Author Topic: DDDAC 1794-NOS 24-192  (Read 174864 times)

Offline zenelectro

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Re: DDDAC 1794-NOS 24-192
« Reply #60 on: November 27, 2012, 10:42:27 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?

Oz, (briefly)

I'll refer to PCM1794 in general and leave DDD to comment on that specific implementation, this seems most appropriate.

1794 shows very low distortion in each DAC OP phase, with increasing H2 (2nd harmonic) as the voltage swing increases.
With 1794 running into a virtual ground, there's not much in it. So as you allow more voltage swing at the DAC OP, you
get some more H2 creeping in, which will be largely cancelled when using both phases.

From tests I've seen elsewhere, you need about 100R per phase (stereo) to get any significant H2 happening and we
are still talking really low amounts. In fact running mono and into a virtual ground, the distortion artifacts look like
being close to any measuring equipment currently available.


Offline springcreek

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Re: DDDAC 1794-NOS 24-192
« Reply #61 on: November 27, 2012, 12:44:51 PM »
I've chatted a few times with Benjamin Zwickel of Mojo audio who sells modified mac mini based music servers and an R2R DAC based around the AD1865 chip.

http://www.mojo-audio.com/d-a-converters/

Here are some of what Ben had to say. Ben seems like a very nice fellow.

Hi Andy,
 
Well it seems we have similar paths.
 
Prior to starting Mojo Audio I was doing non-oversampling conversions and upgrades to "heavyweight" TDA 1541 DACs with CDM and BU1 transports. I could take a $400 used CD player from eBay and put $200 in parts into it and have something that would blow away anything I'd heard in a modern audio salon showroom. I was selling these upgraded vintage decks all over the world.
 
Name the "whose who" vintage deck: Revox, Philips, Marantz, Sony, etc and I've likely either upgraded it, owned it, or both.
 
So when I tell you our media sever will give you literally DOUBLE the digital resolution of your transport you know I'm speaking from experience. I also believe you will appreciate where this higher resolution is experienced - in better time, tune, tone, texture, musical flow, and emotional content.
 
You won't believe you are listening to the same system.

Hi Andy,
 
I can't say that you're too far off with everything you wrote.
 
Personally I find most digital reproduction, especially the modern HiRes stuff, to sound like what a computer thinks music should sound like as opposed to music.
 
The more "advanced" they get the clearer, cleaner, more dynamic, more extended, and more transparent they sound but the less emotional content and musical flow they actually have.
 
I'll let you in on a little secret: sampling or playing back anything over 20-bit is theoretically impossible due to the noise inherent in any system.
 
The ONLY reason they are using 24 and 32 bits is that the more "data" they throw at the cheap single chip "closest approximation" single bit modern DACs they are using the better their algorithms can give the illusion of error correcting in real time.
 
The fact is that no algorithm can tell the difference between "errors" and "emotional content" so what they do is "homogenize" the music making it a clean, dynamic, and extended computer's interpretation of music as opposed to reproducing the actual music in the recording.
 
I consistently blow minds at audio shows playing any old ordinary 16-bit recordings through my digital front end where my competitors are playing HiRes and customer after customer tells me how much more "musical" and "emotional" and "analog like" my system sounds.
 
Don't even get me started on how noisy and crappy sounding most power supplies are.
 
The only way I've found for digital reproduction to sound musical is to use non-error correcting, non-oversampling, non-upsampling ordinary 16-bit digital files played back on a classic R/2R DAC.
 
Considering how many companies are still manufacturing modern non-oversampling R/2R DACs using vintage DAC chips I must not be alone in this belief.
 
In order to get a whole other layer of error-correction and noise out of the way our media servers provide a near bit perfect digital source.
 
I always tell my customers: "if it doesn't come from the source, it can't come out of the speakers."
 
That being said, a proper media server is the most important part in a "musical" sounding digital audio system.
 
If the bits are not stored and transferred correctly there is no way that any component farther down the signal path can correct the damage done at the digital source.
 
As for interfaces like touch screens and iPads, you can use ANYTHING that is either Mac or PC compatible. I have a small touch screen that I used at shows like RMAF that works quite nicely but the best sound would be from a "headless" or "monitorless" system where it is controlled by an outside device like an iPad, smart phone, or other computer.
 
