Author Topic: DDDAC 1794-NOS 24-192  (Read 174863 times)

Offline kajak12

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Re: DDDAC 1794-NOS 24-192
« Reply #40 on: November 22, 2012, 11:40:52 PM »
http://www.dddac.com/dddac1794_test_specs.html

did anybody see at all results like this within a DAC whatsoever ?
One day tuyen will bring his dac over it would be interesting if its got potential i might buy one to play with
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline zenelectro

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Re: DDDAC 1794-NOS 24-192
« Reply #41 on: November 23, 2012, 02:00:09 AM »
Naaaa, think the transformers will beat any cap in that position!
V
Hmmm maybe i should sell my duelunds and get transformers for the kdac????

Unfortunately wont work very well.
OP transformer needs to be driven from very low impedance to sound best.

For high impedance drive (like KD) the only option is a high impedance transformer
which generally aren't as good as low impedance type.

There are exceptions such as a high impedance stepdown, but then you will need
more OP level from KD.

Oh BTW, you will still need a coupling cap to take DC off transformer primary.

No free lunch.


Z





 

Offline ozmillsy

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Re: DDDAC 1794-NOS 24-192
« Reply #42 on: November 23, 2012, 08:25:02 AM »
Well the issue here, is that from my reading,  balanced designs inherently reduce even order distortions.

Odd order distortions (the nasties) are still there.

Some suggest that the removal of even order distortions results in clinical sound that is artificial .

I'd like to know more about this topic, because I admit that it's an area that I don't understand well.

It's certainly peaked my interest.    A few years ago Lampizator added a tube output stage to a dual mono pcm1794 based cd player, and was in raptures about his result.  Kajak, I think that is something that needs to be attempted.   
It's all about the music,, not the equipment.

tuyen

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Re: DDDAC 1794-NOS 24-192
« Reply #43 on: November 23, 2012, 09:19:22 AM »
mmmmhhhhhh, wonderful, finally Doede has visualised the first test results... if you are interested you might have a look here:

http://www.dddac.com/dddac1794_test_specs.html

did anybody see at all results like this within a DAC whatsoever ?

well, to be able to "listen" to this, one might be able to transport these square through one's amplification chain without alteration, and then it's only a question of your speakers (and room)...

happy reading !

Hi Reinhard

I did notice that yesterday and it was refreshing to see the results.

Spoke to Doede who says the ps kits will be ready by end of year which I'm a bit excited about. Can stop the lab ps I am using to power the main board. I am also currently using the USB cable power for the 5v. The ps kit should help with that too.

Are you still on the single dac board?  I am thinking of going another 3 boards when I order the ps, if funds permit.

In terms of SQ, so far so good.  Working great connected to my valve preamp.

Have tried a few high res recordings from ACT label.  Has the extra level of fidelity that is great to experience.

Are you guys ready for the Japanese session?  Is Jean and Stefano joining you?
« Last Edit: November 23, 2012, 09:46:47 AM by tuyen »

Offline rhlauranna

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Re: DDDAC 1794-NOS 24-192
« Reply #44 on: November 23, 2012, 10:15:21 AM »
Hi Tuyen,

well, "the results" were so listenable from the first second on, reaching magic on my "radio"...

to answer your questions:

although it is still a fortnight to go we will have this weekend some sort of a final check... with Doede...

he will bring his own DAC with the Sowters with him and this will stay till the Japanese session is over... Doede just told me that after his burning in the sound still has become better (as was with my single deck for some 200 hours, a fact which I wouldn't have believed if somebody would have told me so before...)

in the meantime he has finished more decks for me, nr two, three and four, and they will be implemented on coming sunday... so they will get burnt in just in time...

regarding your question with Win 7 and 8, meanwhile I have jumped to a totally new machine and windows 8, so everything seems to get adjusted to that level that is possible at the moment...

and yes, of course, Jean and Stefano will join us, and André Klein from France with his WE15E and so on...will be with us as well, the whole thing has become some sort of brain trust like building and experimenting on a space shuttle... it seems that there is no longer one single person able to do "everything" "just exactly perfect" alone within such a dimension (and I have to admit I like it), and the gains in sound quality are still simply breathtakingly awesome... (a quality level of which even we couldn't have been dreaming of some two or three years ago)

furthermore we will have in addition for the first time as our guest Mr. Thomas Schick from Berlin, the well known tonearm constructer and recording expert, if you are interested, feel free to go here:

http://www.thomas-schick.com/

yes, this is really a very interesting and exciting fortnight to come...

