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  1. First , thanks to Audiophilestyle for this great opportunity. I have a few things that I am curious about: - Where does Bruno think class D is heading and where are the improvements going to come from? There are companies which now use gallium nitride transistors and are pushing the switching speed into the MHz region. Does Bruno think this is the way forward? - Class D has achieved very low levels of distortion, but is it possible for class D amplifiers to continue their evolution into something close to a straight wire with gain, i.e. minimal phase shift in the audio band? - Are you using the same feedback scheme which was developed for ncore in the new amplifiers? - Does the high damping factor of class D amplifiers negatively affect the subjective sound quality of some types of speakers as some reviews seem to suggest? Finally some requests: A few things that I did not like in ncore development and I hope will be better with Eigentakt: - It took so long to get ncore amplifiers with a variety of power ratings, particularly for the lower power parts and when they came they seemed to be positioned below the nc400/nc500 and nc1200 . - Did we really need a halo part with, frankly, an eyebrow raising price (I am looking at the nc1200)? - Please no capacitors with low capacitance stability vs frequency in the output filter in the lower end models. The polyester caps used in the nc400/nc500 apparently acted like capacitors with variable tolerance when faced with the variable switching frequency of the amplifier creating additional errors for the feedback scheme to correct. Some users have replaced those caps with metalized polypropylene caps (space on the board did not accommodate normal polyp. caps) and reported noticeable improvement in sound quality. I think the coming 5 to 10 years will be great for class D amplifiers. There are more companies developing and adopting the technology and Bruno was one of the instrumental figures in achieving a well earned acceptance for switching amplifiers in the audiophile word. I am very excited to see what Purifi has to offer for both amplifiers and speaker drivers.
  2. Sagittarius

    HQ Player

    Interesting. I think this simple calculation sheds some light on the reported performance of various processor designs with the more strenuous HQPlayer algorithms. It makes sense not to waste many of those clock cycles over latency, hence the importance of cache size, or other unrelated processes, which is probably part of the reason, beside larger total cache size, that some processors with a large number of cores are reported to perform ok with HQPlayer's more difficult loads despite their lower clock speeds as they have more free cores to use. One question I have is whether the newer non-inclusive victim L3 cache design that Intel have been using with Skylake X processors is still useful for HQPlayer more demanding loads. In other words, would one be (at least theoretically) be better off using a high core Broadwell generation processor with its larger L3 inclusive cache than going with Skylake X?
  3. Sagittarius

    HQ Player

    Hi, I would like to know if Miska or any HQ Player user have experience they can share about running 512x DSD upsampling on Ryzen, or Threadripper CPUs and whether there are any limitations on the upsampling filters that can be used in such a setup. I am considering building a PC around AMD's latest generation CPU's but I am a bit worried because they are behind Intel in terms of AVX implementation, though these CPUs sometimes seem to do quite well in compute tests.
  4. Quick but relevant question for Miska. Do you think if the upcoming E5 Skylake Xeons have AVX 512 instructions or a subset of the AVX512 instruction set enabled as expected, that would allow HQ player to required lower minimum base frequency requirement? My understanding is that AVX 512 should allow doubling the floating point operations executed per clock cycle.
  5. Sagittarius

