Thoughts on a bunch of DACs (and why delta-sigma kinda sucks, just to get you to think about stuff)
Jun 11, 2015 at 3:20 PM Post #5,776 of 6,500
Why do I feel like I have been reading alot of schiit flying around in last few pages?
lol
:wink:
Like watchn a multiple tennis tennis match, i feel like I took in too much.
:)
So far this is the last quote I enjoyed most:

The issue with sigma delta dacs is that they take 16bit/24bit input and converts them to Bitstream data @ 5bits(5bits for sabre/hugo/dave or less bits for other designs) 2.8MHz(for Ess Sabre)/104MHz(Dave). From what I understand this conversion process is quite destructive(time domain or samples wise) and is a lossy/decimation process. Also there's alot of complex feedback algorithm at work here(in the case of hyperstream), these feedback systems/noiseshaper algorithms are not fully understood by the dac designers(check out video of rob watts explaining noise shaping simulation below, perplexing even at his level). So much "black arts" involved in designing sigma delta dacs when a pragmatic dac designer can just stick to high precision R2R to get really good signals out of the decoder and design whatever filters codes/analog stage necessary to get good sound. The amount money spent on "DSP cores/FPGAs" noise shaping system is getting more expensive than just getting a highly precision R2R chip, not to mention with all these high Mhz cores, they might leak higher emi/rfi(electrical noise) into the surrounding audio components and require more filtering/pcb noise mangement/power conditioning and etc etc(increased cost/design time).

Rant: effing money grubbing texas instruments killing off the pre Burr-Brown true R2R chips.

Esstech patent(relates to Sabre Hyperstream modulator)
http://www.google.com/patents/US8350734
 








 


Edit:
should have done a few takes,
so he could smooth out what was trying to be said..
:)
 
Jun 11, 2015 at 3:23 PM Post #5,777 of 6,500
  I never said its drawback,what you mean R2R is like ramp,tell me more about it ,thats interesting

Sorry for miscommunion, I speaking Slovenly,  (English as sex and language.)  R2R is like ramp, see diagram:
 

 
No strares steps here, is steep ramp parts we watch (see tape, angle).  This is missing many small "steppings tones" t,hat are challenged listener.  Overly smooth sound, like airbursh celebritory on mangazine.  
 
For contrasting, see record, so many groovings, every frequentcy is reprersent, this is true aurdinophile and sterps are reason why!
 
Jun 11, 2015 at 3:38 PM Post #5,778 of 6,500
I have been purchasing and researching dacs for a long time and the very first time I have ever heard something about "taps" is recently when reading the Chord website and now for the second time in the Chord video above.  What am I missing here?  WTH is a tap?
 
Jun 11, 2015 at 3:38 PM Post #5,779 of 6,500
Wow, calling people's products garbage and saying with all due respect don't work. You essentially said his opinions are garbage and his explanations are nothing but spin. Pretty low-blow there. For the record my D-S DAC sounds quite good, but I'm sure I don't have good hearing and I just can't tell that it is crap.


+1
I wish ppl would stop throwing those flat "DS is crap" statements. It's just useless lalala, IMHO.

Also hope that our KeithEmo expert here would write a bit more concise .. well informed and well though msges but just too long!
 
Jun 11, 2015 at 3:44 PM Post #5,780 of 6,500
 
Wow, calling people's products garbage and saying with all due respect don't work. You essentially said his opinions are garbage and his explanations are nothing but spin. Pretty low-blow there. For the record my D-S DAC sounds quite good, but I'm sure I don't have good hearing and I just can't tell that it is crap.


If you notice, I'm only singling out the DACs and I didn't say anything about his opinion.  Anyone can feel free to disagree with me but, as and Engineer I can tell you that DS technology is inferior and I stand by that.  Any amount of supporting circuitry to a DS chip is merely a palliative measure.  The scheme if fundamentally flawed and innacurate.  Like I said, there's a reason companies like MSB and Schiit are using R2R.  BTW, I challenge you to A/B your DAC to a good R2R solution.
 
