Optical vs USB

[AudioPhewl]

You have a PII/700mhz from 1994? Liar! PII didn't come out until several years later, and never touched 700mhz...

PIII flipchips did 700mhz, however. But they weren't out until... erm, '99? Certainly 2000, but can't remember when they were released...

Back on topic - optical is magic for data transmission, same applies to USB. Jitter on USB is a non-starter. USB will take some additional processor cycles, but this will be totally miniscule on a semi-modern PC. I'm using a Celeron D, and have lost no ground on climateprediction, which runs in the background the whole time.

ETA - running Kubuntu here, USB audio is totally problem free.

~Phewl.

 

[chris_ah1]

It's win2000 pentium M solo 1Ghz ULV chip hence the crackle when loaded.

But either way windows USB audio is extremely patchy - too much interferes with it.

 

[AudioPhewl]

Pentium M is still a tidy CPU IMO(I was running an XP1700+ until late last year, which was plenty capable of doing USB audio), but if you run out of CPU cycles(whatever the CPU is), then you need to either reduce your load or upgrade the processor.

As suggested, try one of the Linux Live CDs. See if the problem disappears...

~Phewl.

 

[jonjungel]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif stop arguing about theory that you probably don't understand. jitter on usb is a red herring.

I understand jitter theory just fine. What I don't know much about though, is the implementation details on how S/PDIF and USB are implemented. Most DACs probably have receiver chips from different manufacturers that all have their own characteristics.

That was why I referred to measurements that show USB to have more distortion than S/PDIF. All of you who said I was wrong, did not comment on this. Stereophile's measurements consistently show USB to have inferior performance to S/PDIF. I do not think this can be disputed.

Figures 8 and 10 at this page along with the corresponding text should explain what I mean. Here, John Atkinson is measuring SNDR on the analog output.

 

[linuxworks]

Quote:

Originally Posted by AudioPhewl /img/forum/go_quote.gif You have a PII/700mhz from 1994? Liar! PII didn't come out until several years later, and never touched 700mhz... PIII flipchips did 700mhz, however. But they weren't out until... erm, '99? Certainly 2000, but can't remember when they were released...

dell inspiron 8000. ok, so its a p3 instead of a p2. does that make ANY diff at all? ANY??? no of course not.

but I'm LYING so you get to score an argument point.

sheesh.

the point is still valid - ancient 10+ yr old machines can do usb audio just fine so there's no argument about it taking cycles - its a total non-issue.

HD video is still 'hard' on systems even by today's standards. dvd style video is mostly trivial. and audio - its not even sweat-breaking. not in the mid 90's and not today.

but of course, I'M LYING so you should ignore all that I say.........

(sheesh)

 

[rueyloon]

do does it mean a DAC/Amp with an optical input will always beat a Amp through line out only ?

how much difference does this "connection" makes ? if all this discussion is only about the effect on 5% of the performance it is moot to me, but if it is say, 50% then I guess I better pay attention

or does a DAC and AMP combination plays a major role ?

I'm looking into getting the govibe vulcan, DAC with optical input to use in between my computer and headphone (MS1), in the background, the EF 1 is also beckoning me. EF 1 has some good reviews, but it does not have a DAC nor a optical input. Will the RAW "goodness" of what ever that is left give a better performance ? is that possible ?

 

[vcoheda]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif USB AUDIO IS JUST FINE. it is not inferior to spdif.

USB always sounds worse that S/PDIF to me. all decent computer systems i have heard always convert the USB. there must be a reason for this.

 

[jonjungel]

Quote:

Originally Posted by rueyloon /img/forum/go_quote.gif do does it mean a DAC/Amp with an optical input will always beat a Amp through line out only ? how much difference does this "connection" makes ? if all this discussion is only about the effect on 5% of the performance it is moot to me, but if it is say, 50% then I guess I better pay attention or does a DAC and AMP combination plays a major role ? I'm looking into getting the govibe vulcan, DAC with optical input to use in between my computer and headphone (MS1), in the background, the EF 1 is also beckoning me. EF 1 has some good reviews, but it does not have a DAC nor a optical input. Will the RAW "goodness" of what ever that is left give a better performance ? is that possible ?

