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DaveK
19-08-2009, 10:08
Hi Guys,
Just a brief posting from me this time (there's a novelty! :) ).
I recently 'invested' in a Belkin Home Cinema USB lead (higher price and slightly thicker = higher quality ??) to see if it added anything to the quality of sound from PC to Caimanised 7520.
Result: - no perceivable difference from bog standard USB lead.
Cheers,

Steve Toy
19-08-2009, 10:50
Dave, I think you know why perhaps there is no perceivable difference. Where does the sound ultimately emerge from?

DaveK
19-08-2009, 11:58
Dave, I think you know why perhaps there is no perceivable difference. Where does the sound ultimately emerge from?

Hi Steve,
Stop it, you're floggin' a dead 'orse!! :lolsign:
It's not very often I get to correct a luminary like you so forgive me if I relish it :) :ner::ner::ner::ner: . If you had been closely following the Mike Homar Digital Cable thread you would know that I have tried a sample and then passed it on to GazJam (so I am now sans said cable). When I first put it into my system, between CD player and Caimanised 7520 the improvement was little short of mind blowing. My posting stated that it was the best pound per sound quailty upgrade I'd ever experienced and I have subsequently ordered two, one for CD and one for Sky box, big money for me!
So, ...... if Mike's cable is capable of such a dramatic improvement then surely it is possible (though perhaps improbable) for a USB lead to demonstrate a similar, or at least noticeable, improvement. And yes, before you ask, the speakers were on the side board for both trials, so :ner::ner::ner::ner: therefore speaker position was/is irrelevant in this context, so there!!
Have a good day, you can't win 'em all. :lolsign:
Cheers,

Alex_UK
19-08-2009, 12:15
Hi Dave,
Although I upgraded the tat cable I had to an "Audio" USB lead from Belkin, there was so much else going on in the system at the same time I have no idea if it made any difference or not, though just the fact that the plugs are gold plated, and the connection much snugger, makes me happy I've got a better physical link between the two.

When I get the chance I would be interested to do an A/B myself, but can any of the experts out there provide a theory on why a better USB cable should or indeed couldn't make a difference? From my mains cable/conditioner experiences I'll try anything now, and happily become a converted sceptic, but I'd like to know the theory behind it - to my simple mind, the digital information either gets to the DAC or it doesn't? Or, if bits of it get lost, does the DAC "make up" what it misses?

DSJR
19-08-2009, 13:10
Come on fella's, you know all digital is total cr@p.

"Analogue" is much closer to what we *think* it should be isn't it? ;)

I mean, we *love* the several percent tracing distortion, the compression and limited signal to noise ratio. It makes music reproduction sooooooooo much more "musical" and "organic" and the compression makes "deeeetail" so much easier to hear...... :D :D :D

Apologies, couldn't resist it... Just use a cable properly designed for the job and choose equipment that doesn't exhibit silly "top end" impedance mis-matches and you won't go wrong....

:gig:

Labarum
20-08-2009, 05:47
Ben Franklin did the job with a wet kite string!

DaveK
20-08-2009, 11:00
Hi Dave,
Although I upgraded the tat cable I had to an "Audio" USB lead from Belkin, there was so much else going on in the system at the same time I have no idea if it made any difference or not, though just the fact that the plugs are gold plated, and the connection much snugger, makes me happy I've got a better physical link between the two.

When I get the chance I would be interested to do an A/B myself, but can any of the experts out there provide a theory on why a better USB cable should or indeed couldn't make a difference? From my mains cable/conditioner experiences I'll try anything now, and happily become a converted sceptic, but I'd like to know the theory behind it - to my simple mind, the digital information either gets to the DAC or it doesn't? Or, if bits of it get lost, does the DAC "make up" what it misses?

Hi Alex,
Just a brief update:
Last night I listened again with new USB lead and now I'm not so sure about the lack of improvement - even good memories sometimes play tricks and mine certainly ain't good now :lol: . Would need to do another A to B comparison but can't be arsed - having installed the new, pricey, USB lead I aint gonna change it - at worst it is as good as the cheap one and at best it might be better - nothing to gain.
Cheers,

DaveK
20-08-2009, 11:04
Just use a cable properly designed for the job and choose equipment that doesn't exhibit silly "top end" impedance mis-matches and you won't go wrong....

:gig:

Hi Dave,
I would/might if I understood what it meant and how to implement the knowledge :scratch: :scratch: :lolsign: .
Cheers,

lovejoy
20-08-2009, 11:08
Hi Dave,
How does your new USB cable compare with your optical/coax connection?

USB was never designed as an audio interface, so all data is transmitted in packets, which means that for a real-time application, such as audio, it's quite possible to produce all sorts of timing errors, unless things are buffered properly. The quality of the cable between the PC and the DAC should be the last of your worries.

Unlike SPDIF/Optical which IS an audio interface where the cable will make a difference in terms of signal reflections in coax cable and light refractive index in optical cable.

DaveK
20-08-2009, 11:27
Hi Rich,
Thanks for that - wish I understood more about data transmission, packets and such - I feel a bit like a cave man asking a visiting spaceman to explain an atomic bomb - I hear all but understand very little :doh::doh: .
In answer to your question, as my PC has oodles of 'Outs', including Line, USB, Firewire, toslink and co-ax, I could readily do a comparison keeping everything constant except the communication line between PC and StanDAC but I ain't really motivated. My Standac is the centre of my auio hub and it's inputs are not really available for change, i.e. given my outputs they pretty much fall into pairs if you follow me.
However, if it contributes to the pool of knowledge or experience on the forum I would be willing to do a comparison but remember I don't have the most sensitive or discerning ears in the parish :lol: .
Cheers.

NRG
20-08-2009, 15:47
The USB spec always had a stream pipe mode from day 1. It allows for Isochronous transmission of time dependant data such as audio and video. It could be argued it's much more of an 'audio' interface than SPDIF which I read was initial intended for use in the Lab as a quick n dirty test interface.

Although there's no recovery of data in this mode the data packets are CRC protected and given the differential signalling design of USB should provide a much more reliable and accurate data stream. Compare this to SPDIF which looks much more like a single ended FM data stream with minimal single bit parity protection and variable impedance mismatches due to the use of phono connectors...


The only thing I can think that would make a difference between USB cables is if there is an interference problem and the shielding is better in one cable than the other. USB 2 cables are better in this respect as USB 2 supports a high speed transmission mode and requires better shielding.

Alexxus
21-08-2009, 19:02
Interesting read. Thanks, Neal :respect: