Downside to R2R Ladder DACs?

Really! I have two R2R DACs that either are 20 years old or uses DAC chips that are from the era of highly praised chips from Burr Brown and  Phillips that sound "pristine" with no change in their performance at all. So, your sales person is giving you a bunch of BS, in my opinion. Question, does he only sell Sigma Delta single bit DACs, if that's so that might explain is unfounded assumption regrading R2R based DACs.

30 year audio professional really high quality resiseors wont drift you are mutch more likely to hav a problem witha cap or ic

Assuming the R2R DACs were built with genuine fine tolerance resistors this is utter nonsense.

A sales person I generally trust told me to steer clear of used R2R DACs, since their reliance on high precision resistors causes them to sound best when new, and degrade fairly quickly.

All I can say is, typical sales persons BS to get a sale on something else.

@abraxalito while your here, been playing around with an old Arcam Alpha Plus, with it’s TDA1541 just using opamp I/V’s for now, what do you think of all the specs on the LME49710 (1.2μs to 0.1% settling time and insane distortion figures also) as one sounded dam good to me when I tried it.

Cheers George

@georgehifi these days I wouldn't use a 'naked' opamp in I/V without prior filtering unless it was a pure video part (AD811 for example).

@abraxalito, think I have some of them laying around, do you know if they're unity gain stable, no mention in the data sheet.

Cheers George
 

@georgehifi Its not a drop-in for normal opamps because its CFB. I get better results using a passive filter before my opamps than I did with AD811 and no filter. AD829 is doing very nicely as I/V for me at present, preceded by a filter.

...steer clear of used R2R DACs, since their reliance on high precision resistors causes them to sound best when new, and degrade fairly quickly...

I think your sales person is trying to sell you a new DAC.

My R2R DAC is a Theta ProBasic III that is more than 20 years old. I love the thing as it does it does not have that treble edge that one hears in so many "modern day" DACs.

Listed new for $2,700 and I bought used about three years ago for $600.

Thanks for listening,

Dsper

At therisk of being contentious: Aggressive treble is more a sign of poor clocking than a design fault of delta sigma dacs compared to r2r dacs. Even highend dacs benefit from reclocking with Mutec, Cybershaft, Antelope, sotm et al. There is no superiority in r2r dacs, they tend to be more euphonic but sometimes less resolving. YMMV

@cheeg the section labeled "Oven Control" in the Lavry DA924 user manual may be informative. The DA924 (DA2002 for consumers) was often considered a "gold" standard in professional audio DACs and not just for its color.

The specific sentence relevant to your question is:

The PCM DAC is constructed of custom made laser trimmed thin film resistor networks; yet any resistor is subject to short term drift due to temperature variations and long term drift due to component aging.

bs meter from that salesman just hit 100

suggest u trust him less going forward

Just to chime in on salesmen BS... I recently had this salesman suggest I’d buy his Audiolabs MDac because the other DAC I wanted to try out somewhere else was sounding worthless. The DAC I was talking about was the RME-ADI 2 DAC...

DAC designers have more than a passing knowledge about resistor load stability and incorporate end of life tolerances in their designs when choosing the initial or purchased tolerance. In other words, they listen and evaluate before they put it on the market.

Since we are an audio manufacturer that builds DHT R2R dacs, this is absolutely false.  That would mean every component would have the same issues since everything has resistors in them.

Dump that sales person.

There is no superiority in r2r dacs, they tend to be more euphonic but sometimes less resolving. YMMV

That all depends on the design of the DAC.

Not true at. All , a quality resistor such as what you see in amplifiers, preamps last for decades, capacitors wear out before resistors , resistors control resistive values and dissipate very little 
heat especially in digital where it is low voltage .i have modded for over 20 years ,just think. How many years you may have Held
onto a a piece of electronics And it still works I have tunes 30 years old still working and quality resistors just  keep doing their job ,look at Vishsy naked resistors for example less then .5 watt
and rock solid used for years and tolerances on average well under 1%, if matched by the hundreds better still and won’t drift for many years wear a capacitor is constantly changing a resistor 
is a constant. I had a AbN 1704 R2R  dac for over 15 years sold it and still working .

Thank you all for your responses. ITT is reassuring to hear that many of you have had good results with your ladder DACs, but those who compare this situation with normal circuit aging issues are missing the point. The reason why resistor degradation could be much bigger issue in higher quality R2R DACs is that the algorithm used to design them demands extremely tight tolerances in resistance value to achieve a small improvement in sound. For example, the Denafrips Terminator specifies resistance values of 0.005%, and 0.02% is common in less expensive designs. In amps and preamps, a drift of 1% in resistance is usually not audible; in a ladder DAC, it would make a huge difference. As stated in @nekoaudio’s post, the Lavry DA924 user manual notes that even custom made laser trimmed thin film resistor networks are “subject to short term drift due to temperature variations and long term drift due to component aging.“ Clearly, the potential is there for R2R DACs to degrade faster than other designs; I’m curious whether any Agoners have experienced this firsthand?

Hi,
I have A/B tested 89 different DACs and your sales persons is just selling you. R2R DACs are my favorite and I have never heard any of them deteriorate with usage.

Cheers,

Sitting here listening to a pair of PCM-63K's in my 25 year old Dac and things sound better than ever. I concur with above sounds like salesperson agenda BS.

