R2R DACs vs. chip DACs vs. FPGA DACs

This is mostly for Ted, as I am curious to understand the different methods of Digital to Analog conversions, namely using a chip, FPGA programming like DS (which to me is like the chip, but proprietary programming and updateable), but now there are some very good reviews of R2R DACs like Denafrips, which seems the most analog solution to conversion, and how it used to be done, but I don’t understand it well so appreciate some explanation and pros/cons versus other solutions!

All DACs need a low pass filter to not generate all manner of inharmonic distortion. But a single bit DSD based DAC doesn’t need anything else.

For a 20 bit DAC a thermometer resistor DAC would use about a million very precise (1 part in a million) identical resistors. Not practical :slight_smile:

An R-2R resistor DAC uses two resistors per bit, but the also needs to be accurate to within one in a million for a 20 bit DAC. There are a lot of tricks to do a better job, but fundamentally accuracy is hard.

You can build a great DAC in a lot of ways. But a great ladder DAC isn’t simple and quality costs just like other kinds of DACs.

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I am sorry but I don’t understand this sentence. Is there a low pass filter in a DSD based DAC or not…?

The only analog thing a DSD DAC needs is a lowpass filter. I was just reminding the OP that fundamentally a DSD DAC is the simplest possible DAC from a design/implementation point of view: getting the single bit bitstream from a PCM input isn’t trivial, but it’s not hardware.

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Got ya… Thx…!

Darko’s review of the Denafrips (He loves his DS, his Chord Dave is on headphone duties upstairs) talks about how the Denafrips and the DS are different “flavours” and which one you might choose (and maybe prefer) can be dependent on system synergy: i.e. what the rest of your kit is.

Also,
He gave a shout out to the Directstream’s FPGA firmware upgrade ability, John’s currently on Redcloud.

Trust his reviews, he’s a “real world” audiophile and many different dac’s have crossed his path, and he still uses his Directstream in his main system.

In his system, he preferred the flavour of the Denafrips, but theres a million and one variables (including his personal taste) that factored into that.

There’s no absolute “best” for everyone really, pick your flavour and be happy.
I know though that the DS is the best Dac I’ll ever hear…preferred it to various DCS dacs I’ve heard at high end shows but never heard one in my room with the rest of my equipment!

Know what I’m saying?

Oh…and John Darko was still on Redcloud. :wink:

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Thanks Ted. That makes sense now why Denafrips DACs are priced per their resistance Accuracy which range from 0.01% , to 0.005% precision resistors!

Seems like most rate DS as having a warmer more laid back sound. Maybe “more analog” sound? Wonder why is that? Like he said if you have a more revealing speaker DS maybe a better match versus a more laid back speaker could benefit from Denafrips

At the time of Darko’s video review of the Terminator in October, Snowmass had not be released so he was current on firmware.

Hi Ted,

I’ve read in several places of e.g. why doing r2r is tricky/costly, other comments that they have high distortion, and perhaps not suitable for mass production, etc. On the other hand, I’ve read rave reviews of a number of different r2r DACs and that there is something different/better/special about them. There are a number of r2r products including MHDT labs, Densfrips and Total DAC to name a few.

For the most part, class D amps don’t sound like Class A (or tube) amps no matter what you do. Is there something fundamentally different in the sound of different classes of DACs?

Thanks for your time.

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I think, if you ignore cost, there are many ways to build great DACs. I also appreciate designers who push an idea to the limit because they believe in it. R-2R DACs take work to get near the linearity of many current DAC chips, but many people seem to like the sound of R-2R DACs. I suspect some of that is actually due to differences in the design of any upsampling and/or other digital processing (if any.)

I’ve only heard one R-2R DAC (that I know of (except for toy versions I’ve built) ) and it sounded good.

My experience is that DACs (heck, whole systems) that are transparent seem to converge on the same sound as they are refined, that’s not suprising, it’s sort of the definition of being transparent. For people who listen to more select kinds of music, big bucks can be saved by compromising on the production of things that aren’t there in the music, or things that certain listeners just don’t hear or don’t care about.

In that sense I think that more cost effective DACs have more distinguished “personalities” than higher performance DACs.

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@tedsmith

Hi Ted,

Just curious to know which R2R ladder dac u heard and liked ? Is it from MSB ?

Based on my understanding probably MSB is the only company who has invested to build their own r2r chip.

Regards,
Sourav

No it wasn’t an MSB. The one I heard was a few years ago at a show. I’m not even sure I’d recognize the name if someone said it.

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The Denafrips Terminator is an excellent sounding R2R DAC

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It was the Denafrips that I heard :slight_smile:

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I have a new Border Patrol SE-i R2R DAC due to arrive in a week or so, as soon as Gary Dews builds it. It uses a similar old Philips chip as the MHDT line. MHDT has a tube output stage. The Border Patrol uses a tube rectifier to effect the power, something Border Patrol specializes in for their other products. I am very interested to compare it to the DSJ. I chose the BP over Denfrips because of my theoretical attraction to tube topography. And I like the backstory that Gary, the Border Patrol owner/ designer, met an old Japanese tube amp master who taught him that an all copper chassis sounds best, which translates in my mind as an organic Zen component! And each BP dac is handmade by Gary rather than mass produced in China, or a certain Boulder sweatshop :rofl:

The Terminator is in the same price range as the DS Sr.

Just looking at the box full of parts, I thought in the PSA calculation model (parts cost x factor) it would have to be double as expensive…or am I totally wrong and all those caps and a few more normal chips etc. are cheap compared to an FPGA? :wink:

Wait. I own MSB’s best DAC, AFAIK it is not a R2R DAC? If it is color me an idiot.
I agree on DAV.E Mine is also on my headphones! I take my headphones seriously too, MY DS is in my bedroom system loudspeakers. Which is not my reference system. However it is the system I use the most. I honestly really do not see the need for a DAC better than the DS for most people. It to me is an A+ DAC. Look how old it is. It has stood the test of time. Just enjoy what you have.

A friend is lending me a Terminator just to play with. Will it sound better than your DAC ? My personal bias says no but I’m curious. It only has one I2S input and I need two. So that’s a win for the DSSr.

I don’t have a valid opinion: a fellow at a show asked if I would come and listen to a DAC. He was surprised that I didn’t bad mouth the Terminator. But comparing by memory something that was only heard once at a show isn’t fair to anyone.

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