Digital Signal Transmission

[kumakuma]

13 minutes ago, fas42 said:

I agree with the thrust of what you're saying. If the DAC is not good enough, then one solution is to buy, a "better DAC". But IME such units are still very, very expensive - a frugal buyer's solution is to add the engineering "on the outside" for more modest cost units; but it may take good understanding what one's after, to do that successfully.

 

A solution that only makes sense IF it is technically possible to make such modifications to the DAC AND you have the required skills and knowledge AND you have no better uses for your time.

[kumakuma]

Dup

[fas42]

1 hour ago, kumakuma said:

 

A solution that only makes sense IF it is technically possible to make such modifications to the DAC AND you have the required skills and knowledge AND you have no better uses for your time.

 

Every half keen audiophile does that already - except, it's called tweaking .. remember, we're talking external stuff. Hmmm, vibration might be a problem, okay, we'll explore mounting it on different platforms; power supplies aren't good enough, okay, we'll add external mains power conditioning to compensate for the lack of internal cleaning up of such; it's sensitive to the nature and quality of input waveforms, okay, we'll condition those in myriads of ways, to address the fact that the internal engineering is not robust enough to cope with whatever comes its way ... and on it goes ...

 

If you're an audio enthusiast, you want better sound ... normally 😜. Therefore, a  good use of your time is to try things to "make it better" ...

[sandyk]

1 hour ago, kumakuma said:

 

A solution that only makes sense IF it is technically possible to make such modifications to the DAC AND you have the required skills and knowledge AND you have no better uses for your time.

 Even then, the front end still matters as Gary has shown here :

https://audiophilestyle.com/forums/topic/60381-hdd-to-case-bonding-uptick-in-sq/?tab=comments#comment-1102477

 

This needn't cost more than a few $ to obtain a very worthwhile improvement

[kumakuma]

36 minutes ago, fas42 said:

 

Every half keen audiophile does that already - except, it's called tweaking .. remember, we're talking external stuff. Hmmm, vibration might be a problem, okay, we'll explore mounting it on different platforms; power supplies aren't good enough, okay, we'll add external mains power conditioning to compensate for the lack of internal cleaning up of such; it's sensitive to the nature and quality of input waveforms, okay, we'll condition those in myriads of ways, to address the fact that the internal engineering is not robust enough to cope with whatever comes its way ... and on it goes ...

 

If you're an audio enthusiast, you want better sound ... normally 😜. Therefore, a  good use of your time is to try things to "make it better" ...

 

Or you just buy better equipment from the get-go and spend your time <gasp> actually listening to music...

[TomJ]

7 hours ago, fas42 said:

 

Every half keen audiophile does that already - except, it's called tweaking .. remember, we're talking external stuff. Hmmm, vibration might be a problem, okay, we'll explore mounting it on different platforms; power supplies aren't good enough, okay, we'll add external mains power conditioning to compensate for the lack of internal cleaning up of such; it's sensitive to the nature and quality of input waveforms, okay, we'll condition those in myriads of ways, to address the fact that the internal engineering is not robust enough to cope with whatever comes its way ... and on it goes ...

 

If you're an audio enthusiast, you want better sound ... normally 😜. Therefore, a  good use of your time is to try things to "make it better" ...

I agree with you regarding the analogue part of the chain. But regarding the digital side the goal must be to transport the data without any influence to the DAC. And cable-sound or sound of a router should not be the target. But I can still here slightly differences of USB cable from Isolator to the DAC. This could be because different cable handle HF and noise different. Best way would be, that the Isolator would be integrated on the board of the DAC.

[fas42]

Just now, TomJ said:

I agree with you regarding the analogue part of the chain. But regarding the digital side the goal must be to transport the data without any influence to the DAC. And cable-sound it sound of a router should not be the target. But I can still here slightly differences of USB cable from Isolator to the DAC. This could be because different cable handle HF and noise different. Best way would be, that the Isolator would be integrated on the board of the DAC.

 

Yes, the isolation mechanism should be part of the DAC - the concept is that the converter is able to handle any digital input which is measurably correct, even though the signal lines, waveforms are as noisy as hell, with zero audible impact. That is just good engineering, and should be the end goal.

[TomJ]

34 minutes ago, fas42 said:

 

Yes, the isolation mechanism should be part of the DAC - the concept is that the converter is able to handle any digital input which is measurably correct, even though the signal lines, waveforms are as noisy as hell, with zero audible impact. That is just good engineering, and should be the end goal.

To transport the true data to the DAC is an IT task. USB asynchronous can do best with lowest jitter rate (if any). So I do not understand, why many so called Audiophiles prefer an unstable SPDIF and setup masterclocks for thousands of euro with the end, that transport of data is only near the quality of USB. I think many people try to use their knowledge from the analogue domain to optimize the digital side - but these are completely different technologies.

[fas42]

12 hours ago, TomJ said:

 I think many people try to use their knowledge from the analogue domain to optimize the digital side - but these are completely different technologies.

