May not be that straightforward....
My understanding is that R2R ladder DACs are multi-bit, requiring parallel feed of bits to all the "rungs" of the ladders. Perfectly matched for PCM data but 1-bit DSD would first require conversion to parallel format and this has to be done on the fly. So extra processing load for the FPGA and takes a performance hit accordingly.
On this point a sigma-delta DAC like ESS 9018 will feel at home with 1-bit DSD as the DAC engine processes likewise. But accordingly less than perfect with PCM that needs to be bit streamed first before feeding into the DAC cells.
DAC manufacturers will not usually say so but I reckon if you are using R2R DACs stick with PCM and if Sigma-Delta go for DSD material. Horses for courses as they say
May not be that straightforward....
My understanding is that R2R ladder DACs are multi-bit, requiring parallel feed of bits to all the "rungs" of the ladders. Perfectly matched for PCM data but 1-bit DSD would first require conversion to parallel format and this has to be done on the fly. So extra processing load for the FPGA and takes a performance hit accordingly.
On this point a sigma-delta DAC like ESS 9018 will feel at home with 1-bit DSD as the DAC engine processes likewise. But accordingly less than perfect with PCM that needs to be bit streamed first before feeding into the DAC cells.
DAC manufacturers will not usually say so but I reckon if you are using R2R DACs stick with PCM and if Sigma-Delta go for DSD material. Horses for courses as they say
Hi Acko
Thanks for your feedback.
Let me explain in more details.
If we can get the 2.844Mhz 1bit DSD signal to the DAM DAC.
Since the FPGA can already out put 2.844Mhz.
Then we can just turn the R2R DAC PCM all bits high for DSD signal 1,
Then turn the R2R DAC PCM all bits low for DSD signal 0.
In essense, I just treat DAM R2R 28bit DAC as one single bit DAC.
The DAC still functions in PCM mode, however, with 2.844Hmz 28bit PCM signal
Just the PCM signal only has two value, equavlalent to a single bit DAC. And this is essencial pure DSD.
I would expect this to be very low calculation load for the FPGA. And the whole process does not manupulate DSD signal at all. No Digital Filter whatsoever.
In addition, as R2R PCM ladder out put depends on the PCM signal value, we can set the PCM value to tune volume.
one example,
Let's say the DSD signal is 0,1,0,1,1,0
Then the corresponding 28bit PCM vlaue is 0,2^28, 0,2^28,2^28,0
If we want to tune the volume down a little bit, then we can set the PCM signal to be: 0, 2^20,0,2^20,2^20,0
If this is possible, then this DAM dac can be a pure R2R DAC and a Pure DSD DAC
What do you think?
Thank you
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Yes, I can follow your logic, very nice concept indeed! Let us see what Soren has to advise on this
Thank you
hope this can become a open source firmware program that may have more interesting thing to play with? An open source dacSent from my iPhone using Tapatalk
I have been listening this DAC several days in a very casual set up. To me the best description about this DAC is that on the day I received it, I plopped it into my enclosure with Amanero, run few short wires, took raw SE output straight into amp and voila. Power supply is my Tektronix lab power supply (DC obviously) Irony is that I have been listening it while I am working on my mega multichannel DAC crossover, that I have been involved who knows how long, consisted of 11 transformers, 30 various power supplies and super regulators, not counting ones on the particular boards...
No I/V converter needed, no buffers needed, nothing... just straight to the amp. Pure beauty. As for the sound, I really like it. Last night was the first time I really decided to do nothing but to listen. On a good recordings it sounded really nice. In my set up, what was notable was absence of any harshness. Really warm and well balanced. On really good recordings I could not stop tapping and enjoying. Great space and exceptional detail, again without any harshness. Now given, my lab is relatively small and speakers are sort of made for monitoring - PHL mid bass + RAAL smaller ribbons. Supported bellow 60 Hz with Velodyne sub. So honestly I would not elaborate on spacing much, it will need to be listened on my bigger set up in a living room. But for tonality this set up is really good for judgements. With less than desirable recording it did sound sort of flat, but what DAC will sound good with average recordings?