« Last Edit: November 23, 2012, 10:51:22 AM by rhlauranna »

tuyen

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Re: DDDAC 1794-NOS 24-192
« Reply #45 on: November 23, 2012, 05:13:01 PM »
Awesome Reinhard. Please keep us in the loop if possible!

I'm guessing most of them are currently attending the annual European Triode Festival in Berlin, at the moment. That would be lots of fun too..

Oh, please tell Mr Schick that I am still waiting for my tonearm!!$#@

Offline rhlauranna

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Re: DDDAC 1794-NOS 24-192
« Reply #46 on: November 24, 2012, 05:01:38 AM »
my, oh my, oh my...

so for all, who might be interested in "perfect" bass, have a look here, how it should be generated before being amplified:

http://www.dddac.com/dddac1794_test_specs.html

and please go here to the 20 Hz picture... this is simply spectacular and that's what it is all about, if you don't have this in the origin you will never ever get a bass amplified in reproduction that sounds really "natural"...

you should hear this... I am rather convinced that it doesn't get any better than this...

yes, and here tested in another surrounding and in direct comparison with other (commercial) DACs...

http://www.dddac.com/dddac1794_sound2.html

have fun...
« Last Edit: November 24, 2012, 08:45:40 AM by rhlauranna »

Offline zenelectro

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Re: DDDAC 1794-NOS 24-192
« Reply #47 on: November 24, 2012, 12:15:12 PM »
my, oh my, oh my...

so for all, who might be interested in "perfect" bass, have a look here, how it should be generated before being amplified:

http://www.dddac.com/dddac1794_test_specs.html

and please go here to the 20 Hz picture... this is simply spectacular and that's what it is all about, if you don't have this in the origin you will never ever get a bass amplified in reproduction that sounds really "natural"...

you should hear this... I am rather convinced that it doesn't get any better than this...

yes, and here tested in another surrounding and in direct comparison with other (commercial) DACs...

http://www.dddac.com/dddac1794_sound2.html

have fun...


I very much like zero oversampling 1794 - and this implementation looks pretty good, but the measurements are a joke.

*any* DAC will do these measurements at 20Hz If they don't, the DAC is broken.

This is purely what you would expect from a zero oversampling 24 bit / 192k DAC. End of story.

There are some things they can do - such as perfect square waves.
There are some things they will fail, such as 2 tone IMD 18kHz / 19kHz. It will be obliterated with imaging artifacts.
As they say - zero oversampling is what it is.

What you really want to see - is out of band noise > 20KHz.
Since it is a zero oversampling DAC and we want to run minimal analog (hopefully no) filtering, the out of
band noise is very important.

This is where delta sigma (aka PCM1794 / ESS Sabre etc) DAC's have dirty secret.

Unfortunately these FFT plots that have virtually zero resolution to start with to try and characterize the performance of a
super high performance DAC such as 1794.

See below for an FFT plot of 1794 with resistive OP I-V. The scale goes down to -150dB.
As you can see, it works very well and the DAC stays linear.

