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
guyboisvert
42 posts
 
@antigrunge2 you don't seem to understand how USB works (like a charm by the way) and digital transport in general...
The cables DO NOTHING (unless completely broken!), it's just low speed digital transport with checksumming.  The DAC must run in async mode (most of them do now) and use an input buffer.  Nothing very special here, an easy technology mastered since a long time...

So you may have a badly USB implemented DAC... or you are a reseller that wants to rip people....
I have a Rega USB DAC and it works like a charm.  My friend has an Ayre QB-9, works very well too.  Mine is hooked to a raspberry pi (Raspbian + Volumio), and i sometimes use my Lenovo laptop too (Ubuntu 20.04 + mpd): It works with both flawlessly and it is recognized right out of the box.  My friend's QB9 is hooked to an old Intel Atom Mini-ITX board who runs Debian (mpd), again works flawlessly.  I could go on and on like that for every friends i have that use USB DAC...

I have a really goog laugh when i see people throwing money to trash by buying expensive USB cables!  Better put your money elsewhere...
guyboisvert
42 posts
 
@sgreg1  "none of the noise people complain about from usb"
HA HA HA! Noise from a digital transport, that's the most stupid thing i read since a long time!!!  You can transfer terabytes of data with USB WITHOUT ANY ERRORS using a simple cheap USB cable...  That tells it all!

And when you send no data, you simply hear silence!  Noise has nothing to do with that!!!  I'll repeat again, and repeat after me:  USB is a simple serial digital transport with checksumming and buffering!
guyboisvert
42 posts
 
@djones51  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!  Forget about "jitter", reclocking or any other plain stupidity...  So forget about stupid "audio grade" USB, put your money elsewhere...
jaudio1
121 posts
 
I have an Aurender Music Server / Streamer.  It only outputs USB.  Using a Curious Evolved USB Cable I have never had a single issue with any DAC recognizing the USB connection...DAC's used are Schiit Gungnir MB, Chord Qutest, MHDT Labs Pagoda, the DAC in my old Parasound P6....never an issue and the sound is fantastic.  If you just hate USB you can buy a USB reclocker / SPIDF converter that you can go USB in and COAXIL or I2S out.  You place this between your server/computer and dac.
loke
2 posts
 
It might be that a ground loop can cause problems, so try an optical USB-extender. I have been using Linux (Kubuntu 18.04) - using Jack - with Prism Audio Titan for quite some time and I have never had a hick-up. I find that Linux cause much less hassle than Windows.
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