Jun 11, 2015 at 4:55 PM Post #5,781 of 6,500
 
If you notice, I'm only singling out the DACs and I didn't say anything about his opinion.  Anyone can feel free to disagree with me but, as and Engineer I can tell you that DS technology is inferior and I stand by that.  Any amount of supporting circuitry to a DS chip is merely a palliative measure.  The scheme if fundamentally flawed and innacurate.  Like I said, there's a reason companies like MSB and Schiit are using R2R.  BTW, I challenge you to A/B your DAC to a good R2R solution.


I have said before that I do not doubt that it is possible that a R2R can sound better than a D-S DAC design; I would be a fool to ignore all of the input from extremely experienced people. What I do take exception to is the blanket kind of D-S DACs are fundamentally flawed and will sound worse. You are an engineer, I certainly respect that accomplishment, but that in itself does not guarantee you will be completely correct all of the time. I have heard from other engineers who feel that a well done D-S DAC can sound quite good actually. I know my DAC sounds quite good.
 
I am also interested to know if you have yourself been the subject in a well done blind listening test and you are able over multiple valid trials to always pick out an R2R design over a D-S, or that you in such a test you always preferred an R2R sound signature. I think at the heart of this electronic pissing match is that there can be a difference between measurement and audibility. So would you say that any R2R DAC will sound better than any D-S DAC? If so, that is fine, but the only measurement that matters is the human brain so blind listening tests are of more importance in my view than pure theory.
 
Again for the record, I myself am likely to purchase an R2R DAC in the very near future and I have no reason to doubt that a well done R2R can be a better sounding DAC. I do feel that despite the fervor and pedigree of those who strongly favour R2R over the D-S, that in and of itself does not mean that all D-S implementations are going to sound the same, nor does that preclude that many people might actually prefer a D-S signature.  
 
Jun 11, 2015 at 5:10 PM Post #5,782 of 6,500
IMO all you have to do is hear the Yggdrasil and you will understand the praise for it. There are a lot of people arguing that it could not sound superior who haven't even heard it. I wish was in Ottawa for the meet and comparison, because I heard clear, distinct differences myself. This to me is fairly clear cut in some respects. I haven't compared it with more expensive DACs myself, but I personally agree with what Purrin has written in his rankings. I look forward to your results, I think it's clearly audible.
 
Jun 11, 2015 at 5:13 PM Post #5,783 of 6,500
 ...as and Engineer I can tell you that DS technology is inferior and I stand by that

what sort of Engineer?
 
I r one too - and have used many types of ADC, DAC written DSP code designing, developing electronics for Scientific and Industrial instrumentation and motion control products for a few decades as well as following audio tech too over that time
 
Delta Sigma is a fine technology, has advantages and weaknesses, has had a mixed history in audio with single bit "DSD" being pushed out to consumers when there were unappreciated flaws - Vanderkooy and Lipshcitz are on target with criticism of single bit DS
 
but they are fine with multibit: http://sjeng.org/ftp/SACD.pdf
 
 
in fact you could step back to the studio and ask what ADC technology is being used - I'm fairly certain it is overwhelmingly DS ADC today
 
looks like some have gone there already in this thread: http://www.head-fi.org/newsearch/?search=ADC&resultSortingPreference=recency&byuser=&output=posts&sdate=0&newer=1&type=all&containingthread%5B0%5D=693798&advanced=1 a few of the posts go on about studio ADC tech 
 
Jun 11, 2015 at 5:58 PM Post #5,784 of 6,500
 
Keith:
 
With all due respect, let's face it.  DS sucks.  It's a cheap-***, flawed, no-brainer solution.  Don't get me wrong, I love Emo.  In fact I'm running an Emo spinner (ERC-3) and amp (XPA-200).  But, tell your boys at Emo (for their own sake) to thow those POS XDA-2 and DC-1 DACs in the garbage, go back to the drawing board, and create a real DAC with a multi-bit chip in it.  There's a reason why companies like Schiit and MSB are using R2R with custom filters and SHARC DSPs.  Hell even Behringer is using a SHARC in it's ~$300 DEQ2496.  Peace out.

 
I'm curious - do you actually have anything factual against Delta-Sigma DACs - other than that they don't cost enough and they're too easy to use?
(Or do you consider "It just sucks" to be a technical justification...?)
 
The simple reality is that Delta-Sigma DACs do happen to currently offer the best "bang for the buck"... which is probably why most DACs sold these days use them (including all of Schiit Audio's other models). And I can assure you that, if Emotiva ever decides to come out with a $2000+ DAC, we will consider all of the available technology and use whichever one allows us to deliver the best performance and sound quality while staying within the available budget.
 