 

The purpose of the waveforms are very different - the digital ones serve as the transport mechanism for digital data. But what we are really worried about is the integrity of the resulting, after D/A, analogue waveforms - and, unfortunately, this is highly susceptible to interference, electrical noise. Which the digital waveforms can carry in large quantities, or provoke other parts of the circuitry to effectively generate ... just saying this shouldn't happen doesn't make it so; the designer has to go to the effort of guaranteeing  that it doesn't.

 

Hence, knowledge from the analogue domain can be very, very useful - just putting things into different boxes, with "Analogue", and, "Digital", labels on them doesn't solve a thing - engineering has to get into bed with the players, and make sure that good enough isolation is in fact the case.

[sandyk]

13 hours ago, TomJ said:

So I do not understand, why many so called Audiophiles prefer an unstable SPDIF and setup masterclocks for thousands of euro with the end, that transport of data is only near the quality of USB

 That statement shows a complete lack of knowledge and Anti  Subjective Bias .

Well implemented Coax SPDIF * can crap all over typical USB, even when you are using a USB Isolator.

USB is highly sensitive to the quality of the PSU area and is highly susceptible to minor earth lops and capacitance to mains earth. That is why some members use internal USB cards with a high quality low noise Linear PSU, or a USB Isolator with a separate low noise PSU . Even when using a low noise Linear PSU, simply connecting the screen of a lower noise R-Core transformer to mains earth can cause a small audible degradation. The use of a battery derived PSU, e.g. a 12 Li Ion battery using a low noise voltage regulator results in a further improvement. 

 

*By well implemented Coax SPDIF, I mean using an internal Soundcard which further improves the PSU area and results in a higher quality output than just Motherboard SPDIF, the use of isolation transformers at the PC end AND the input to the DAC, as well as the use of impedance matched plugs and sockets such as genuine 75 ohm BNC types.

 Unfortunately, these days many DACs skimp in this area due to the " Bean Counters" 

 Attached is a photo of an old modified Musical Fidelity X-DAC V3 showing how this was done properly (top of photo) This DAC also used a P.L.L. ( Phase Locked Loop) for the correct timing of the Data .

 The main drawback of Coax SPDIF is bandwidth related, which these days can easily be greatly extended using for example a wide bandwidth (200MHZ) I.C.  at the output instead of something like a typical <$1 Hex inverter I.C.

If you don't need multichannel or DSD, well implemented Coax SPDIF will easily outperform typical USB without the need for USB isolators/Regens, expensive after market USB cables and additional low noise Linear PSUs etc.

 

 See also actual USB measurements :

https://www.computeraudiophile.com/forums/topic/24275-ac-filtering-grounding-boxes-linear-psu-and-balanced-power/?page=68 posts by YashN

[sandyk]

54 minutes ago, fas42 said:

knowledge from the analogue domain can be very, very useful - just putting things into different boxes, with "Analogue", and, "Digital", labels on them doesn't solve a thing

Agreed.

The PSU area also matters just as much for the Digital area as it does for the Analogue area . and correct earthing techniques matter even more for Digital due to UHF and GHZ frequencies being involved.

Even the use of pop rivets in the construction of a PC's metal case can cause some audible degradation,  including reduced stereo separation and a degraded sound stage, as well as a grainy background or what appears to be a veil over the sound. 

[fas42]

Just now, sandyk said:

 Even the use of pop rivets in the construction of a PC's metal case can cause some audible degradation,  including reduced stereo separation and a degraded sound stage, as well as a grainy background or what appears to be a veil over the sound. 

 

That's an interesting one! As compared to using what to bond the parts of the case together? And what is considered to be going on here?

[TomJ]

37 minutes ago, sandyk said:

 That statement shows a complete lack of knowledge and Anti  Subjective Bias .

 

 See also actual USB measurements :

https://www.computeraudiophile.com/forums/topic/24275-ac-filtering-grounding-boxes-linear-psu-and-balanced-power/?page=68 posts by YashN

I was talking about USB as a data transport, not as a power source for a dac, what was the focus of the measurements of your link.

Maybe it is known, that there are DAC not using the power of USB.

Lack of knowledge?

This is what I mean that there is so much confusion around digital audio.

I talked about the data precision of USB in case of feeding a LPS powered DAC  (my RME) and you show me the dirt of USB power and all the people think USB is eval.

[sandyk]

37 minutes ago, TomJ said:

I was talking about USB as a data transport, not as a power source for a dac,

The quality of the USB power matters just as much for DACs that don't need USB to power them.

The noisy +5V SMPS derived USB supply induces rubbish into the D+ and D- data lines of the USB cable , which is why some expensive aftermarket USB cables separately shield both power and Data .

IF you don't need your DAC to see the noisy incoming +5V you can isolate the noisy +5V at the PC end of the USB cable.

In fact, if you don't need it, as a front panel USB port is fed via a couple of  feet long internal USB cable, a further improvement can  often be obtained by cutting the red +5V wire near the Motherboard socket end of the cable.

 

 P..S.