Once you hear our media sever you will likely want to hear our NOS R/2R AD1865 DAC.
 
Let me know if you have any questions.


Offline springcreek

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Re: DDDAC 1794-NOS 24-192
« Reply #62 on: November 27, 2012, 12:49:45 PM »
It would be neat if such a server actually gave us what we want instead on relying on old clunky/cranky transports.

I know my wife would be much happier with a PC based system run off an iPad. Lets hope we can get there soon.


tuyen

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Re: DDDAC 1794-NOS 24-192
« Reply #63 on: November 27, 2012, 02:11:10 PM »
Hi Andy,

If you are intersted in a AD1865NOSK chip DAC, I can get a one off Core Audio Tech Kuma NOS DAC  for $1200 or nearest offer.

Uses Oscon SEPC and Mundorf Electrolytics along with V-Cap TFTF output coupling caps. The V-caps alone are worth more than the sale price of the DAC.

Offline ozmillsy

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Re: DDDAC 1794-NOS 24-192
« Reply #64 on: November 27, 2012, 09:36:23 PM »
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.
Well, for some reason I thought the 1794 was an R2R, and was doing an internal conversion from dsd to PCM, before the Dac step (when handling dsd input).  

My mistake.  

I don't think it's practical to bypass the filtering on sigma delta dacs,  but I don't really know.  It just doesn't seem right.


Quote
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.
  I guess the R2R king is the 1704 ?

Not that I'm suggesting that is the path to take.  But I do like the idea of R2R in NOS mode.

I remain open minded to all the options.   It's complex.....

Quote
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.
I consider A/B to be all part of the feed.   Ie: the reading of the data, and transporting it to the Dac chip,  is all part of it.

All interesting discussions.    And no Reinhard, we're not barking dogs.
« Last Edit: November 27, 2012, 09:40:09 PM by ozmillsy »
It's all about the music,, not the equipment.

Offline kajak12

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Re: DDDAC 1794-NOS 24-192
« Reply #65 on: November 27, 2012, 09:39:58 PM »
It would be neat if such a server actually gave us what we want instead on relying on old clunky/cranky transports.

I know my wife would be much happier with a PC based system run off an iPad. Lets hope we can get there soon.


Springcreek what usb to spdif does he recommend?
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline kajak12

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Re: DDDAC 1794-NOS 24-192
« Reply #66 on: November 27, 2012, 09:42:25 PM »
It would be neat if such a server actually gave us what we want instead on relying on old clunky/cranky transports.

I know my wife would be much happier with a PC based system run off an iPad. Lets hope we can get there soon.


Ipad :o :o crap i dont have one i think my cd94/zenclock is safe for time being unless macmini can do wonders but $$$ investment is needed for a lesson
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline springcreek

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Re: DDDAC 1794-NOS 24-192
« Reply #67 on: November 27, 2012, 09:47:54 PM »
Thanks for the kind offer Tuyen  ;D

I am intrigued about these products and Doede's dacs and I'd love to hear them. I really hope this technology can deliver The musical goods and integrate into our lives, sure would make my wife happy.

I may well get a server next year like Ben makes and compare to a tricked out CD94. We may well learn something from it. If it's not as good at least my wife will like it and that can only be a good thing  ;) might have to get two inputs on my dac.

I'd rather not use a clunky transport but will if it gives me what I want from the music. I continue to follow this thread and your system with great interest. Hopefully I can get to WA to here it and Mario's one day. Looks like your enjoying the journey

Cheers, Andy
« Last Edit: November 27, 2012, 09:54:55 PM by springcreek »

Offline springcreek

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Re: DDDAC 1794-NOS 24-192
« Reply #68 on: November 27, 2012, 09:56:59 PM »
It would be neat if such a server actually gave us what we want instead on relying on old clunky/cranky transports.

I know my wife would be much happier with a PC based system run off an iPad. Lets hope we can get there soon.


Springcreek what usb to spdif does he recommend?
Hey Mario

Not sure mate, he just said there were some good options available.