In summary, its simplicity and easiness to put it together is a great plus. It is all there installed on really well designed and manufactured board. From modding perspective, that is also its biggest disadvantage, as I believe it will be very hard to do much on that board - change clock or power supply if one desires to do so. Price for 0.2% board is very affordable plus given that is very little needed, one could have really great DAC for very low price. In another word there is little wrong about this DAC.
I will be very excited to follow further upgrades as I am sure there is much to come out of this group of talented users. Once I am ready, I will do full set up and complete install including S/PDIF. Than I will do measurements and listening tests with my much loved AckoDAC ESS9012. I have to say, I am very relaxed about it. I know it will sound different, just like different amps or different speakers differ from each other. So far I am very happy with it. Yet, there is a need for DAC for work office, for home lab, for living room, present to my daughter, present to my son... hahaha. It is like with girlfriends. We do not compare them, we enjoy in each one of them while we are with them.
No I/V converter needed, no buffers needed, nothing... just straight to the amp. Pure beauty. As for the sound, I really like it. Last night was the first time I really decided to do nothing but to listen. On a good recordings it sounded really nice. In my set up, what was notable was absence of any harshness. Really warm and well balanced. On really good recordings I could not stop tapping and enjoying. Great space and exceptional detail, again without any harshness. Now given, my lab is relatively small and speakers are sort of made for monitoring - PHL mid bass + RAAL smaller ribbons. Supported bellow 60 Hz with Velodyne sub. So honestly I would not elaborate on spacing much, it will need to be listened on my bigger set up in a living room. But for tonality this set up is really good for judgements. With less than desirable recording it did sound sort of flat, but what DAC will sound good with average recordings?
In summary, its simplicity and easiness to put it together is a great plus. It is all there installed on really well designed and manufactured board. From modding perspective, that is also its biggest disadvantage, as I believe it will be very hard to do much on that board - change clock or power supply if one desires to do so. Price for 0.2% board is very affordable plus given that is very little needed, one could have really great DAC for very low price. In another word there is little wrong about this DAC.
I will be very excited to follow further upgrades as I am sure there is much to come out of this group of talented users. Once I am ready, I will do full set up and complete install including S/PDIF. Than I will do measurements and listening tests with my much loved AckoDAC ESS9012. I have to say, I am very relaxed about it. I know it will sound different, just like different amps or different speakers differ from each other. So far I am very happy with it. Yet, there is a need for DAC for work office, for home lab, for living room, present to my daughter, present to my son... hahaha. It is like with girlfriends. We do not compare them, we enjoy in each one of them while we are with them.
Ooooh, I never said I ever owned a totalDAC. If I did indeed own one, I would be sitting like a stoic on cloud 9 enjoying my music collection. And I would never have danced at this party here at diyaudio
It was however, my experience with this mighty master of dacs that convinced me that a discrete r2r-ladder design was the only type of dac that would truly satify me sonically.
The totalDAC belongs to an acquaintant of mine whose source is a standard laptop playing streamed music from Spotify. Yes, quite lowtech. Nevertheless it works.
I also used my iPad 2 as source using the free app OPlayer Lite.
Later on I bought the Discreet Monica designed by Yeo in Malaysia and it certainly was in the same leauge as the totalDAC in terms of sound signature - especially when being fed by the I2S out of the Amanero. But alas, being a unipolar design it produced distortion with low level signals like a fading piano note and silent passages. So I had to return it after three months of intense use. Enough to give me a solid impression of the sonically trademarks of an r2r-ladder dac.
I am powering the ISO 3.3V directly from the Amanero which is USB powered by the SBT. For the SBT I have an overkill SBooster psu from Best of Two Worlds Solution.
But now I’m already looking to try the D-reflektor.
a lot of info here --> http://www.diyaudio.com/forums/vend...-magnitude-24-bit-384-khz-91.html#post4197094
The one with the 0.02 resistors.Which version? It would be helpful if everyone giving subjective impressions mentioned which version they are using
By the way, my testing setup is a RME UFX as the computer interface, my AD is a PCM 4222 Evaluationboard with a transformer (a HQ Pikatron 4:1) frontend, bypassing the electronics on the board. This AD sounds closer to the source than the UFX AD, that is for sure.
