Watts Up...?

Not initially - it will be mic or line level only.
 
But I think it would offer some benefits to do RIAA in the digital domain, so that the analogue is simpler, but that project won't happen until Davina is complete, and no other pressures on my time!
 
Rob

Thank you.
 
https://fr.wikipedia.org/wiki/%C3%89galisation_RIAA
 
I will wait patiently
 

searchofsub said:

Yep, Robs recommendation was the main reason why I purchased my Nighthawks and currently have it paired with Mojo.

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Laughed way too much over reading this, but I had to demo the nighthawks after Robs recommendation myself. Quite liked the Mojo and Nighthawks togheter. Sat in the store two hours straight, lost in time and space listening to my favourite songs.

Rob,

I have a question for you; academic and a touch practical, for an opinion. It is related to my own work.

Using Mojo has allowed for dramatic increase of data. The Mojo "improves" for many months of continual use as the brain adjusts to interpreting and processing signals. This is true for other applications.

In ice hockey, professionals newly promoted find the ice "moves too quickly" and in a few weeks, commonly and enthusiastically report "The ice slowed down" as they learned to adjust to implementing detailed changes in less time.

In training lie detection, one moves from "statement" (written) analysis to, after many months, "discourse" (verbal) analysis. This often takes years to go from "dulled listening" to trained listening. Those early in training (under 12 months) will find that gaps in training will cause them to revert back to dulled inattentive general listening at pre training levels. (Those w years experience report 'no reversion').

For the first time in months, I am without Mojo.

First, I attempted to listen to a song I was long familiar with using Mojo. It was empty, hollow and immediately evident at lesser quality. I could not discern certain instruments I expected with just listening. I had to replay and concentrate to hear the instrument but even with it acknowledged it did not have depth or that "magic."

Next, I tried a portable DAC that gave only little improvement.

Lastly, I abandoned listening via headphones altogether, preferring to wait for Mojo's return.

Can you address the brain's response to the sudden decrease in data after prolonged exposure?

As you can see, I'm curious as to several points though given your profession, I'm not sure you've had the misfortune of being without a quality DAC for too long!

I would appreciate your thoughts. I have found the topic of increased data and the brain to be fascinating to read and I recognize that with Chord DACS the data increase is not the sole attribute of enjoyment but it does appear to set DAVE, Mojo and Hugo apart.

If others have experienced 'DAC Withdrawal" I am interested in learning what it was like for you including how much time acclimating to DAC and how much time in withdrawal. 'What was it like?' and 'did you eventually go back to enjoying music, though less data?' and so on.



Thank you for an interesting thread here. Your generosity of sharing knowledge is something many here are thankful for.

I have been an audio enthusiast for about 40 years now, building gear as a teenager.
 
But the issue of brain burn in, or breaking in, is actually comparatively new phenomena to me; I first experienced it with Hugo - it will be 3 years ago in October. One is used to equipment breaking in, but the idea that the brain will learn strategies to cope with poor sound quality is for me a relatively recent idea. Firstly we need to be clear - nobody understands how the brain does the processing it does to separate sounds out into discrete entities and create placement data too. Quite a lot is understood into which cues are used by the ear to create placement data, but not how it is processed by the brain. Indeed, I don't even think that the question of how the brain separates sounds out has actually been asked - unlike visual processing, where we can get computers to recognise shapes and perceive them as separate entities.
 
So since so little is understood about these processes, science can't give you an answer - we can only go on our own personal experiences.
 
My experience, for what that is worth, is that brain break in is very real, and is a problem related to timing. Specifically, a DAC has to re-create a continuous waveform from time sampled and quantised data. Now sampled data is not something evolution has equipped us to deal with, as its something that only has been around (in evolutionary terms) very recently. Now the ear/brain is used to dealing with harmonic distortion and with noise; and as a child your brain has developed (or you are innately built with) skills to deal with distortion as you own ears are significantly non-linear. But it has no capability to deal with timing errors from sampled data as this is a new problem. DAC's themselves do not re-create timing perfectly - and theory is clear, we need infinitely capable reconstruction filters to perfectly reconstruct the timing of transients at the point the ADC sampled the continuous analogue signal.
 