As several people responded here that they’ve had their R2R DACs for decades and still love them, I think you have your answer.  

no soix...

the dacs have worn out resistors, and the owners have worn out ears!!!!!  HAAHAHAHAHAHA

Laser trimmed resistors on the same substrate tend to have similar tempco and aging.  While aging can change initial resistance it is very likely to do it in similar fashion (same material) to all resistors keeping division ratios pretty much the same.  In addition, the largest changes in any resistor are just right after production.  Older resistors change very little.   There is an assumption that non Delta-Sigma DACs are R2R - not necessarily so and many of them have self calibration mechanism. Mentioned Philips TDA1541 is R2R but only for the 10 highest bits while lower 6 bits are controlled by Dynamic Element Matching (DEM), based on emitter scaling 10-bit current divider.  It is possible to have resistor ladder, current scaling, voltage scaling and charge (on capacitor ladder) based DACs plus combination of them in multi-bit converter. 

Even if we forget technical reasoning - IMHO only insane company would design a chip that shows sound deterioration after 10, or even 20 years. 

I don't know much about R2R Dacs of 10 years ago,but when I see the inside of a Denafrips R2R Dac with over 400 capacitors I wonder more about the sound impact of any number of those caps going bad over time, and by time, I mean the general time most "audiphiles" get the urge to change caps in their respective equipment. 

You all are a great resource — thank you so much!

I don’t know much about R2R Dacs of 10 years ago,but when I see the inside of a Denafrips R2R Dac with over 400 capacitors I wonder more about the sound impact of any number of those caps going bad over time

It’s very good for power supplies, as many small cap have far lower ESR (google it) than one or two big caps of the same uF.
The energy release for transients is far quicker with lower ESR. The same now is happening for power supplies in poweramps of the higher end ones.
Look at these in my 2 x amps, if you look close there are 2 cap stacks per channel
https://ibb.co/cQXGW1F
https://ibb.co/2WbJc5k
https://ibb.co/h9b4T0X


Cheers George

George, this is very true - two power supply caps in parallel have smaller ESR, but they also have smaller inductance, often horrible for very large caps.  In addition few smaller caps instead of one large cap allows for better packaging (more efficient use of space).

Point made by hrabieh is very good - DAC is not only D/A converter but far more.  There are many DACs based on the same D/A chip that sound differently and have different reliability.  

George, this is very true - two power supply caps in parallel have smaller ESR,

And it’s great we can access cheap ones from our little Chinese buddies who make them complete ready to go at what just our parts cost would be. Many more variation on this theme in ebay voltage and capacitance.
https://www.ebay.com.au/itm/DIY-kit-62cps-Nichicon-330uf-100V-Array-Power-supply-kit-for-Power-amp-D...

Cheers George

R2R DACs are dependent on the accuracy of the resistors. Therefore if a particular design has a long term problem with one or more resistor values changing (absolutely or relative to the other resistors), then the DAC will be degraded. I suspect that unless the degradation is gross, most people would not hear the difference with normal music at normal listening levels. So saying "my 20 year old R2R DAC sounds great" is probably not a valid test! However, the degradation would be measurable and that would be a valid test. If this was a common, significant problem, I would expect there to be a lot of published engineering articles demonstrating it, but I've not stumbled on anything yet.

cheeg your dealer doesnot sell any high quality R2R dacs 
that’s why all the misinformation a Lampizator, msg, Aqua ,
Denafrips .and and a bunch of otherbrand name  dacs made Today Are excellent . Waay too much misinformation .
it all comes down to the engineering and implementation 
of the design,your dealer is Totally bias ,I learned 40 years ago 
never put all your eggs in one basket ,there are a Many dealers online !!

Plenty of electronic components will drift over time.  You probably won't hear it s it is gradual.  In direct comparison if you had a time capsule and kept a new one 20 years later to compare, you may be able to hear the difference.  Not all R2R boards are the same so a general statement is that it won't be a factor.  Is your salesman saying that a chip set won't also degrade or drift over time?  Well at least you will be enjoying your music more until that time comes!

Happy Listening. 

HI
I just bought a BODER PATROL SE I connected with a sonore optical module connected to a silent angel Z1
The DAC ( I change the tube with a mallard and the fuse with a synergistic orange) for les than 2000USD is absolutely fantastic much much better than my Meitner I owned
It is a R2R emotional DAC with a lot of energy
I cannot stop now listening my room library  so addict
bertrand

@berti For some reason I can’t message you directly from your profile. Would you mind sending me a PM regarding your findings with BP vs Meitner?  Which Meitner DAC did you own?  How old?  How would you characterize the two sounds?  I have an Emm labs/Meitner that I am trying to replace and any thoughts on yours compared to BP would be much appreciated. I personally find the emm labs to sound really good but it is limited by sampling rate. To me it seems a bit bright and thin but I wonder if it is my speakers or the DAC. Thank you in advance if you would be willing to share your thoughts in a PM. 

@cheeg, that salesman you trust is untrustworthy.  Move on.

I have an ancient Wadia 15 that only plays redbook. Uses the famous Burr Brown PCM63 and sounds wonderful. If there has/had been drifting it still managed to outperform a bunch of DACs in our local shootout. One of these was the well known Yggdrasil which although very detailed did not provide the boogie and foot tapping. The decision was unanimous, all preferred, on redbook only, the Wadia to that Schiit  :)

So drifting resistors or drifting clouds or whatever, the message is use your ears.

I think in future when my wife wants to know which DAC we'll be using, I can say "play it through the 'drifter' my dear.