My Monitoring DA is right now a Gustard X-10, not the top of the crop of the es 9018 converters but again, better than the UFX, and I can hear very well the differences from the three files I compared, The original file, the UFX into PCM 422 file and the r2r into PCM file.
next time I am in the studio I will bounce snippets and post them here, so everybody can compare themselves.
I am more of a working studio guy and nobody I know uses r2r dacs in studios, maybe because distortion measurements look kind of scary
And I am still convinced, that converter differences are really small these days, compared to differences, instruments, recording techniques, rooms, microphones and mic preamps make. A lot of classical guys use the RME UFX as their converter and produce great sounding recordings, that then get evaluated on much better DAs, kind of funny.
Tobias
According to datasheets it should be less than total 10 mA at 3.3V for all three parts. Btw, the isolators can actually run on 2.5V-5V....
That would be a single speed DSD DAC with a 250-million step, high pecission, volume control that can be changed at mu-second level.Hi Acko
Thanks for your feedback.
Let me explain in more details.
If we can get the 2.844Mhz 1bit DSD signal to the DAM DAC.
Since the FPGA can already out put 2.844Mhz.
Then we can just turn the R2R DAC PCM all bits high for DSD signal 1,
Then turn the R2R DAC PCM all bits low for DSD signal 0.
In essense, I just treat DAM R2R 28bit DAC as one single bit DAC.
The DAC still functions in PCM mode, however, with 2.844Hmz 28bit PCM signal
Just the PCM signal only has two value, equavlalent to a single bit DAC. And this is essencial pure DSD.
I would expect this to be very low calculation load for the FPGA. And the whole process does not manupulate DSD signal at all. No Digital Filter whatsoever.
In addition, as R2R PCM ladder out put depends on the PCM signal value, we can set the PCM value to tune volume.
one example,
Let's say the DSD signal is 0,1,0,1,1,0
Then the corresponding 28bit PCM vlaue is 0,2^28, 0,2^28,2^28,0
If we want to tune the volume down a little bit, then we can set the PCM signal to be: 0, 2^20,0,2^20,2^20,0
If this is possible, then this DAM dac can be a pure R2R DAC and a Pure DSD DAC
What do you think?
Thank you
You see how flexible the DAM is
speakers vs. headphones
I have only had a brief listening test with my speaker setup which consists of a Unison Research class A tube amp and a pair of Sonus Faber floorstanders. Enough to underline the impression I got from my two very different headphone rigs. Quite digital sounding and not so much analog.
(Sadly I’m not using my speaker rig so much, as I get complaints from the rest of the family).
Headphones are IMO great for testing hifi. With headphones important parameters and great sources for trouble with speakers are eliminated from the equation. Delicate issues such as room acoustics and speaker placement. Of course at the expense of for instance, bass oomph. But as long as I’m used to the sound of my headphones, they will suffice.
And with my budget I can afford top notch headfi gear. It would cost me 10-15 times as much to get the equivalent speaker gear. My Senns are arguably regarded as one of the best cans ever produced.
Note also, that Søren himself on a couple of occasions has mentioned HD650 as his testing gear. I wish more people would do the same. Can be quite revealing and terrifying at times
I have only had a brief listening test with my speaker setup which consists of a Unison Research class A tube amp and a pair of Sonus Faber floorstanders. Enough to underline the impression I got from my two very different headphone rigs. Quite digital sounding and not so much analog.
(Sadly I’m not using my speaker rig so much, as I get complaints from the rest of the family).
Headphones are IMO great for testing hifi. With headphones important parameters and great sources for trouble with speakers are eliminated from the equation. Delicate issues such as room acoustics and speaker placement. Of course at the expense of for instance, bass oomph. But as long as I’m used to the sound of my headphones, they will suffice.
And with my budget I can afford top notch headfi gear. It would cost me 10-15 times as much to get the equivalent speaker gear. My Senns are arguably regarded as one of the best cans ever produced.
Note also, that Søren himself on a couple of occasions has mentioned HD650 as his testing gear. I wish more people would do the same. Can be quite revealing and terrifying at times
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