The Soekris R-2R DAC: Technical Details
Feb 14, 2015 at 11:21 AM Post #16 of 251
I wouldn't sweat too much about the power supply - currently there aren't many ways how to mod the power circuits due to them being integrated in the board. A 7VAC trafo is sufficient.
 
Everyone currently has the power on/off issue, no way around it. The popping on Fs change is more troublesome.
 
Feb 16, 2015 at 1:57 AM Post #18 of 251
Keep in mind that this is with the stock filter set. At its best this DAC trounces my Stello DA-100 Signature. An acquaintance of mine who built the same 0.01% version rates it on par with a maxed out Buffalo III with both of them trading punches here and there.
 
Feb 16, 2015 at 10:08 AM Post #20 of 251
  Keep in mind that this is with the stock filter set. At its best this DAC trounces my Stello DA-100 Signature. An acquaintance of mine who built the same 0.01% version rates it on par with a maxed out Buffalo III with both of them trading punches here and there.


Wow! Par with the Bufalo III - that's using the Sabre ESS9018 right? Well certainly worth putting some time and effort into.  I like the fact it's upgradable - and so looking forward to upgraded filters in the future.
 
Already some great idea's for modding the board (from HiFiDuino):
 
  Replacing on-board PS capacitors
This one is endorsed by Soren [link]
If you insist to improve the on-board power supply, try replacing the 6 electrolytic capacitors with aluminum polymer types, 1000u 16V exist in same 10mm SMD footprint and t.ex. digikey stock them at $2.20 each. Should be easy to replace.
You can also add a small polymer electrolytic on the 3.3V output, but please note that the clock oscillator power already have a filter, so I doubt it will make any difference.
At this time I would be doing a standard installation before thinking of any other mod.

 
And:
  Snubbers on the transformer
The shouty sound can be somewhat tamed by filtering the power line and using optimal snubbers for the power transformer. (Check the Quasimodo/Cheapomodo threads for an excellent snubber measurement jig by Mark Johnson.)

 
Feb 17, 2015 at 1:22 PM Post #21 of 251
  +1 Thanks - you are correct.  I guess just the nomenclature of R2R. 
 
I think this is a good description - I believe is accurate:
Versus the regular Sigma Delta design - the newer Multi-bits S-D go along way to solving this - but introduce their own issues (on chip opamps).

 
I wonder how true that blurb about the sigma-delta chips was? Like pretty much all manufacturers are using sigma-deltas now, so they really can't fail that much in comparison to R2R. Not like it seems to say in that comment. 
 
Also, the other guy's build on hifiduino looks cool already. He's going along quickly and I look forward to reading his progress. I'm waiting for the first balanced output build, though. That's what I'd be looking at doing.
 
Feb 17, 2015 at 4:42 PM Post #23 of 251
   
I wonder how true that blurb about the sigma-delta chips was? Like pretty much all manufacturers are using sigma-deltas now, so they really can't fail that much in comparison to R2R. Not like it seems to say in that comment. 
 


Read the links I posted from MSB, 'Mother of Tone' and http://funwithaudio.blogspot.com/2012/01/today-in-electronics-everything-is-made.html.  They back up my 'blurb'.
angry_face.gif

 
And many of the best manufacturers are using R2R designs like MSB (see Platinum and Diamond DAC's), Bill Hobba's 'Killer DAC' and of course the TotalDAC.  All mentioned and linked to in the thread.
 
It helps to read the thread (it's only 2 pages) before commenting on posts and calling them blurbs.  BTW do you have any experience with R2R DACs or just spouting out your...
wink_face.gif
 
 
Also, the other guy's build on hifiduino looks cool already. He's going along quickly and I look forward to reading his progress

I look forward to you doing so as well
 
Feb 17, 2015 at 4:49 PM Post #24 of 251
  Gotto say - after swapping out the stock 44.1KHz filter this DAC improves even more.


Have you played with the spdif coax input 352k or 384k signal?
 
A friend and I are doing the build - his is further along.  We were able to get a lock at those rates over spdif coax.  And good output.  He had to leave and we didn't have time to play with it much.
 
Feb 18, 2015 at 1:54 PM Post #25 of 251
 
Read the links I posted from MSB, 'Mother of Tone' and http://funwithaudio.blogspot.com/2012/01/today-in-electronics-everything-is-made.html.  They back up my 'blurb'.
angry_face.gif

 
And many of the best manufacturers are using R2R designs like MSB (see Platinum and Diamond DAC's), Bill Hobba's 'Killer DAC' and of course the TotalDAC.  All mentioned and linked to in the thread.
 
