope you find it of some interest, and yes I no longer have my NDAC.

Simon

Posted on: 03 June 2014 by Marky Mark

Originally Posted by Jan-Erik Nordoen:

Mark, see section 3 below, 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.

Given a CD has been produced at 44 kHz this means inserting samples not present in the CD. An oversampling technique Naim have used previously.

The timing of the 44,000 samples per second in the CD are correct. They are the baseline - interpolation does not change them. If the CD recording itself has the wrong timing then filters cannot fix that after the fact.

If you think of these baseline 44,000 samples as the metronome, how it would be possible to get estimated samples between these badly wrong in a one second time period using even basic interpolation?

2. RF noise has a major influence in sound quality, and digital DAC's create a lot of noise. Hugo has the most efficient digital filtering of any other production DAC - it filters with a 3 stage filter at 2048 FS. The noise shapers run at 104 MHz, some 20 times faster than all other DAC's (excepting my previous designs). What does this mean? RF noise at 1 MHz is 1000 times lower than all other DAC's, so noise floor modulation effects are dramatically reduced, giving a much smoother and morenatural sound quality.

3. The lack of DAC RF OP noise means that the analogue section can be made radically simpler as the analogue filter requirements are smaller. Now in analogue terms, making it simpler, with everything else being constant, gives more transparency. You really can hear every solder joint, every passive component, and every active stage. Now Hugo has a single active stage - a very high performance op-amp with a discrete op-stage as a hybrid with a single global feedback path. This arrangement means that you have a single active stage, two resistors and two capacitors in the direct signal path - and that is it. Note: there is no headphonedrive. Normal high performance DAC's have 3 op-amp stages, followed by a separate headphone amp. So to conclude - Hugo's analogue path is not a simple couple of op-amps chucked together, it is fundamentally simpler than all other headphone amp solutions.

These last two points discuss the RFI chestnut again. RFI might also be dealt with by separation of digital and analogue stages. If isolated there is no need to filter beforehand. A digital filter might help address a designer's challenges in either isolation or in the analogue section.

Hugo has an active stage. It still operates upon the signal so simplicity is a matter of perception rather than the reality of a passive component. I am not sure how you could hear every passive stage. What you would hear though is the one active stage.

Thanks Jan. Some thoughts above. Will try a Hugo sometime so just more wild theory for now.

Posted on: 03 June 2014 by Marky Mark

Originally Posted by Hook:

Originally Posted by Jan-Erik Nordoen:

...The analog section is quite simple, apparently. There are some explanations by Rob Watts on the Head Fi Hugo thread. If I find time, I'll locate them, or perhaps Hook has bookmarked them ?

Watts from Post 3293...

In a conventional high performance DAC you have two I/V converters, a differential to SE converter, then a headphone OP stage. That means the signal has to pass through 4 active stages, plus a lot of passive components to do the filtering.

With Hugo there is only one active stage - an I/V converter, which just happens to have a high power discrete OP stage. Also, because Hugo does a huge amount of oversampling (2048 times) and filters the noise digitally, and because pulse array DAC also has innately low out of band noise, then the RF filtering can be simple. So passive components in the direct signal path is two caps and two resistors.

So the whole analogue chain direct signal path is only 4 passive components and a single active stage. That's it. And its one reason why Hugo is so transparent....And why there is only one OP feeding 4 connectors.

...but who's counting?

ATB.

Hook

It doesn't matter whether there is one active stage or four. What matters is the cumulative effect of the one or more active stages and (more importantly) whether you like it.

One extremely active stage could equal four not very active stages for example. Once it has one active stage it is no longer passive. All that is left is whether you like the effect created.

Posted on: 03 June 2014 by james n

An extremely active stage. That's a new one. Is there an extremely passive equivalent too ?

Posted on: 03 June 2014 by Marky Mark

No, passive is passive. The impact active stages have varies. If they all had the same effect then all Naim pre-amps would sound the same for starters. Having one is not necessarily 'better' than having more than one as seemed to be the implication.