As stated I think wideband (100kHz) plots with good resolution might be more meaningful.


cheers

Z
« Last Edit: November 24, 2012, 12:21:49 PM by zenelectro »

Offline omodo

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Re: DDDAC 1794-NOS 24-192
« Reply #48 on: November 24, 2012, 01:48:39 PM »
Quote from: tuyen link=topic=842.msg12339#msg12339 date=
Oh, please tell Mr Schick that I am still waiting for my tonearm!!$#@

Me too.. 15+ months and counting :-X

Offline vitavoxdude

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Re: DDDAC 1794-NOS 24-192
« Reply #49 on: November 24, 2012, 05:35:32 PM »
Good job your here Terry or else the marketing boys would brow beat us with all those whiter than white claims :o

Quote
I very much like zero oversampling 1794 - and this implementation looks pretty good, but the measurements are a joke.
*any* DAC will do these measurements at 20Hz If they don't, the DAC is broken.
What you really want to see - is out of band noise > 20KHz. The out of band noise is very important.
As stated I think wideband (100kHz) plots with good resolution might be more meaningful.

Thank you for your enlightenment. ;) ;) ;)
V
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

tuyen

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Re: DDDAC 1794-NOS 24-192
« Reply #50 on: November 24, 2012, 05:46:20 PM »
 I thought any measurements, no matter how accurate they might be, are a joke around here ? :)

TRUST YOURS EARS!  (AND ENJOY YOUR JOURNEY)  :P  :P
« Last Edit: November 24, 2012, 05:49:58 PM by tuyen »

Offline kajak12

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Re: DDDAC 1794-NOS 24-192
« Reply #51 on: November 24, 2012, 10:42:13 PM »
I thought any measurements, no matter how accurate they might be, are a joke around here ? :)

TRUST YOURS EARS!  (AND ENJOY YOUR JOURNEY)  :P  :P
measurements are great for people that understand them no good for me just press PLAY
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline zenelectro

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Re: DDDAC 1794-NOS 24-192
« Reply #52 on: November 24, 2012, 11:19:49 PM »
I thought any measurements, no matter how accurate they might be, are a joke around here ? :)

TRUST YOURS EARS!  (AND ENJOY YOUR JOURNEY)  :P  :P

It's a tricky business - try to find a measurement that will tell you what the DAC will sound like.
I'm the first to admit they mostly don't correlate.

However, there are also so many BS measurements made up by people to substantiate their design.

I'm looking forward to great PC replay, one reason is that it will be possible to try a lot of
the different filters on the PC and see how much difference they do make.

T

Offline rhlauranna

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Re: DDDAC 1794-NOS 24-192
« Reply #53 on: November 24, 2012, 11:55:59 PM »
Well, from what I read there seems to be some severe sort of interest and potential and really deep knowledge and know-how around here which extremely surpasses mine (but I still have my ears - as many others), and you make me not only curious with your hints but also very pleased...

So, what do you think ? Would it be possible to concentrate and focus all your knowledge onto further developments, which all those who follow digital reproduction will need the one or the other way ? you really could show what you have on the pan but to argue a little bit here and comment a little bit there! I know you understand me right in the positive way...

During my hifi-life I came across two sorts of (interested) fans: the ones "barking like dogs" about everything (right or not, but always rather interesting) but always resting without any further practical results (I call them "the dreamers" - I can dream of everything, but what do I have in the end when I awake ? nothing ! absolutely nothing !!)

...and the other ones who more or less regularly came around the corner with concrete "results" whatsoever. With these there was always something on the table to be implemented, to be tested, to be listened to, to be discussed, to be judged... with all participants and interested... ooohhhh, what fun !!!! that was and still is the way we try to slowly but steadily move to develop things further...

and as I told already: the latest actual developments have reached such a high level of knowledge in every single area of our beloved HiFi that those who are able to practically contribute (the right way) get less and less... but that should not be... I read of so many superb practical results and ideas and knowledge here on the platform, that is simply awesome for me, so why not bundle and focus these on further ideas?