It helps to read the thread (it's only 2 pages) before commenting on posts and calling them blurbs.  BTW do you have any experience with R2R DACs or just spouting out your...
wink_face.gif
 
 
I look forward to you doing so as well

If you had taken a VERY quick second to check my profile you'd see it listed plain as day that I used to have a Lite - DAC83. Though I know you know what that means, I'll clarify that this is indeed an R2R DAC, using 4x Burr Brown PSM-1704UK R2R DAC chips. And in fact, you and I have talked about this before, in the Gustard thread I believe.
 
When you clip me for not reading through a thread, which I have, does that mean I get to clip you for not remembering talking about something? And if you choose to say that you can't be expected to remember every post you've made, then I'll continue down the path of "how can you reference that someone should remember what they've read in a thread if you're not supposed to remember what you've said?". But that's all just snowballing if you'd continue down this line, which I doubt you'll do because it's pointless and petty.
 
 
 
Back to the thread:
 
Now, I think you're getting the wrong connotation, but hopefully not definition, of 'blurb'. I didn't want to say 'post' because it was a lengthy entry(post) with a lot of information. Calling it simply a 'post' sent the wrong message, as in it's brevity or shallowness. Calling it a blurb doesn't disqualify it, it was in fact quantifying it. I think that was the first problem and from there you missed what I was getting at.
 
You're right in the fact that some top tier DAC makers go R2R. I'm also quite aware of this and hear all the time about their greatness. However, just because Ferrari thinks naturally aspirated engines are best, does that mean Pagani's use of a turbo on the Huayra is wrong by default? It's the implementation and the entire package that, in my experience, determines the final result. The use of piece A vs. B contributes to the equation, no denying that, but doesn't define the result. And come on, I'm not talking about being dumb and making 1000% incorrect choices.
 
The issue I had, and that I have with any reviewer/commenter, is when they get into hyperbole with phrases like "has to be introduced in order to make them listenable". For the record, I got rid of my R2R DAC and now use a Wolfson WM8742 Sigma Delta based DAC and couldn't be happier. The entire implementation results in a DAC that is better in ever aspect than my previous one. BUT~
 
Given that I am sticking my nose in this thread, that I already said I'd subscribed to it, and that I was looking forward to the progress and feedback of the other forumer's results, I think you might gather that I'm more than willing to give this DAC a shot simply for it being an R2R DAC 
L3000.gif
beerchug.gif
 
 
I want this DAC to be a machine. Trounce everything out there, offer billion dollar sound for healthy DIY price. I want a 4x DAC board version, 2 per side, with balanced output. I want it to take a nice R-core for each side and another for the Amanero input. I want to explore a direct I2s input, such that I could use a modded Gustard U12. And I want all that to be cool and doable by me/anyone else who's interested in trying. 
 
So, let's look forward to the progress of this build, of the development of this DAC, and the progressive discussion of choices.
 
Feb 18, 2015 at 3:04 PM Post #26 of 251
  If you had taken a VERY quick second to check my profile you'd see it listed plain as day that I used to have a Lite - DAC83. Though I know you know what that means, I'll clarify that this is indeed an R2R DAC, using 4x Burr Brown PSM-1704UK R2R DAC chips. And in fact, you and I have talked about this before, in the Gustard thread I believe.
 
When you clip me for not reading through a thread, which I have, does that mean I get to clip you for not remembering talking about something? And if you choose to say that you can't be expected to remember every post you've made, then I'll continue down the path of "how can you reference that someone should remember what they've read in a thread if you're not supposed to remember what you've said?". But that's all just snowballing if you'd continue down this line, which I doubt you'll do because it's pointless and petty.
 
 
 
Back to the thread:
 
Now, I think you're getting the wrong connotation, but hopefully not definition, of 'blurb'. I didn't want to say 'post' because it was a lengthy entry(post) with a lot of information. Calling it simply a 'post' sent the wrong message, as in it's brevity or shallowness. Calling it a blurb doesn't disqualify it, it was in fact quantifying it. I think that was the first problem and from there you missed what I was getting at.
 
You're right in the fact that some top tier DAC makers go R2R. I'm also quite aware of this and hear all the time about their greatness. However, just because Ferrari thinks naturally aspirated engines are best, does that mean Pagani's use of a turbo on the Huayra is wrong by default? It's the implementation and the entire package that, in my experience, determines the final result. The use of piece A vs. B contributes to the equation, no denying that, but doesn't define the result. And come on, I'm not talking about being dumb and making 1000% incorrect choices.
 