However, excluding marketing rhetoric and "intuitive assumptions", I'm still curious to hear precisely what you believe R2R DACs ACTUALLY DO BETTER than Delta-Sigma DACs - specifically in the context of digital audio. (Since it is much cheaper to design and build a Delta-Sigma DAC than an R2R DAC, I would reasonably expect there to be plenty of poor quality low cost Delta-Sigma DACs available, and very few low cost R2R DACs - whether good or bad. However, that doesn't in any way suggest which technology is better at a given price point where both exist, it merely suggests that you can't practically design and sell a low cost R2R DAC.)
 
Incidentally - if you check the manual - you will see that the DEQ2496 uses AKM Delta-Sigma DACs for its D/A conversion. (I didn't see the Sharc processors mentioned by name, but the DEQ2496 inludes both "two high quality DSP processors", and quite possibly a separate CPU for the front panel and display, so it may be using Sharc processors for one or both of those.)
   
MSB makes what look to be some very nice DACs (I've never heard one). At a starting price over $6k (for the "basic" model), I think it's fair to consider them "cost no object". Stereophile did a review on one of their lower models, with measurements, and it seemed to spec out quite well (although I didn't see any measurements that were clearly superior to those I would expect from a high-end Delta-Sigma DAC.) So, back to the topic of the discussion, I'm still waiting to hear what's better about their DAC, along with some reasonable indication that the difference is BECAUSE it's not Delta-Sigma.      
 
http://www.stereophile.com/content/msb-technology-analog-dac-da-converter-and-analog-power-base-power-supply

 
 

 
Jun 11, 2015 at 6:20 PM Post #5,785 of 6,500
 
I have said before that I do not doubt that it is possible that a R2R can sound better than a D-S DAC design; I would be a fool to ignore all of the input from extremely experienced people. What I do take exception to is the blanket kind of D-S DACs are fundamentally flawed and will sound worse. You are an engineer, I certainly respect that accomplishment, but that in itself does not guarantee you will be completely correct all of the time. I have heard from other engineers who feel that a well done D-S DAC can sound quite good actually. I know my DAC sounds quite good.
 
I am also interested to know if you have yourself been the subject in a well done blind listening test and you are able over multiple valid trials to always pick out an R2R design over a D-S, or that you in such a test you always preferred an R2R sound signature. I think at the heart of this electronic pissing match is that there can be a difference between measurement and audibility. So would you say that any R2R DAC will sound better than any D-S DAC? If so, that is fine, but the only measurement that matters is the human brain so blind listening tests are of more importance in my view than pure theory.
 
Again for the record, I myself am likely to purchase an R2R DAC in the very near future and I have no reason to doubt that a well done R2R can be a better sounding DAC. I do feel that despite the fervor and pedigree of those who strongly favour R2R over the D-S, that in and of itself does not mean that all D-S implementations are going to sound the same, nor does that preclude that many people might actually prefer a D-S signature.  

I don't disagree with you that DS can sound very good and I in fact own a few DS DACs myself.  I just argue that R2R has the potential to sound even better due to the fact that it is a superior D to A technique which is something I believe that manufacturers such as Schiit and MSB have acknowledged and chose to go that route even though it is a more difficult and expensive one.  I wish more manufacturers would consider alternate approaches instead of sticking with the easiest/cheapest approach.  It would be foolish to say that every R2R DAC sounds better than any DS DAC because, as you know, there are other factors involved like the analog output stage, power supply, etc.  And you're right, some people may prefer the DS signature which they are entitled to prefer.  Personally, for the best sound, I choose to go with the superior R2R approach.  And certainly different DS implementations can sound different and the same applies equally to R2R.  The good thing about DS is that it's inexpensive to design/manufacture which is a pro.  In certain cases, DS is the best way to go.  In fact for mobile use, I quite like my minuscule Audioquest Dragonfly.  Does it sound as good as my GDA-600 no?  But, my GDA-600 isn't very portable and probably cost a lot more back in the day.  Also, if I loose/break my Dragonfly I'm not likely to shed any tears either.  And you're right, I'm human too which means I do make mistakes from time to time i.e. I'm not always right.  However, for companies like Emotiva trying to sell high end DACs, I suggest they consider a different approaches other than DS for their own good and not try to make poor excuses as to why they should not do so.
 