If I get one I'll send it to you for a listen. 8)

Offline springcreek

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Re: DDDAC 1794-NOS 24-192
« Reply #69 on: November 27, 2012, 10:01:52 PM »
I had a quick look at the Core Audio site and it looks like they use digital amps with field coil lowthers  :o

I would have thought that would be an awful combo. Love the look of those FC lowthers, would go well is one of Martin's front horns  ;D

Hey T hopw are the bass horns coming along? Martin sent me the plans, really got me thinking...I looove horn bass, seems like other bass arrangements blunt the transient...not enough whack!

Too much gear to try...so few $$$  :)

Offline kajak12

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Re: DDDAC 1794-NOS 24-192
« Reply #70 on: November 27, 2012, 10:07:36 PM »
I had a quick look at the Core Audio site and it looks like they use digital amps with field coil lowthers  :o

I would have thought that would be an awful combo. Love the look of those FC lowthers, would go well is one of Martin's front horns  ;D

Hey T hopw are the bass horns coming along? Martin sent me the plans, really got me thinking...I looove horn bass, seems like other bass arrangements blunt the transient...not enough whack!

Too much gear to try...so few $$$  :)
Digital amps :o :o :o :o  timbre,texture,tone where ????  bloody hell no idea
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline ozmillsy

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Re: DDDAC 1794-NOS 24-192
« Reply #71 on: November 27, 2012, 10:08:28 PM »
Andy, what happened with the BLH boxes?  Have you tried them yet?
It's all about the music,, not the equipment.

Offline kajak12

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Re: DDDAC 1794-NOS 24-192
« Reply #72 on: November 27, 2012, 10:09:31 PM »
It would be neat if such a server actually gave us what we want instead on relying on old clunky/cranky transports.

I know my wife would be much happier with a PC based system run off an iPad. Lets hope we can get there soon.


Springcreek what usb to spdif does he recommend?
Hey Mario

Not sure mate, he just said there were some good options available.

If I get one I'll send it to you for a listen. 8)
send it to steve its closer  ;)
still discovering the link between electronics and audio reproduction.so much to learn and so little time

Offline springcreek

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Re: DDDAC 1794-NOS 24-192
« Reply #73 on: November 27, 2012, 10:20:41 PM »
Andy, what happened with the BLH boxes?  Have you tried them yet?
Hey Oz
No Paul has them, I took one look and knew they weren't coming to my place. My wife would flip if I brought in even more big ugly piles of chipboard  :o

Would love to try BLH boxes though...might try building a set that look a little nicer. My speakers are ugly enough now...though I love them...they make me happy  ;)

Offline ozmillsy

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Re: DDDAC 1794-NOS 24-192
« Reply #74 on: November 27, 2012, 10:36:52 PM »
I did warn you they weren't pretty.   
It's all about the music,, not the equipment.

Offline springcreek

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Re: DDDAC 1794-NOS 24-192
« Reply #75 on: November 27, 2012, 10:40:20 PM »
Ha yep I was warned  ;)

tuyen

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Re: DDDAC 1794-NOS 24-192
« Reply #76 on: November 28, 2012, 01:06:28 AM »
Hi Andy,

Most welcome if you ever stop by WA.   Doede's designs are excellent.  Well designed, fun to build, not silly priced, reference-level performance in my opinion.  The 120 chip paralleled TDA1543 DDDAC1543MK2 with the USB module was my fav DAC for long time.    This new hi-res usb dac he has designed plays on same level for 16/44 files. Hi-res recordings add that extra layer of fidelity that is quite enjoyable.

From my own testing, I felt USB via pc transport has already surpassed the performance of disc spinners long time ago. Hence why I decided to move on all my disc spinners.  Isn't it funny how there seem to be 2 separate groups. One who has moved to computer based transport because they feel it it brings sonic improvement.  The other group finding the disc spinner still sounds best and computer transport still has long way to go...     both groups listening to same music.    which group is deaf? or should i say, which group is more deaf then the other? :)

Me personally, I think I'm lucky to be in the first group. As using computer transport also includes the much-important convenience factor, without having to feel that I am compromising on sound quality :)
 
