[plonter]

has anyone used both method of digital input?   i have a little "situation" with my usb input in the um dac.   
I was also discussing this in the computer audio forum but  since i didn't get a full answer to my situation i though i as well put it on here too. just interested what headroom and you guys have to say about this.
 
anyway,this is the thing.   i have a marantz cd5001 cd player which i use as a transport for my um dac for a long time now and very happy with it.  lately i tried to use my computer as a transport because it is much more comfortable to use,all the music is in the palm of my hand and i don't need to switch cd's.
i am using win7 with foobar and wasapi for bitperfect stream through usb.  the first thing i noticed when using this computer setup is that the treble is sharper,and hotter than when i use the optical or coax input thourgh the marantz player.  this is very noticable,and i actually need to EQ the treble down by a notch to balance things out a little.      I am currently using the kimber usb cable,but the sound was the same with other usb cables i tried so the problem is not the cable.  
my general feeling is that the marantz output is more "correct".  when i tried a cheap dvd player optical out the sound was the same as the marantz so this is the basis for my speculation that the marantz is more correct.
 
first of all,i would like to get some ideas of what can be the cause for this differnece in sound..and i would also like to hear some opinions of people who used both usb and coax/optical, did you experience the same thing i did?  or did it sound the same to you?
 
since jitter is not suppsed to be a big issue with the um dac,the only logical reason i can find  for this difference is somehow related to the usb reciever chip in the um dac.  but i am getting a hard time to believe that the PCM2902 does a faulty job with the usb to s/pdif conversion...not something you would excpect from a dac in this level which corporates the best cirrus and analog devices dac and async' chips.
 
I would be happy to hear any thought on this.
 

 

[aimlink]

I've tried USB and optical from my Mac.  I haven't heard any differences.

 

[noris83]

There is a bit of a difference but nothing as drastic as hotter treble. Let me A/B again before commenting further.

 

[superjohny]

i found usb provides better sounding than optical, more focused and forward mids and yet dynamic.
 
maybe this is because of a bad quality toslink cable  

 

[aimlink]

 
Quote:

i found usb provides better sounding than optical, more focused and forward mids and yet dynamic.
 
maybe this is because of a bad quality toslink cable  

Bad quality toslink?  Oh boy... I'm not one who has experienced that sort of stuff where a bad toslink could affect the music only in how focused it is and how forward the mids are.  I find this very far reaching.  I'd more look to the interface, rather than the connections.
 
Anyway, I fail to hear a difference personally.

 

[noris83]

 
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Ok I did some A/B with mostly AIFF but some 192-320 mp3s. Genres varied from classical to jazz and a few pop tracks.
 
Source and interconnects: iMac, Monster optical , Belkin usb, iTunes, PeakPro 5
Headphones: Beyer T1
 
Here are my observations: Optical has better treble extension and more air. USB has slightly more forward mids. Bass is about the same. Using PeakPro, instrument separation with optical was very slightly improved over iTunes while USB showed no change. 
 
Some of my results are likely due to the quality of equipment. I'm only using a Belkin gold USB cable so it's quite possible a Kimber or other high-end cable will give you similar results to optical. I tried a cheapie optical cable and found it to have less detail than my Belkin USB so clearly interconnects play a big part here.
 
Conclusions: I'm not sure anyone would really notice a tremendous difference using optical or usb. I had to critically listen to about 10 different tracks too many times to count and the difference is barely perceptible even with the T1s. The rolled off highs and focused mids from the USB actually sounded better with low bit-rate tracks. Using 192 and 320 mp3s the optical cable often made the tracks sound trashy with harsh highs. USB also compensated a bit for the "smile EQ effect" used in many of todays pop tracks where highs and lows are accentuated. 
 
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[aimlink]

Quote:

 
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Conclusions: I'm not sure anyone would really notice a tremendous difference using optical or usb. I had to critically listen to about 10 different tracks too many times to count and the difference is barely perceptible even with the T1s. The rolled off highs and focused mids from the USB actually sounded better with low bit-rate tracks. Using 192 and 320 mp3s the optical cable often made the tracks sound trashy with harsh highs. USB also compensated a bit for the "smile EQ effect" used in many of todays pop tracks where highs and lows are accentuated. 
 
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[/size]

Sounds like you'd fail one of those DBT's then. 

 

[noris83]

Quote:

Quote:

Sounds like you'd fail one of those DBT's then. 

I totally would.

 

[plonter]

I guess i got jitter problem with my computer..can't think of other reason for this.   the marantz cd player sound so much better and balanced  in comparison.  I guess my computer usb puts out so much jitter that even the um dac can't handle.