Debate of DAC design regarding DSD vs PCM among 5 VIPs

[Nikhil]

Louis,

 

Thank you very much for sharing this discussion.  

 

Quote

Interview with Robert Watts from Chord
 5.3 What's so special about your Pulse Arrays DAC? Is it similar to Delta sigma modulation?

 

Would you please translate this section for me.  Thanks!

 

Regards.

[Nikhil]

7 hours ago, louisxiawei said:

 

5.7 The word "tap" is mentioned quite often by Chord when talking about D-A conversion, what on earth is tap?

 

 

Thanks for adding this.  I have also wondered what the term "taps" meant.
I don't think I still understand it but it's a starting point. Need to read up on this some more.

 

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In general, the longer tap length will lead to the result like: digital filter will be more precised, time error of each digital sampling will be smaller. From the point of music playback, the start and the end time of each sound will be more accurate. In theory, the time error from listening experience will be totally eliminated only if the tap has the length of 1,000,000, which cannot be be done according to current technology. The tap of normal digital signal has the length of 100, the top-class device is only 256 maximum, which is far away from the ideal tap length (1,000,000).

 

 

I'm not sure if this is a translation issue but I think that the correct word in English would be "number" instead of "length".  Chord always talks about the number of taps increasing the accuracy etc.  audio.bill's post also refers to number of (FIR) taps etc.  Can someone confirm this?

 

Regards.  

 

[Nikhil]

8 hours ago, Ralf11 said:

The Chord guy has really trashed DSD.

 

Then there is that listening study in JAES from 2007.

 

 

 

The problem I have is that whatever people say negatively about DSD, it doesn't bear with what I hear in my setup.  

If you take the trouble to make the investment in the computing power needed to process DSD (and a DSD DAC), it is a very enjoyable sound.

 

 

[Nikhil]

6 hours ago, Ralf11 said:

 

How much computing power is needed to process DSD ?

 

This depends on the software strategy you want to use for playback i.e. pure DSD vs PCM to DSD conversion. 

Also depends on where you want to do the heavy lifting - on the server or on the DAC chip.

 

On Windows, JRiver or JPlay don't really need a lot of computing power for playback. 

Folks in this camp tend towards the minimal computing strategy and can run into problems running higher DSD rates. 

 

On the other hand HQPlayer and Bughead need huge number crunching ability.  .

Here you have folks adding on nvidia graphic cards (CUDA offload feature in HQP)  to machines with Core i7 processors to process DSD256/DSD512 rates.  The highest computing power is needed for direct DSD to DSD conversion i.e. DSD 128 to DSD256/512 and will stress out most machines without CUDA offload.  

 

About two or three years ago we had a discussion on this using the JRiver Benchmark Test (JRMark)

For running DSD64 the JRMark was around the 3000 mark on i3 processors

For DSD 128 it was around 4000 - 4500 mark so Core i5 processors and above.

For DSD 256 and higher a Core i7 processor would handle the number crunching. .
 

Most new machines with new motherboards and processors will not have a problem up to DSD128.

 

 

 

 

[Nikhil]

On 4/25/2017 at 0:44 PM, Superdad said:

 

I went to my (digital) doctor: I told him I had the jitters.  He said take two flip-flops and call me when the track is over.  

 

 

LOL!  Good one ... 

 

 

On 4/25/2017 at 1:43 PM, Miska said:

Not that I would talk about "good" or "bad" jitter, but he is probably talking about correlated jitter vs non-correlated jitter. So in this case to the similar effect as spread spectrum clocking

 

 Thanks for clarifying that.