The issue I had, and that I have with any reviewer/commenter, is when they get into hyperbole with phrases like "has to be introduced in order to make them listenable". For the record, I got rid of my R2R DAC and now use a Wolfson WM8742 Sigma Delta based DAC and couldn't be happier. The entire implementation results in a DAC that is better in ever aspect than my previous one. BUT~
 
Given that I am sticking my nose in this thread, that I already said I'd subscribed to it, and that I was looking forward to the progress and feedback of the other forumer's results, I think you might gather that I'm more than willing to give this DAC a shot simply for it being an R2R DAC 
L3000.gif
beerchug.gif
 
 
I want this DAC to be a machine. Trounce everything out there, offer billion dollar sound for healthy DIY price. I want a 4x DAC board version, 2 per side, with balanced output. I want it to take a nice R-core for each side and another for the Amanero input. I want to explore a direct I2s input, such that I could use a modded Gustard U12. And I want all that to be cool and doable by me/anyone else who's interested in trying. 
 
So, let's look forward to the progress of this build, of the development of this DAC, and the progressive discussion of choices.

 
Ok fair enough!  Which DAC did you get to replace the DAC83?
 
I have had about 11 different DACs of both designs - right now I have 3 and I'm building a 4th - this one.  To me the R2R DACs sound better - for less money.  I respect manufacturers like MSB and TotalDAC, and modders/builders like Bill Hobba.  I love my APL DAC - from what I can tell Alex has utilized the multisegment 32-bit AKM very well - using them in a 6 DAC per channel configuration.  I still think the modded LIte DAC60 has a better tonality.  Soon to be getting better Mundorf Supreme Gold/Silver Oil Caps - just to see how far that unit can go.  And it's 1/4 of the cost of the APL.
 
So back to the thread - I'll be looking forward to seeing your Soekris build project.  When's you board coming - or do you have it already?
beerchug.gif

 
Feb 19, 2015 at 12:44 PM Post #28 of 251
  This look promised enough....I guess I will saving for this, my Geek Pulse takes forever to ship....


Geek Pulse - Wow nice piece of gear!  Have you heard his custom made R2R? 
 
From their website:
 
 
The History of Pulse Headphone Amplifier
h5_border-bottom.jpg
Back in 2009, Larry was on a quest to promote the importance of high-resolution audio. He had been building the first 32 bit/384 kHz bit perfect resistor ladder DAC, and so he was traveling to speak who anyone who would listen, which included a visit to Intel, one of his first investors, and International CES in Las Vegas.
At the time, he was demonstrating his DAC using a headphone rig. He'd chose the HD800 over-ear headphones from Sennheiser as his reference, but he couldn't find a headphone amp with a wide enough bandwidth to reveal the beautiful nuances of 384 kHz digital music; nor could he find an amp with enough power to effortlessly drive his big cans. He needed a fully-balanced, dual-mono amp with a DC coupled, non-negative feedback output. And since he was demoing 384 kHz music, he needed a bandwidth of at least 200 kHz.
He couldn't find such a beast, so he built it himself.

 
Feb 19, 2015 at 5:34 PM Post #29 of 251
Another great DAC maufacturer making R2R DACs - Audio-gd Reference 10.2 DAC
 
http://www.tonepublications.com/macro/audio-gd-reference-10-2-dac-and-more/
 
Mention multi-bit in the right company and words such as ‘analogue’ and ‘smooth’ get bandied around.  A surge in delta-sigma implementations means that such multi-bit DACs are beginning to fade from mainstream consciousness.  Whilst the audible magic isn’t just in the chip itself – there’s power supply and output stage to consider – there might be some truth to the superior ‘rightness’ to DACs that sport, say, a Philips TDA1541 or a Burr-Brown PCM1704. 

Audio-gd’s (8 x PCM1704) flagship Reference 7.1 DAC still wows with snap-attack micro-dynamics and tonal beauty; something that often eludes many delta-sigma designs, especially at sub-$1000 price points.  Delta-sigma chips are presumably chosen by manufacturers for their lower production-cost impact and on-silicon extras (e.g. up-sampling, filtering, volume control).  Audio-gd has infiltrated this space also. 

 
And well received model 7.1
http://www.digitalaudioreview.net/2011/04/audio-gd-reference-71-dac-8-x-pcm1704uk/
 
Feb 24, 2015 at 6:58 PM Post #30 of 251
And yet another top DAC manufacturer making a near SOTA R2R DAC:
 
http://www.6moons.com/audioreviews2/aqua/1.html
 
 
Of the remaining options they consider Burr-Brown's legendary 24-bit PCM1704 available in U, J and K grades the ultimate conversion IC. Thus they prefer it to Texas Instrument's current ΔΣ PCM1795 replacement and the vintage Philips TDA1541A and Analog Devices AD1865 R2R chips. Needless to say, Aqua's flagship valve-hybrid La Scala MkII gets the 1704 in top K selection.

 

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