2. digital
  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
 
@steakster - thanks for that, did a lot of reading. Learnt new things, brilliant - cheers
clarinetmonster2's avatar
clarinetmonster2
201 posts
 
I noticed a significant upgrade in clarity going from Usb DACs in the 1-2k range to a dedicated streamer/dac with Ethernet in and I was using a well regarded usb reclocker etc. The other thing I did was add an Ethernet extender so there is no physical connection to the noisy router. Because of this I was able to use a very short run of high quality Ethernet cable to the streamer. Doing AB comparisons, there was no comparison. Ethernet cable direct to the modem had less clarity and more grit in the sound. 
ianderson
91 posts
 
I’ve played with different transmission types and they all have there pros and cons and work well. USB is fine from my experience. Like to OP I had a Innuos.... Zen and Zenith in my system. (Ended up keeping the Zenith) I’ve A/B’d many cables from Inakustic, Qudioquest, Acoustic BBQ, Ocelia, Cardas and they all worked without a hiccup in either and Aqua or Ayre DAC.

Might the OP have a faulty port at one end?
antigrunge2 OP
1,366 posts
 
@ianderson 

the Zodiac Platinum USB port isue on Linux is fixable by inserting an USB Hub. The point of the thread is the variability of outcomes on the USB connection as a function of different cables, reclocking and galvanic insulation. The range of outcomes makes reviews of USB Dacs borderline meaningless. While one might get lucky with a high quality connection out of the box, nobody can know quite how good relative to various ways of tuning that connection actually is. Not great for an industry standard
djones51
4,947 posts
 
There is a Audio Device Class for USB. 

The Audio Device Class Definition applies to all devices or functions embedded in composite devices that are used to manipulate audio, voice, and sound-related functionality. This includes both audio data (analog and digital) and the functionality that is used to directly control the audio environment, such as Volume and Tone Control. 

Don't fault the USB standard for manufacturers who fail to follow it or do so incompetently.
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