Re the bass horns: Nearly done. Probably 1 weekend of work/beer to go before we be rocking.   Indeed,  nothing like bass notes between 50-300hz through a front loaded horn hitting ya ears and body. The speed and scale of transients are pretty crazy.   Reinhard was right all-long about bass horns being the final frontier with regards to 'doing' horns.
« Last Edit: November 28, 2012, 01:49:26 AM by tuyen »

Offline ozmillsy

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Re: DDDAC 1794-NOS 24-192
« Reply #77 on: November 28, 2012, 07:14:35 AM »
.  The other group finding the disc spinner still sounds best and computer transport still has long way to go...     both groups listening to same music.    which group is deaf? or should i say, which group is more deaf then the other? :)

Haha, very good T.  Actually reminds me of the demo with Doug last week.  

We ran his laptop via Offramp into a new model KDAC,  then we put the same music onto the Wadia/KDAC.

Steven said "well it's no contest is it", and Doug says "yes, I prefer the laptop".   A very funny moment to be in the room, observing.  :)

Neither is deaf.   I think it's simply a matter of perceiving different traits/qualities, and being accustomed to them.  With familiarity comes an appreciation of the strengths.

    For me, I can understand both points of view.   I did feel that the laptop/Offramp seemed to be slightly more detailed, and the Wadia more liquid and relaxed.     Which is more 'natural'?   I don't know, and it doesn't really matter, because we're now in the realms of personal preference.

Oh, and the comparison is also slightly flawed, in that both digital feeds were via spdif.    We really need to compare I2S, IMHO.   As spdif out of my CD94 has a slight haze to it.   I hear more clarity and details via I2S.

I like to think I've invested a significant amount of time and energy into computer based sources,  and I haven't lost hope that there will be a computer solution in due course that appeals to me more in SQ than my spinner.
« Last Edit: November 28, 2012, 07:18:36 AM by ozmillsy »
It's all about the music,, not the equipment.

Offline vitavoxdude

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Re: DDDAC 1794-NOS 24-192
« Reply #78 on: November 28, 2012, 11:31:36 AM »
 :D Ha, yes back to the issue of transports.  Well at the mo I still believe that for 16 bit the silver spinners in the form of the CDM1 via I2s has it by a neck for naturalness and a sense of real performers happening in real space with good recordings.  PC based via USB sounds artificial but when taken to higher resolutions sound good but as yet no cigar.  I can live with either but still have a preference for the silver disc as it feels like a worn in pair of slippers compared to a new pair of tight shiny leather shoes. Detail per se is not the full picture although attractive initially becomes quickly wearing particularly in the higher frequencies.
 
I am happy that there are some who continue to plunge into the unknown in the quest for ever better replay as they save me money. ;)  Once solid state replay units have finally come of age and the music industry gets behind the latest and greatest you can be sure they will try and convince us all to buy our whole back catalogue tout suite.  Memory cards are now cheap enough to be the new music carrier and it is easy to maintain the retail trade this way, hi res downloads fails to keep music shops in business and has the risk of HDD crash and die scenarios which most currently ignore.

Hi Res downloads are great quality wise but come at a fair premium over regular 16 bit and then it's downhill trying to get it off the SSD with minimal degradation.  I feel sure that many here will be keeping a weather eye on new developments hoping to find a new wardrobe for the kings new clothes and people like our own Zen Electro may eventually get closer to cracking the timing issues with PC's as he has with silver disk spinners, letís all hope so.  ;D
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.

Offline ozmillsy

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Re: DDDAC 1794-NOS 24-192
« Reply #79 on: November 28, 2012, 06:42:36 PM »
and has the risk of HDD crash and die scenarios which most currently ignore.
I don't ignore it,  it's a significant risk, and costs me a fair whack to mitigate.   I have terabytes of SACD iso and DVDA rips stored, that took me hundreds and hundreds of hours to backup.  Stored on expensive NAS with raid redundant discs. But that isn't enough, also have offsite copies.

Quote
Hi Res downloads are great quality wise but come at a fair premium over regular 16 bit and then it's downhill trying to get it off the SSD with minimal degradation. 
Not sure what scenario you mean here V.   Downloading has error checking built into the protocols, to ensure what you get is bit perfect (in terms of duplication).   Curious if there is another scenario I'm not thinking of, that has flaws.

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