Now I was well aware of the importance of timing errors, with the initial creation of WTA filters in 1999. But I had underestimated how sensitive the brain is to extremely small timing errors; I took the line that so long as it was accurate to a uS or so, that was good enough. But with Hugo, things sounded very much better, and in ways I had not seen before - notably being able to perceive the starting and stopping of notes, and variations in timbre. Both these things are upset by timing errors. Also, I had this brain break-in observation - I kept on getting the impression that Hugo was sounding better and better - but a new Hugo sounded the same as my old unit - so it was not the hardware that was changing.
 
At the time I did not know what I had done with the design to give this performance, although I had an idea. With the Dave project I found it was down to timing accuracy and that designers need to think in terms of nS and not uS for timing accuracy. For some reason, extremely small timing errors are very significant - any inaccuracy in the timing of transients has consequences for the brains ability to create the illusion of separate sounds.
 
But the consequences of small timing errors has an enormous musical impact - having the brain to work harder to understand what is going on means that you simply can't enjoy the music. But the brain develops coping strategies to try to overcome the timing problem; and these coping strategies need to be un-learnt, hence brain break-in. That's my thinking anyway, but I stress this is only an hypothesis.
 
But once you appreciate digital audio that has timing errors reduced, then I agree with you - there is no going back, and ordinary digital sounds quite awful.
 
Rob

Above @Rob Watts post raised me a question:
 
I am aware now that for non-galvanically insolated DACs (as Mojo), optical/toslink connection is prefered, due to its inmunity to ground loops and RF interference. Correct me if I am wrong, but my understanding is also that USB connection on non-galvanically insolated DACs is slightly more detailed than by Optical/Toslink.
 
My question is: strictly in terms of timing (the topic discussed above by Rob), does USB or Toslink has a preference here? To rephrase: Does Toslink has more accurate timing than USB (or the opposite?) Or timing is indenpendent of the connection used?
 
Thanks,
-Mark.

mark ux said:

  Above @Rob Watts post raised me a question:
 
I am aware now that for non-galvanically insolated DACs (as Mojo), optical/toslink connection is prefered, due to its inmunity to ground loops and RF interference. Correct me if I am wrong, but my understanding is also that USB connection on non-galvanically insolated DACs is slightly more detailed than by Optical/Toslink.
 
My question is: strictly in terms of timing (the topic discussed above by Rob), does USB or Toslink has a preference here? To rephrase: Does Toslink has more accurate timing than USB (or the opposite?) Or timing is indenpendent of the connection used?
 
Thanks,
-Mark.

Click to expand...

 
Actually this is two different timing issues - and in the case of optical and coax everything is re-timed via the DPLL, so the local low jitter clock takes over. Any jitter on the inputs is eliminated completely, so this is not a concern.
 
The timing I am talking about is the reconstruction of transients. You can see this by imagining a transient in an ADC. It is -1v at the sample point, and +0.5v at the next sample point. It crosses through zero at say 15,679 nS after the first sample point. Now assuming the signal in the ADC is perfectly bandwidth limited, then a infinite tap length sinc function filter will exactly reproduce it crossing through zero at +15,679 nS. But with a conventional DAC it will not cross through at +15,679 nS - but could vary by many thousands of nS - and this variation or inaccuracy is highly audible, with very important musicality consequences. It is this timing error within interpolation filters (the filter that takes it from 44.1k up to 705.6k and eventually to 104 MHz within my DAC's) that I am talking about.
 
Rob

Are we just awash in noise floor modulation? And is there any hope of turning back the tide?
 
I came to these sad questions yesterday. My local dealer got the new Peachtree Nova 150 in and it sounded "great" with his Wilson speakers. It's a product using Sabre DAC ESS9018, B&O IcePower class D amplification (which is now pretty load invariant). It obviously has a low noise floor, lots of details, loads of dynamics. Transient timing issues aside, most people would enjoy the sound and particularly for US$1600, especially since most people have not heard Chord DACs.
 
