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Violectric DAC V850 - General Discussion and Impressions Thread

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  1. Ultrainferno
    I created this topic to discuss the brand new Violectric DAC V850

  2. Ultrainferno
    I liked the original V800, I look forward to listening to the V850 in combination with my V281. Edit: Review is online
  3. mulder01

  4. project86 Contributor
    Fried, can you clarity the total number of PCM1795 chips on board? I'm thinking two of them total, which is how the "dual mono" term is usually applied. But it gets confusing to think of "two converters per channel". Because that could mean two separate PCM1795's per channel (for a total of four DAC chips on board) or it could mean one PCM1795 chip per channel, each being a stereo chip. It's confusing even to phrase the question!
    I find this often when using the 8-channel ESS DACs. The press release will mention 8 DACs on board, or quad DACs per channel, which is true... but not quite the same as having 8 ES9018 chips total. 
    Not that this really makes a huge difference either way. 
    galacticsoap likes this.
  5. rx79ez08
    From the spec, I assume no DSD capability?
  6. Ultrainferno
    That's correct. No native DSD
  7. Zkadoush
    It may not be revolution, but on the evolution side it is a significant improvement over the V800. Very interesting and welcome indeed!

    Sorry for not having thought of opening a new thread to ask the questions in the right space. I'll just reiterate my last question from the V281 thread, as the first ones were answered:

    "You have mentioned before in the V281 thread that both you and John Siau - from Benchmark - prioritize THD and linearity over SNR. I believe this is an important aspect to understand, could you perhaps elaborate a bit more on that topic?"

    I'll add the following question:

    "The Benchmark DAC2 series includes an interesting feature, which is the 3,5 dB high-headroom DSP. Is this a significant feature that would be worth implementing in the V850?

    Congrats on the release of the V850, will be getting in line for my own unit.

  8. mulder01
    If it's not a significant improvement, at least the last few v800s should go for pretty cheap :p
  9. fdg
    @ Ultrainferno - thank you

    @ project86
    We have 1 PCM1795 per channel. This DAC includes 2 converters, normally used for left and right.
    We take them for one channel.

    @ rx79ez08  
    I admit: I hate DSD
    DSD came up in the middle of the 90ties in the professional world.
    Why ? I guess because there had to be something new ...
    There is definetely no practical reason to go for DSD and therefore this format is dead since a long time in the recording industry.

    The biggest disadvantage of DSD (there are many more) is: it can´t be edited.
    So, if there is a real DSD recording it is converted to PCM before it enters the mixing console or the editing suite.
    After the necessary steps are made it is back converted into DSD.
    Does this really make sense ??
    And to make a DSD file out of a PCM file is as senseful as upsampling a CD because of the sound ...
    Well, the above is my personal opinion but there is also a practical one:
    We have learned that a DSD data stream can´t be modified and so it is not possible to attenuate such signals in the digital domain.
    As we have implemented the volume control on the digital side there is no way to process DSD data :wink:

    @ Zkadoush
    Yes, low THD and linearity are the specs we are hunting for. SNR is only the vehicle to get there.
    Why that?
    It is not possible to have 100 dB THD (0,001%) with 90 dB SNR, but it is possible to have 110 dB THD (0,0003%) with 120 dB SNR.

    High SNR values are relatively easy to achieve as they only describe the difference between fully off and fully on.
    Some manufacturers of D/A chips include the mute state in their data to rise SNR.
    The SNR of the D/A chip itself is always higher than the SNR measured at the outputs of a specific device because unlinearities and noise will be added from the analog circuitry.
    There had been a time when a German manufacturer constructed a 28 bit D/A converter with a sensational high SNR of over 150 dB.
    This was accomplished with two stagged 18 bit converters and a switching point at -60 dB.
    As only 18 bit converters had been involved with relatively poor THD figures it took a while until people realized that highest SNR is no garantee for a good sound.

    Good sound is achieved by low THD - it describes how exact a sound can be depicted.

    24 bit digital data means a maximum SNR of 144 dB what is far more than nature can offer.
    So theoretically it could be possible to have a THD as low as 140 dB.
    The real world THD from a good A/D converter is a low as -110 dB and it will take lots of efforts to lower it to -115 dB one day.
    More is not possible for my opinion.
    Please always keep in mind that dB describes a logarithm ratio.
    So the difference between 80 and 100 dB is not "just 20 more" but describes a ration of 1:10.000 (80 dB) and 1:100.000 (100 dB) which is a significant difference.    
    A really good D/A converter (like V800) offers -112 dB THD.
    As there is also noise generated from the analog output circuitry there is also THD+N(oise) which is always lower compared to THD.
    In case of V800 THD+N is -108 dB.