Jun 11, 2015 at 6:28 PM Post #5,788 of 6,500
  what sort of Engineer?
 
I r one too - and have used many types of ADC, DAC written DSP code designing, developing electronics for Scientific and Industrial instrumentation and motion control products for a few decades as well as following audio tech too over that time
 
Delta Sigma is a fine technology, has advantages and weaknesses, has had a mixed history in audio with single bit "DSD" being pushed out to consumers when there were unappreciated flaws - Vanderkooy and Lipshcitz are on target with criticism of single bit DS
 
but they are fine with multibit: http://sjeng.org/ftp/SACD.pdf
 
 
in fact you could step back to the studio and ask what ADC technology is being used - I'm fairly certain it is overwhelmingly DS ADC today
 
looks like some have gone there already in this thread: http://www.head-fi.org/newsearch/?search=ADC&resultSortingPreference=recency&byuser=&output=posts&sdate=0&newer=1&type=all&containingthread%5B0%5D=693798&advanced=1 a few of the posts go on about studio ADC tech 

FWIW (which may be not much), I'm an Electrical/Electronics Engineer.  At least that's what it says on my diploma.  Obviously, different D to A techniques are going to have different pro/cons.  I totally agree.   I'm just sick of manufacturers taking the cheap/easy route and I praise Schiit for taking the time/effort to try something different like they did with the Yggy.  I wish more companies would do that.  DS has it's place for sure, I just don't think it's with high end audio DACs.  Yes, I am aware that ADC is overwhelmingly DS today but that doesn't necessarily make it the best and in fact, I'm pretty sure it's not.
 
Jun 11, 2015 at 7:19 PM Post #5,789 of 6,500
For what it's worth, there are quite a few very positive comments on the Emotiva Stealth DC-1 in this thread. This includes positive comments/recommendations from a number of people who have had extensive experience with quality R2R DACs (Purrin*, Gunner, and myself, just to name three off the top of my head). It's an extremely solid AD1955 implementation, and its features - a balanced DAC that's competitive with the Gungnir, preamp functionality, a headphone amp, remote capability, small form factor, lots of inputs/outputs  - make it a tremendous value. It's definitely not crap. There are tons of D-S DACs that are well worth owning, especially at entry/intermediate-level price points.
 
The intentionally inflammatory title of this thread is to a large extent propaedeutic hyperbole. And I think that the last thing that this hobby needs is every manufacturer jumping on the R2R train just because Schiit has taken a novel approach with the Yggy. Look at the proliferation of cheap, awful Sabre DACs on the market and imagine that repeated all over again but with a different technology. 
 
*Relayed other positive impressions, but didn't audition himself. Just a note so that I'm not putting words into his mouth.
 
Jun 11, 2015 at 7:20 PM Post #5,790 of 6,500
 
What the fellow from Sabre was referring to was that, because of the way the process works, you sometimes end up with a noise floor that varies depending on the content of the signal you're converting (the noise floor is modulated by the content). Since most people agree that a smooth consistent noise floor is in general less annoying than one that is correlated with the signal in some way, this is something worth avoiding (by careful attention to the details of how that mathematical trick is actually accomplished). We can leave the question of whether you can hear the difference between a smooth noise floor and a bad one, and whether different types of noise modulation sound audibly different - when the noise floor in question is better than -120 dB down - for another discussion. (This is only relevant and meaningful if you actually DO notice that the noise between low level passages really is audible - and sounds audibly different between different DAcs.)
 
 

 
The existence of this very thread is down to the difference in sound between D-S DACs and multibit ones - if the audible difference isn't in the shifting noise 'floor' (not necessarily perceivable as noise, but perceivable nevertheless) then what is it?
 
There also seems to be an assumption in your quoting of this '-120dB' figure that you know the relevant bandwidth of the noise. Do you?
 
Incidentally I see in a later post Keith you're claiming that D-S DACs do offer the best bang for the buck. I'm currently designing with the TDA1387 so I guess you were implicitly limiting yourself to current production DAC chips as nothing in the D-S world comes anywhere close to the bang of this chip for anywhere near its cost ($0.08, secondary market). Unless you know better?
 

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