And then I cued up Hamilton the musical and the track It's Quiet Uptown. I said to myself, that's the most exciting I've ever heard this track to sound. Except it's supposed to be a somber, mournful piece of music that is supposed to be smooth sounding. I suspect the noise floor modulation from the Class D amplifier and the Sabre DAC made the sound so bright/grainy/harsh that it made a very smooth sounding piece of music inappropriately exciting. And had I just been listening to the piece in the background, not knowing the context, I would have said the song and the stereo system sounded great.
 
My dealer has told me that a decent proportion of his customers had trouble hearing the advantage of Chord DACs. In fact, one customer took home the Hugo TT and another high-end Sabre DAC home and said for some music, he prefers Hugo TT and others the Sabre DAC. Fortunately, the customer chose Hugo TT because he said he can crank up Hugo TT all he wanted but with Sabre DACs, once the digital volume is too loud, the customer found the sound harsh.
 
The experience made me realize, we are surrounded by noise floor modulation. In our everyday phone conversations, sound is processed through ADCs and DACs which generate noise floor modulation. Most of our music playback at restaurants, coffee shops, at work comes from DAC chips which has noise floor modulations. The drive to energy efficiency and manufacturer cost savings means more and more speakers are powered by class D amplifiers so even more noise floor modulation. Even most concerts are amplified and who knows whether some of them use ADC/DAC chips or class D amplifiers...
 
I remember supposedly some study showing that some younger people prefer 192kbps mp3's over the original lossless files because that's the file format they were used to hearing from iTunes. I am now wondering if people over time would simply learn to like noise floor modulation better, even possibly over original live instrumental or vocal sounds.
 
In the old days of many stereo shops, perhaps there is a way to reverse the trend because if enough audio dealers are committed to showing their customers the way forward by demoing equipments with and without noise floor modulation, maybe we can at least reverse this trend with audiophiles. But as demoing becomes harder and harder, most people are just reading the chorus of internet users raving about gears that they own. If hearing noise floor modulation becomes more and more of the norm, even in audiophile circles, maybe there is no turning back.

Are Class D amps really prone to high noise floor modulation – compared to conventional amps?

jazz said:

  Are Class D amps really prone to high noise floor modulation – compared to conventional amps?

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Absolutely - particularly the ones without any global feedback.

 
My biggest worry with switching amplifiers is the timing of transients issue. The more I work on timing issues, the more I find that the tiniest timing error will have substantial SQ implications. Class D creates subjectively very large timing of transients problems, due to switching activity.
 
Rob

the impact of hugo and mojo , I no longer enjoy music in restaurants and public places. the sound is too harsh , the vocals don't seem to have kind of throw and focus in restaurants .

rob watts said:

 

jazz said:

  Are Class D amps really prone to high noise floor modulation – compared to conventional amps?

Click to expand...

Absolutely - particularly the ones without any global feedback.

 
My biggest worry with switching amplifiers is the timing of transients issue. The more I work on timing issues, the more I find that the tiniest timing error will have substantial SQ implications. Class D creates subjectively very large timing of transients problems, due to switching activity.
 
Rob

Click to expand...

 
 
That might partly explain why Sony's ZX1 sounds so horrendously artificial and contrived, to my ears.

So now that we're ruined for all other forms of digital to analog conversions, what's the answer for multi-channel reproduction in one's living room or theatre?
 
Rob, I wish I understood even 20% of what you're talking about, but I love the one product of your design (Mojo) that I'm able to afford and can't wait to hear the resulting recordings from your Davina project/product. I only hope it will be accepted and used by the recording community at large. Your work on improving digital recording and reproduction is one that I highly appreciate and it's obvious from other Chord product threads, many others do as well. Sending good juju to you for a long and healthy life making all of ours sound better.

lamosca said:

 
 what's the answer for multi-channel reproduction in one's living room or theatre?

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Perhaps buy 3 Mojos, and then...
 
www.head-fi.org/t/766517/chord-electronics-dave/1320#post_12248852

mython said:

   
 
Perhaps buy 3 Mojos, and then...
 
www.head-fi.org/t/766517/chord-electronics-dave/1320#post_12248852

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How does that get you three separate two-channel signals to feed into the Mojos though (for 5.1 surround)?