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  3. 159217-149317

USB sucks

USB really isn‘t the right connection between DAC and Server: depending on cables used, you get very different sound quality if the server manages to recognise the DAC at all. Some time ago I replaced my highly tuned Mac Mini (by now-defunct Mach2mini, running Puremusic via USB) with an Innuos Zenith Mk3. For starters I couldn‘t get the DAC (Antelope Zodiac Gold) and server to recognise each other, transmission from the server under USB2.0 wasn‘t possible because the server is Linux based (mind, both alledgedly support the USB2.0 standard) and when I finally got them to talk to each other (by using Artisansilvercables (pure silver) the sound quality was ho-hum. While I understand the conceptual attraction to have the master clock near the converter under asynchronous USB, the connection‘s vagaries (need for exact 90 Ohms impedance, proneness to IFR interference, need to properly shield the 5v power line, short cable runs) makes one wonder, why one wouldn‘t do better to update I2S or S/PDIF or at the higher end use AES/EBU. After more than 20 years of digital playback, the wide variety of outcomes from minor changes seems unacceptable.

Since then and after a lot of playing around I have replaced the silver cables by Uptone USPCB rigid connectors, inserted an Intona Isolator 2.0 and Schiit EITR converting USB to S/PDIF. Connection to the DAC is via Acoustic Revive DSIX powered by a Kingrex LPS.

The amount of back and forth to make all this work is mindboggling, depending on choice of USB cables (with and without separate 5V connection, short, thick and God-knows what else) is hard to believe for something called a standard interface and the differences in sound quality make any review of USB products arbitrary verging on meaningless.

Obviously S/PDIF gives you no native PCM or DSD but, hey, most recordings still are redbook, anyway.
Conversely it is plug and play although quality of the cable still matters but finally it got me the sound quality I was looking for. It may not be the future but nor should USB, given all the shortcomings. Why is the industry promoting a standard that clearly isn‘t fit for purpose?

Finally, I invite the Bits-are-bits naysayers to go on a similar journey, it just might prove to be educational.
antigrunge2
rixthetrick's avatar
rixthetrick
1,060 posts
 
@ubrwaltz - most everything I am reading now in forums (I use a PC based platform as a music server) is that Ethernet does resolve better than USB for the purposes of digital audio.

My next DAC purchase is most probably going to use that method in the future. I am however waiting to make my next move in DAC choice to better position myself in return on investment. The improvements are rapidly costing less as the technology develops across the board.
rixthetrick's avatar
rixthetrick
1,060 posts
 
@ lalitk1 - Of course I meant to type PLAYBACK, not payback...
hahaha a Freudian slip ( parapraxis ) perhaps..hahaha
antigrunge2 OP
1,460 posts
 
@rixthetrick
Can I suggest you use a whiff of Caig Deoxit on either end rather than resort to brute force?
uberwaltz's avatar
uberwaltz
13,381 posts
 
I did swap out the original fairly cheap Straightwire usb cabLe for the Audioquest Carbon for what I perceived to be a slight uptick in SQ.
The Carbon came free with the UltraRendu so I have zero skin in the game for any financially implied placebo effect imho.
relaks
63 posts
 
An USB DAC uses async digital transport with buffering. Then, it uses its own accurate internal clock generator to convert the digital data to analog.

So USB clock is not related to quality of sound whatsoever, nor cabling or connectors, etc!
@guyboisvert This all sounds nice on paper, but in real life buffering creates latency, a clock is highly susceptible to any noise that is mixed with the signal ( and there is a lot of such noise created by the motherboard, processor, EMI etc), and this is just the beginning.
We have the whole range of issues here, from the so called common notion of time to parasitic loops. The isochronous transfer used for real-time audio is far from perfect, it is not the same as a bulk protocol used for data. 
Having said that, a USB connection may sound impressively well. Or it may be really noisy, depending on the implementation and many factors. I have a ZEN Mk3 and an Aqua DAC, and the difference between USB cables is significant to say the least. 
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