 Even though your DAC may not be powered via USB, it may still need to see a " handshake" via the +5V from the  PC, in which case this noisy +5V can still induce RF/EMI into the Data wires 

[pkane2001]

2 hours ago, sandyk said:

Even the use of pop rivets in the construction of a PC's metal case can cause some audible degradation,  including reduced stereo separation and a degraded sound stage, as well as a grainy background or what appears to be a veil over the sound. 

 

Of course! Got anything objective to back up this bold and exciting claim? I'm ready to weld if you do 🤪

[sandyk]

22 minutes ago, pkane2001 said:

 

Of course! Got anything objective to back up this bold and exciting claim? I'm ready to weld if you do 🤪

This came as a result from Gary's suggestion.

 https://audiophilestyle.com/forums/topic/60381-hdd-to-case-bonding-uptick-in-sq/?tab=comments#comment-1102477

 

 Of course, if you don't believe that markedly reducing the measured A.C voltage drop between the 0 volts of the case of an internal SSD and 0 volts (Earth) of the internal PSU matters . . . . . .

 

 

https://www.google.com/search?q=replace+the+pop+rivets+in+a+PC+case&oq=replace+the+pop+rivets+in+a+PC+case&aqs=chrome..69i57.24374j0j15&sourceid=chrome&ie=UTF-8

[pkane2001]

1 minute ago, sandyk said:

This came as a result from Gary's suggestion.

 https://audiophilestyle.com/forums/topic/60381-hdd-to-case-bonding-uptick-in-sq/?tab=comments#comment-1102477

 

 Of course, if you don't believe that markedly reducing the measured A.C voltage drop between the 0 volts of the case of an internal SSD and 0 volts (Earth) of the internal PSU matters . . . . . .

 

So you’re talking about improving a ground connection, and not just about rivets sounding better? Ok, I’ll put my welder away, then ;)

[fas42]

20 minutes ago, pkane2001 said:

 

Of course! Got anything objective to back up this bold and exciting claim? I'm ready to weld if you do 🤪

 

My feeling is that the panels of the case, if metal, are not well electrically connected - if relying on pop rivets to do this, it most likely will fail; from paint, etc. If self tapping screws, which properly bit into the metal, were used, I suspect the variance would go away.

[pkane2001]

1 minute ago, fas42 said:

 

My feeling is that the panels of the case, if metal, are not well electrically connected - if relying on pop rivets to do this, it most likely will fail; from paint, etc. If self tapping screws, which properly bit into the metal, were used, I suspect the variance would go away.

That I can believe. I’ve seen a number of cases with poor ground connection with screws on top of a painted or an anodized surface that are likely not to make good contact.

[sandyk]

19 minutes ago, pkane2001 said:

So you’re talking about improving a ground connection, and not just about rivets sounding better? Ok, I’ll put my welder away, then ;)

 Not that your DeltaWave S/W will be likely to show the obvious audible improvements though, because your beloved checksums remained the same after the same CDs were re-ripped  !😊

OR 

 Put another way, the Binary Data remained the same.

[pkane2001]

3 minutes ago, sandyk said:

 Not that your DeltaWave S/W will be likely to show the obvious audible improvement though, because your beloved checksums remained the same after the same CDs were re-ripped  !😊

Sorry, Alex, checksums are your hobby. Never bothered with them.

[PeterSt]

6 hours ago, TomJ said:

I was talking about USB as a data transport, not as a power source for a dac, what was the focus of the measurements of your link.

Maybe it is known, that there are DAC not using the power of USB.

Lack of knowledge?

 

Tom, already yesterday I typed a post that you show more and more that you don't understand a think of this all. This time I won't scratch my text.

You really have no clue.*

 

*) This happens to more of us, so no big deal. But don't twist this into the others not understanding.

 

You appear to have so few knowledge about this, that you don't understand a word of what the others are telling.

 

PS: Nobody talked about the power over USB, nor implied it, nor even thought about that. Only you do. With this little fact in mind, go read all again and try to see what the subjects really are. OK ?

PPS: Alex did, but only in response to your pose. And it is not even relevant.

 

 

[PeterSt]

And @TomJ, now we are as far as knowing that you need to learn about "everything" in this realm, what interferences (you speak abut all the time) do you have in mind ? I feel that if we work this out, you will suddenly be a lot more knowledgeable. 

Heads up.

[PeterSt]

6 hours ago, sandyk said:

 P..S.

 Even though your DAC may not be powered via USB, it may still need to see a " handshake" via the +5V from the  PC, in which case this noisy +5V can still induce RF/EMI into the Data wires

 

Alex, I think you may be confusing the handshake procedure with ground being required. Maybe in some occasions +5V is needed (I don't know about them - but that doesn't tell much 🤪) but ground most often (always ?) is required. And this ground is not required for the data ...

[PeterSt]

6 hours ago, sandyk said:

The quality of the USB power matters just as much for DACs that don't need USB to power them.

 

... additionally ... each DAC which requires 5V over USB to power itself, can be regarded a toy. So IMHO such DACs should not be the subject of this topic. It could confuse the OP (haha).