If you are using a digital source (like CD or computer) there is always a DAC in the signal path. If you use the analog output from the computer, the DAC is on the soundcard (or a chip on the motherboard if you don't have a separate soundcard). While some soundcards (quite expensive) have performance that can rival outboard DACs, a DAC integrated on the motherboard will most likely be very low quality in comparison. The same goes for DACs in most cheap CD-players.

If you compare the signal to noise and distortion ratio (SNDR) from a good DAC/Amp combo to the analog outputs on common motherboards, I'm sure the linear difference will be more than 50% (50% is just 3dB). Though this does not translate to "50% worse sound".

 

[AudioPhewl]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif dell inspiron 8000. ok, so its a p3 instead of a p2. does that make ANY diff at all? ANY??? no of course not. but I'm LYING so you get to score an argument point. sheesh. the point is still valid - ancient 10+ yr old machines can do usb audio just fine so there's no argument about it taking cycles - its a total non-issue. HD video is still 'hard' on systems even by today's standards. dvd style video is mostly trivial. and audio - its not even sweat-breaking. not in the mid 90's and not today. but of course, I'M LYING so you should ignore all that I say......... (sheesh)

Dude, I was pulling your leg. Hence the wink...

~Phewl.

 

[Currawong]

Funny this should come up, I tested it recently. However, only with my MacBook Pro and Audio-gd Compass, which is the first box I've had with both USB and optical inputs to the DAC.

The optical, using a mini-optical to Toslink Van Den Hul Optocoupler, was marginally more detailed than the USB connection. Noting that, I could hear clear differences between the Optocoupler and two cheap optical cables.

Of that, take what you may.

 

[I3eyond]

Quote:

Originally Posted by Currawong /img/forum/go_quote.gif Funny this should come up, I tested it recently. However, only with my MacBook Pro and Audio-gd Compass, which is the first box I've had with both USB and optical inputs to the DAC. The optical, using a mini-optical to Toslink Van Den Hul Optocoupler, was marginally more detailed than the USB connection. Noting that, I could hear clear differences between the Optocoupler and two cheap optical cables. Of that, take what you may.

DACs can be imperfect, taking away from what the source wanted us to hear. So what happens when a computer reads our minds, typing or writing for us because we're too lazy? What if the DAC misinterpreted you. How would you feel? Any system can fail, technology is not a stable one.

[cell phone voice recognizers]

I can't wait to get into vinyl so i can better experience Hendrix.

 

[krmathis]

Either one is fine to me.
For pure sound quality I pick USB. But use optical S/PDIF (AirPort Express) for mobility reasons.

 

[tacitapproval]

I discovered a potential problem with USB that has nothing to do with how the information is processed. My USB powered DAC (IBasso D3) picks up noise from the laptop's ac input. This can only be heard clearly at a high degree of amplification (beyond listening level), but it is there. So grounding issues are something to consider with USB.

 

[I3eyond]

Quote:

Originally Posted by tacitapproval /img/forum/go_quote.gif I discovered a potential problem with USB that has nothing to do with how the information is processed. My USB powered DAC (IBasso D3) picks up noise from the laptop's ac input. This can only be heard clearly at a high degree of amplification (beyond listening level), but it is there. So grounding issues are something to consider with USB.

Yeah, I was just really put off by how Hendrix sounded when i first started listening to him last night. Supposedly a classic, it's just too harsh on my digital setup.

Tubes, perhaps? I really do have my mind set on vinyl, however....

 

[Andrew_WOT]

Either one can be superior to the other, all depends on the quality of USB receiver and onboard card. Whichever does the better job doing SPDIF conversion wins. Except that onboard card can be susceptible to extra computer noise and depends on less than stellar computer power, when you take conversion out of the computer case you have more options, including dedicated PSU.