As I also told already at least a year ago this new DAC is "only" one step further in the line of developments which we want to do. And as we were not content with the results which one can buy even for a huge amount of money and running in big studios (no, I do not name them), we felt some sort of "urged" and got "obsessed" to do it ourselves, with - at least to our ears - "perfect" results (so far I have used the word "perfect" only two or three times in HiFi)...

well, fact is, that we (presumably all) still have not yet reached totally our aim. Alone from technical point of view there is at least one more (big) step to go, i.e. the development and optimizing of the handling of digital within the area of PC/MAC. And here are at least two things to generate from scratch:

1. the controlled (and of course noiseless, i.e. fanless) power supply with absolutely stable corresponding voltages and

2. getting rid of all USB or whatsoever computer-based norms and standards (which suit only their purposes and n o t  our AUDIO !)

some time ago some of you have already tried to contribute to this theme. And I have esteemed this very much, but at that time it simply was a little bit too early to follow. But now, time has come. So I very much would like to get you "pregnant" to further develop this theme. Any ideas and/or propositions ? Would be really great !!!
« Last Edit: November 25, 2012, 12:09:32 AM by rhlauranna »

Offline ozmillsy

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Re: DDDAC 1794-NOS 24-192
« Reply #54 on: November 25, 2012, 01:44:29 PM »
if not usb, what will you use,  spdif?

It's all about the music,, not the equipment.

Offline ozmillsy

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Re: DDDAC 1794-NOS 24-192
« Reply #55 on: November 26, 2012, 09:13:51 PM »
This is where delta sigma (aka PCM1794 / ESS Sabre etc) DAC's have dirty secret.
just 1 slight correction,  the PCM1794 is a dual format chip,  it has different inputs for PCM and DeltaSigma.

The dirty secret you speak of, is the delta sigma noise inherent with 1bit data.

I don't think this dddac is utilizing the DeltaSigma capability,  I believe they are using PCM only ?

Which isn't a bad thing, it means if we feed it a clean 24bit music file it shouldnt actually need any further filtering,  and in NOS mode the dac itself won't mess with it any further, just simply convert it.  I like the idea of that.

There is a fork in the road, and there is a choice to make.  

Do we pursue a DSD Dac, do it better than the other limited offerings available?  With this option, filtering is needed to clean up the dirty secret.

Or ,,,,,, do we pursue a 24bit or 32bit PCM hi-res solution?  With this option NOS mode is the way to go, I do agree with the way the DDD chaps have chosen to do it.

I think trying to do both formats, may not be ideal for either??

In either case, DSD or PCM, Reinhard is right,  half the puzzle is sorting out the "feed" of the data.

I was at Stevens a week ago.  Doug bought around his laptop, configured for music playback with Jplay,  out to Offramp,  into Killerdac.    It just didn't have the liquidity and clarity of the Wadia spinner into Killerdac.   Zen, I'm hoping your solution will get us there, as we're all sick of burning.
« Last Edit: November 26, 2012, 09:22:37 PM by ozmillsy »
It's all about the music,, not the equipment.

tuyen

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Re: DDDAC 1794-NOS 24-192
« Reply #56 on: November 27, 2012, 01:31:13 AM »
yeah oz, i think its doing pcm in.    more details here if zen can help interpret..  http://www.dddac.com/dddac1794_circuit.html

i like the dddac because it has a 'clean' and 'strong'  passive output signal.   my valve preamp  acts as a good refined 'valve output stage'  and volume controller.

i will be curious to see what zen comes up with for a high res dac/usb interface solution.

Offline ozmillsy

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Re: DDDAC 1794-NOS 24-192
« Reply #57 on: November 27, 2012, 06:55:16 AM »
That's actually very good information on the circuit design.  Well done to Doede for documenting it well.

If I'm reading it correctly,  the negative/positive balanced Outputs are combined to form the single unbalanced output.

Q I have is,  why not just leave the output as balanced?
It's all about the music,, not the equipment.

