[Sunya]

Hi-Fi News

 

[bigfatpaulie]

  Weird? I'm using the Hugo TT and have zero issues with Tidal, Amarra, or Audirvana with DSD through my iMac. 

 
Now, thanks to JaZZ, it is working perfectly.  I don't have any DSD256 but DSD128/64 works perfectly.  I think it may been symptomatic of Foobar being free it is less polished.
 
 
(Or it could be me.  It's probably just me...)

 

[Rob Watts]

No it's not you, I had a nightmare with it, it took forever to set up. Lots of wasted hours, only to discover that DSD512 still sounds poorer than redbook on Dave.
 
Rob

 

[Rob Watts]

  Exactly, why would anyone want to add dither to an unchanged file? No more bit perfect playback? The purpose of dither (noise) is to randomize the quantization errors resulted from the truncation of a 24 bit file to 16 bit one. A 16 bit file already has dither in it. 
 
A good dither material:
 
http://downloads.izotope.com/guides/izotope-dithering-with-ozone.pdf

There are a number of reasons why adding dither can be beneficial for a DAC. In practice we are talking about converting 16 bit data to 32 bit data by adding rectangular PDF noise onto the blank (all zeroes) data - its not really dither as such, because we are not talking about treating truncation errors as there is nothing to truncate as its all zero. And the top 16 bits would still be bit-perfect, as one would only randomise the zeroes.
 
The first reason is small signal non-linearity. By randomising small signals, you improve the performance of the DAC - but this tends to work best when you have a number of DAC's in parallel and feeding each DAC with random noise. By averaging the output, it means you can use much more noise. This used to work well in the past, but stopped making any difference when I invented pulse array, as this DAC technology has no small signal non-linearity. By using noise (I won't call it dither) like this made the SQ smoother and with better depth - all hallmarks of better small signal performance.
 
The second issue is DSP core PSU noise being signal correlated, which then gets picked up by the analogue electronics, and this mechanism also degrades small signal non-linearity, so upsetting depth reproduction. This issue used to be a major thorn in my side, as the DSP cores I had to manually create from FPGA fabric, and they consumed a lot of power, so there would be lots of noise entering the ground plane. This issue has slowly been eliminated, and since Hugo I have had zero measurable problems from it; this is due to a number of reasons:
 
1. Dedicated DSP cores on the FPGA, which are extremely power efficient.
2. Dual ground planes making ground bounce no longer an issue.
3. Use of switch mode PSU, with the current return path located under the FPGA, thus meaning no signal correlated currents leaking away from the FPGA section.
4. Nearly a quarter of a second of music data being processed through the WTA, so current draw is less signal correlated.
 
Now randomising the bottom 16 bits will randomise the DSP currents, and this can reduce this problem as the WTA is busy processing random data, so the signal correlated part gets smaller.
 
Now in the past I could not hear any benefits in randomising the permanently zero bits, and so dropped the feature. But we are in uncharted territory with Dave, as it offers depth reproduction to a level that I have never experienced before - for the past 20 years I thought 200 dB pulse array noise shapers were good enough for depth - but now with Dave at 350 dB I need to re-examine this issue, as it may now offer some benefit.
 
Rob

 

[Jawed]

hey,do anybody remember what is that magazine called where Dave was reviewed & measured? i saw it about two months ago but since then I forgot how was it called so I cant find it

PDF of review:

http://hifilounge.co.uk/image/attachments/Chord/HFN-Chord-DAVE.pdf

 

[bigfatpaulie]

  No it's not you, I had a nightmare with it, it took forever to set up. Lots of wasted hours, only to discover that DSD512 still sounds poorer than redbook on Dave.
 
Rob

 
HAHA!  I hear that!!
 
DSD is neat I suppose.  It seems to good for very complex passages and preserving some mircodetail (I guess...) but I certainly don't look down or feel at all shorted by RedBook after spending some time listening to DSD128 files.  I find it to be simply just not as enjoyable to listen too (at least for now).

 

[TheAttorney]

Last year I played about with HQ Player's myriad DSP options - this from a Windows laptop to the iFi iDSD.
 
With that combination, HQP's Dither and Filter and PCM upsampling and PCM->DSD conversion options really made a positive impact to redbook FLAC files. And even with all DSP options switched off, HQP still sounded better than JRiver (shame about the clunky interface though).
 
Now with DAVE in the picture, I took a break from my Nagra CDC as source and hooked up my i7 Windows 10 SSD laptop, running on battery,  via USB cable direct to DAVE and tried a few options, with the following observations:
 
HQP still sounds better than JRiver (both with all DSP options off and both with DAVE's driver), but the difference didn't seem as obvious as I remembered with the iDSD. From then on all listening was with HQP.     
 
Following romaz's comments, I didn't bother with any up-sampling or up-conversion options for DAVE. Just added the TPDF Dither and additionally tried Miska's best Filter options poly-sync and poly-sync-mp (which had significantly improved the iDSD setup). The Dither did seem to give a slight SQ uplift, and the Filters gave an interesting alternative - I couldn't decide if it was better or worse. @romaz did you try these particular filter options? They do load the processor more, but the load was insignificant on my i7.
 
I wouldn't consider any of this to be conclusive and I haven't ruled out imagination at this point. More food for further investigation, but what I did notice was that this was the first time I had heard a computer sounding better than my Nagra CD Player (TBH, I haven't tried very hard so far with computers in my main rig). And based on recent comments on the microRendu, it sounds like there's room for further improvement.

 

[goobicii]

does DAVE support 705600 hz  samplerate? 

 

[ecwl]

I can only comment on JRiver TPDF dithering. My Windows PC is set to use the Kernel Streaming driver with output to 32-bit. So in JRiver, TPDF dithering would be applied at 32-bit, even if my source is 16-bit/44kHz and then output will be 32-bit/44kHz.
 
What I don't know with HQPlayer is that if a file is 16-bit/44kHz and you turn on TPDF dithering, does it apply the TPDF at 16-bit or does it apply at the output bitrate, e.g. 24-bit or 32-bit. I am guessing that if it applies it at 24-bit or 32-bit, then as Rob Watts said, it may help with small signal non-linearity? But if HQPlayer is applying TPDF at 16-bit, then what may be happening is that some recordings may not be properly dithered or have an inferior dithering algorithms so by applying TPDF dithering over them, you're improving the dithering of the original recording? Not sure...

 

[Rob Watts]

Yes - I know it works as you can cascade two Dave's together with the DX OP feeding the dual BNC input on another Dave.
 
Rob

 

[Sonic77]

Downloaded HQ Player, and it is so awesome! Thank you to Miska !!

 

[TheAttorney]

Hi Sonic77, are you including the mR between computer and DAVE?

 

[Kakki]

Dear Dave owners, do you have any recommendation or opinion on which color (silver or black) one should choose?
I would appreciate to hear what made you choose the color and what do you feel about your choice after spending your time with Dave...
It is such a difficult decision to make!

 

[bigfatpaulie]

The black one sounds better with Redbook files but the silver one offers DSD1024 so...  

 
I went with black simply because I couldn't see the unit before I bought it and I was concerned that it may look cheap in silver.  Having now seen the unit, and the build quality (which is fantastic) it would just come down to which I thought was nicer with the rest of my system.  If I was doing it again, I would get a silver one (because it is so nicely made). 

 

[JaZZ]

  The black one sounds better with Redbook files but the silver one offers DSD1024 so...  

 
...I'm glad I decided for black. Although I must say that the silver DAVE looks good as well. But then again, I don't listen to DSD, just for testing purposes.