    HQ Player

    A detailed spec table was published in this recent anandtech article NVIDIA Posts Full GeForce GTX 1070 Specifications: 1920 CUDA Cores Boosting to 1.68GHz Apparently nvidia decided to deliberately cripple FP64 performance in Pascal consumer cards and limit it to 1/32 of the FP32 performance, i.e. the same ratio as Maxwell except that Maxwell did not have much FP64 hardware in its silicon to start with. I have been expecting this to happen and I have a strong feeling that the Quadro variant will be partially disabled as well, except may be for the most expensive ones. FP64 is a specialized need and nvidia will make sure those who need it pay for it. Now this gives the GTX 1080 a theoretical maximum throughput of slightly more than 278 Gflops. To put this into perspective (the unknown effect of graphics RAM speed aside), this is less than half of the theoretical peak FP64 throughput of Intel's latest integrated GPU (Iris Pro P580). I know you said before that Open CL is not suitable. However, I hope you will consider using it at least to partially do what you could do with CUDA.
  6. Just a quick question, does HQ player support acceleration via Intel integrated GPUs?.
  7. I never found it clear how Lampizator does DSD conversion. Their website says "THE LAMPIZATOR DSD DAC HAS USB PORT BUILT IN, SOLID STATE DIGITAL FILTER, PASSIVE DISCRETE ANALOG FILTER AND ACTIVE DISCRETE TUBE FILTER. " Now, the only digital filter I have seen implemented for DSD in my limited knowledge is a "moving average" digital filter with different implementations. I understand it is built in the Burr Brown DAC chip which ifi uses, and is also implemented in Accuphase DACs via a combination of DSP and the multichannels of the ESS DAC chips. (Is this also the filter implemented in the DSC 1 with discrete components?). So for Lampizator I am not sure whether some DAC chip is involved or not in their DSD DACs. It is also not likely a no-dac approach (which I understand as being just simple low pass filtering). All of this is of course of little importance and more a matter of curiosity as apparently their analog implementation is superb and their DACs sounds great.
  8. Yes, they say they have developed their own 1-bit DAC and according to the available photos there are 4 of them inside the DAC8 DSD. It seems they follow a purist approach for their DSD processing inside the DAC. From the user guide: " In the past it has been standard practice to apply digital and analogue filtering processes in an attempt to reduce DSD noise, but such solutions are never entirely without side effects on sound quality. For the DAC 8 DSD we have developed two special techniques designed to eliminate the sonic disadvantages: 1. The True-DSD technique, consisting of a direct digital signal path without filtering and noise-shaping, plus our True 1-bit DSD D/A converter 2. Analogue reconstruction filter with adjustable bandwidth "
  9. You touch upon a point that I have been curious about so I want to seek more clarification as I am not totally on top of what can be accomplished or corrected through DSP. I understand apodizing filters changes the occurrence of the ringing that a steep digital filter introduces from happening before an impulse to happening after an impluse and hence has the potential to sound more natural. But if that is correct, the blurring remains but is less offensive. Can the apodizing filters be tuned somehow to remove the ringing if the filter in the ADC is known? When you say you can not unfilter the ADC, do you mean that any negative effects introduced by the filters in the ADC, including ringing/smear, can not be corrected except for frequency and phase response?
  10. Sagittarius

    HQ Player

    Hello Miska, I am trying to plan a PC upgrade. I hope you can shed more light on how you expect GPU acceleration support in HQ Player to evolve. Do you expect nVidia GPU's only to be supported or is there a plan to also support ATI GPU's and Intel's own GPU's like the ones in Skylake processors? What is the minimum number of single/double precision Gflops in a GPU that would be adequate to run HQ player filters/modulators without limitations, say for converting everything up to 512Fs DSD.
  11. I hope you will making this product : range: micro / model: iUSB pro A USB re-generator that also acts as a USB hub and detects the incoming data stream and directs it based on its content. So, for example, if it is PCM, it goes to DAC#1 and if it is DSD or DSD encapsulated as PCM, it goes to DAC#2. Alternatively, if it is CD quality it goes to DAC#1, if it is high resolution or DSD, it goes to DAC#2. If that is the product, I hope both scenario's are implemented.
  12. Thanks for all who replied. I have a question for Blu. Does WAV sound better than other formats in both Audirvana and Pure Music. The reason I am asking is that Pure Music decompresses files before buffering them in memory and as such should level the playground between uncompressed and lossless-compressed formats. I guess I will buy a license for Pure Music and compare WAV to AIFF and Apple lossless in my setup.
  13. Hello, I have my music collection on a PC in a mix of FLAC, Ape and WAV files. I am new to MAC and I would like to covert the audio files to a MAC-friendly format which will hopefully also be PC-friendly. I use Pure Music on the MAC and J. River player on the PC. I am new to MAC computers and due to the amount of effort and time this procees will take, I would like to cut through the trial and error. - I am considering converting the collection to Apple lossless or AIFF. Are these optimal formats for MAC? - Are there any recommended converters ? My search has led me to Max for MAC and DBpoweramp for PC. The batch mode of DBpoweramp is particularly useful. However, I got to know that Apple has not documented its Apple Lossless format. Max seems to be using CoreAudio for conversion so I wonder if its conversion is more accurate. regards, Hesham
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