Posted on: 03 June 2014 by Hook

Originally Posted by Marky Mark:

It wasn't an implication, it was what Watts said. Multiple active stages implies filtering with passive components at each stage. Simple is better -- more transparent -- according to him.

If you disagree, feel free to post your thoughts on the Head Fi thread. There's a good chance Watts will respond.

Hook

Posted on: 03 June 2014 by Marky Mark

You're keeping a healthy distance from it there Hook.

Given active stages all have different effects, it is obvious one is not necessarily better than two.

Posted on: 03 June 2014 by Hook

Originally Posted by Marky Mark:

You're keeping a healthy distance from it there Hook.

Given active stages all have different effects, it is obvious one is not necessarily better than two. Completely obvious.

You are correct. My main reason is that I am not buying one anytime soon.

Am in the middle of a large vinyl reduction project. Going through all 3500+ records, and boxing up all that I am unlikely to play again in the future. Goal is to get to about 2500. It's fun -- am going A-Z, and now up to my Dexter Gordon albums. Have at least a couple of months to go. Until done, my NDS is not getting a lot of play time.

If I had the time, or even if I had a long holiday coming up soon, I'd buy a Hugo for my headphones. Looks like great VFM. But for my main setup, am thinking that the next revision of Chordette or QBD might be even better. And by then who knows, maybe Naim has released something new. Am still very happy with my NDS, and so in no rush at all. But I do find this Chord discussion interesting, both here and over there.

ATB.

Hook

Posted on: 03 June 2014 by cat345

Originally Posted by Hook:

ATB.

Hook

Wonder how it will be called. Huguette?

Posted on: 03 June 2014 by Steve J

Hook,

As wat posted earlier, it is unlikely there will be an upgrade to the Chordette or QBD for at least 12 months as Chord are very busy with the demand of the Hugo which has surprised them somewhat.

Good luck with the vinyl sort out.

Steve

Posted on: 03 June 2014 by james n

Originally Posted by Marky Mark:

I'm not sure why you are that concerned with whether the output stage is passive or active. It's all down to the application and the implementation - given the Hugo seems to be seen as a bit of a game changer, it looks like the designer has made a good choice. If you think not then i'm sure Mr Watts would welcome a peer review of his design by some random chap on the internet

Posted on: 04 June 2014 by Marky Mark

Originally Posted by james n:

Originally Posted by Marky Mark:

It seems you're keeping a safe distance from it too. 'Seems to be seen' and 'looks like.' 'It's all down to the application and the implementation' you advise us sagely. Yet that is what we're discussing I thought?

Why don't you address some of the non sequiturs in the blurb rather than worrrying about peer reviews? For a start, you might share with us all your thoughts on how it gets the timing perfect, given the [presumably] incorrect timing in the 44,000 samples per second found on the CD, thereby completing a full circle to the analogue recording before the CD was cut. If you don't like that one, how about your thoughts on why one active stage must be better than two?

When people get defensive, I sometimes wonder if they may be an owner or a dealer. On the other hand, if you've simply read What Hifi and have become giddy with excitement then all is forgiven.

Posted on: 04 June 2014 by james n

To be honest Mark, i'm interested in the Hugo from an engineering perspective but also rather surprised how easily it's unsurping the Naim offerings. I'm not a dealer and unlikely to be an owner as it doesn't really fit with my system. I'll leave the thread to the owners and prospective owners as i'm just an interested observer

PS - i don't read WHF either.

Posted on: 04 June 2014 by Marky Mark

James, I share the same interest. Believe me, if feeding active speakers it beats a Naim set-up then the whole lot is going. I doubt it will but I don't know that for sure so would like to find out. Whilst I consider whether to demo, I admit I am somewhat jaundiced by the latest and greatest from the industry so try to sniff out any possible BS in the blurb before expending any energy on the matter.

The form factor of the Hugo is what posters like Graeme and myself have been pushing for. I for one would be quite happy if my hi-fi was heard but not seen. I hope it delivers on the hype and if it does I wish Chord every success with it. It will be a real game changer.

Posted on: 04 June 2014 by james n

I'll be interested to read your findings when you try one Mark.

James