    Concerning the "3.5 dB high headroom DSP" from Benchmark I can´t tell you something about.
    Also there is no explanation to find on the web.
    For me 0 dBFs is the maximum you can achieve as there are no positive dB values with digital data.
    So the question is what this headroom is good for. Maybe John Siau will explain some day.
    Thank you,
  10. rx79ez08

    I guess that is a matter of personal opinion. I have enough DSD in my music collection that it would be nice to be able to play them natively. At the very least I found that DSD records to be generally mastered in a better quality.
    On a related matter, now that the USB issue have been sorted, are there going to be a program to exchange the DAC of people who have brought the old 192kHz USB DAC card? I got one of those that i purchased with my V281 when it first came out. I can never get the DAC to work properly with my setup. I just though it is my own problem until I read into it. Now that the chip won't even work with a newer OS, it is rather disappointing for a card that is less than a year old.
  11. mulder01
    Wow, never knew that.  So I guess that means the only reason it sounds better is because they took time time to record it better and has nothing to do with the format...
  12. Zkadoush

    Hi Fried,

    Thanks a lot for your detailed response regarding the relation between TDH and SNR, highly appreciated! It makes good and very important points.

    I also appreciate your frank comments regarding DSD. The inherent flaws of DSD have been widely documented, but for obvious reasons, like marketing, hype and money, DSD has managed to stay in the game, and now ther's even this website to buy native DSD recordings, lol: https://www.nativedsd.com/
    For anyone interested in the topic I'd recommend this little reading (and a few other ones that can be found at Mark Waldrep's REAL HD-Audio Blog) :


    Regarding a little history about how DSD came to be, here's Mark Waldrep's take on it in 3 parts:


    Regarding the "3.5 dB high headroom DSP" Implemented in Benchmarks DAC2 series, the product page of the DAC2 states the following:

    "All D/A converters need 3.5 dB "excess" digital headroom, but few have any headroom above 0 dBFS.

    All of the digital processing in the DAC2 DX is designed to handle signals as high as +3.5 dBFS. Most digital systems clip signals that exceed 0 dBFS. The 0 dBFS limitation seems reasonable, as 0 dBFS is the highest sinusoidal signal level that can be represented in a digital system. However, a detailed investigation of the mathematics of PCM digital systems will reveal that inter-sample peaks may reach levels slightly higher than +3 dBFS while individual samples never exceed 0 dBFS. These inter-sample overs are common in commercial releases, and are of no consequence in a PCM system until they reach an interpolation process. But, for a variety of reasons, virtually all audio D/A converters use an interpolation process. The interpolation process is absolutely necessary to achieve 24-bit state-of-the art conversion performance. Unfortunately, inter-sample overs cause clipping in most interpolators. This clipping produces distortion products that are non-harmonic and non-musical . We believe these broadband distortion products often add a harshness or false high-frequency sparkle to digital reproduction. The DAC2 DX avoids these problems by maintaining at least 3.5 dB of headroom in the entire conversion system.

    We believe this added headroom is a groundbreaking improvement delivering significant sonic advantages."

    More detailed explanations and graphs behind the reasons to implement the 3.5 dB high headroom DSP can be found in two application notes at the Benchmark website, written by John Siau:


    Any thoughts?

    Thanks again for your answers, very much looking forward to the release of the V850 DAC.

  13. hmouse
    Is it possible to bypass the volume control?
  14. gogogasgas
    Q: Is it possible to bypass the volume control?
    A: Putting the volume control to full (OK, my answer is a guess. But, it's what you should do on a Mac when using it's TOSLINK output connected to a DAC, perhaps it's the same for the digital volume of the V850)
  15. gogogasgas
    Reading the last few posts on the V800 thread, Fried said:
    "Out of a sudden by the end of 2014 they discontinued the production of the chips and the software support …  
    We, as well as many others, had been left outside standing in the rain."
    So, does this mean that V850 will REPLACE the V800 in the lineup, or is there another upgrade for the V800 (version 3?) coming out that will rectify the above issues?
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