Offline dddac

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Re: DDDAC 1794-NOS 24-192
« Reply #58 on: November 27, 2012, 07:58:02 AM »
actually it does both... the capacitor output uses only one side of the dac, pos or neg... but both are available at the output. use two caps and you have a balanced output. or use both balanced outputs into a transformer and go single ended out, but utilizing both signals. by the way, the measurement section show clearly the balanced effect of d2 reduction

Offline zenelectro

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Re: DDDAC 1794-NOS 24-192
« Reply #59 on: November 27, 2012, 10:20:15 AM »
This is where delta sigma (aka PCM1794 / ESS Sabre etc) DAC's have dirty secret.
just 1 slight correction,  the PCM1794 is a dual format chip,  it has different inputs for PCM and DeltaSigma.

The dirty secret you speak of, is the delta sigma noise inherent with 1bit data.

I don't think this dddac is utilizing the DeltaSigma capability,  I believe they are using PCM only ?


Oz,

No it is a sigma delta DAC architecture.  It -has- to use sigma delta capability.

Lets go back to the start.

- 1 bit DACs:
This is equivalent of 1 resistor being switched from gnd to vcc (+3.3V).
The OP signal 'energy' is like a light dimmer, modulated time wise to have the appropriate signal level, then filtered.

- True multibit DAC (R2R):
R2R ladder network of resistors that allow (theoretically) 2^24 discrete OP current levels. There is no 'on time'
modulation.

- Multi bit sigma delta (Sabre and 1794 etc):
For simplicities sake, lets say 5 bit unity weighted. That would be 32 individual resistors of the same value
switched between gnd and vcc. The individual step level is 1/32 x true 1 bit, but they are still time modulated
to make the effective 'bits in between. They also use other tricks like DEM (dynamic element matching) to
randomly select those 32 resistors, turning any resistor mismatch / errors into noise. There's a lot more
to it but that's a very basic conceptual overview.

I believe Sabre has the highest number of discrete OP levels for a SD DAC, with something like 256 unity
weighted bits in 'stereo mode'.

So in the 1794's case, even when run in non oversampling mode without a digital filter there are
only so many OP bits that are switched on and off at very high speed to make up the true 24 bit
OP.

In fact, disabling the digital filter may well actually spread the HF, normally out of band noise closer
to the audio band. I'm not totally clear on this - hence my question WRT showing the extended
frequency plots - especially with 44.1 RB CD

Quote

Which isn't a bad thing, it means if we feed it a clean 24bit music file it shouldnt actually need any further filtering,  and in NOS mode the dac itself won't mess with it any further, just simply convert it.  I like the idea of that.


Yes - that would be nice but it doesn't happen. Any SD DAC needs to do 'time splicing' to get the effective bit resolution,
there's no free lunch. 

It's one of the reasons I was waiting for the next generation R2R DAC's - which got dumped. There's a lot to be said for
just a very good R2R DAC.

Quote

There is a fork in the road, and there is a choice to make.  

Do we pursue a DSD Dac, do it better than the other limited offerings available?  With this option, filtering is needed to clean up the dirty secret.

Or ,,,,,, do we pursue a 24bit or 32bit PCM hi-res solution?  With this option NOS mode is the way to go, I do agree with the way the DDD chaps have chosen to do it.

I think trying to do both formats, may not be ideal for either??


Trying to do both formats -right- certainly makes things more complex, no doubt.
The clocking and interface requirements are quite different.

Quote

In either case, DSD or PCM, Reinhard is right,  half the puzzle is sorting out the "feed" of the data.


That's no problem. I don't want to give too much away but the 'feed' is only part of the issue.
The end game is a) Complete isolation from source (PC) and b) absolute lowest jitter at the DAC.
DDD has made a very good effort but it is still some distance from absolute cutting edge and ticking all the
boxes.

Quote

I was at Stevens a week ago.  Doug bought around his laptop, configured for music playback with Jplay,  out to Offramp,  into Killerdac.    It just didn't have the liquidity and clarity of the Wadia spinner into Killerdac.   Zen, I'm hoping your solution will get us there, as we're all sick of burning.


Yeah, same, I'm mostly using PC sound card OP (emu1212) these days purely for flexibility - even though the quality is average.

OK - there's work to do and these posts don't get it done any quicker :)

cheers