Steaming via USB from PC to Dac

[eljr]

If you have a properly engineered DAC being fed by a computer the analog out of the DAC will be pristine. Benchmark Audio, years ago, proved this by making a cable that was something like 4 times longer than spec and just rife with errors. What happened? Their DAC played pristine music.

You've simply bumped into someone that doesn't actually trust their ears. At whatsbestforum SuperDad (Alex of Up-Tone Audio) I asked him if he would blind evaluate his own USB product. He said any day of the week. When it was offered to fly out to him and do this in his very own setup he didn't post again @ wbf for 18 months.

Tell your friend this: I have $8000 to their $1000, loser to pay expenses, in their own setup that they can't tell the difference between a well engineered DAC fed by a computer or fed by Micro-rendu 1.5 when blinded. The computer will be something bog standard like an Intel NUC or something like my Celeron 3150 based system that is totally silent or most likely a laptop.

When I say their setup it would be from their USB DAC on back. JRiver would be the playback application. After all this Covid business is done.

thing is, I know damned well I can hear no differences
heck, I can't tell the differance between using an echo link to a cheap Yamaha Dac from a $1,200 Dac. I can't even hear a differance using a junky Emotiva Dac.

and yeah, I am glad this Covid thing is over...

 

[eljr]

Streaming from my PC via USB or HDMI - does it make any difference?

Nope, it's one's and zero's either way.

 

[sterling shoote]

My contention is that there is nothing to deal with. It's optical not analog that is being streamed to the Dac.

Those that stream from a PC which does not have IEC958 or optical S/PDIF output will output digital files via usb to a usb DAC and these DACs do indeed "deal" with computer noise.

 

[eljr]

Those that stream from a PC which does not have IEC958 or optical S/PDIF output will be send digital files via usb to a usb DAC and these DACs do indeed "deal" with computer noise.

explain why and how, thanks

 

[sterling shoote]

explain why and how, thanks

OK, I have iTunes on my PC. If I want to play music in my iTunes Library to my Home Theatre System I have four routes: Airport Express, Creative Sound Blaster X-FI HD, Network Player (OPPO-205), or usb DAC (OPPO-205). Airport Express delivers optical S/PDIF at 16/44.1 to pre-pro, X-FI HD receives usb and converts to deliver optical S/PDIF up sampled to 24/96 to pre-pro, and PC delivers WLAN or usb to OPPO-205, which up samples to 24/192 and sends to analog preamplifier. The last methods present the best sound stage, tone, and detail from the AAC, ALAC, and AIFF files in iTunes; yet, the usb connection gives me direct control of iTunes from my cell phone used as a remote, or control from the computer eliminating monitor use for excessive scrolling on my TV.

 

[eljr]

OK, I have iTunes on my PC. If I want to play music in my iTunes Library to my Home Theatre System I have four routes: Airport Express, Creative Sound Blaster X-FI HD, Network Player (OPPO-205), or usb DAC (OPPO-205). Airport Express delivers optical S/PDIF at 16/44.1 to pre-pro, X-FI HD receives usb and converts to deliver optical S/PDIF up sampled to 24/96 to pre-pro, and PC delivers WLAN or usb to OPPO-205, which up samples to 24/192 and sends to analog preamplifier. The last methods present the best sound stage, tone, and detail from the AAC, ALAC, and AIFF files in iTunes; yet, the usb connection gives me direct control of iTunes from my cell phone used as a remote, or control from the computer eliminating monitor use for excessive scrolling on my TV.

OK, but this post does not answer my question. How does a USB connection transmit noise?

 

[sterling shoote]

OK, but this post does not answer my question. How does a USB connection transmit noise?

The usb DAC deals with jitter. In the case of my OPPO, it virtually eliminates it. Jitter is essentially noise produced when word clocks of digital sending and receiving units are not in sync.

 

[eljr]

the usb DAC deals with jitter. In the case of my OPPO, it virtually eliminates it.

what the truck, dude, so your saying there is jitter that is only eliminated in your DAC... come on man, answer the question.

 

[sterling shoote]

what the truck, dude, so your saying there is jitter that is only eliminated in your DAC... come on man, answer the question.

Todays usb DACs are designed to reduce jitter. Jitter is noise produced when the word clock of the digital sending device is not in sync with digital receiving device. This is the noise the usb DAC is "dealing" with. My OPPO has a usb DAC that deals with jitter very effectively, in fact state-of-the-art effectively for HDMI transmission, but that's another subject.

 

[eljr]

Todays usb DACs are designed to reduce jitter. Jitter is noise produced when the word clock of the digital sending device is not in sync with digital receiving device.

OK, so then let me ask this... does a DAC nested in the same box as the streamer experience the same jitter?

and if so, what completely eliminates jitter?

 

[sterling shoote]

OK, so then let me ask this... does a DAC nested in the same box as the streamer experience the same jitter?

and if so, what completely eliminates jitter?

Nothing yet completely eliminates jitter. The DAC in a streamer, dedicated or PC, sends an analog signal, so there's no jitter issue, since there's no transmission of digital from a sending unit to a receiving unit. At one time though, folks just output analog from their computer. However, computer DACs were seen as inferior so usb or S/PDIF transmission to external sound cards and now high quality DACs has become popular. Jitter was an issue then, but not now.

 

[eljr]

Nothing yet completely eliminates jitter. The DAC in a streamer, dedicated or PC, is sending an analog signal, so there's no jitter issue, since there's no transmission of digital from a sending and receiving unit. At one time, folks just output analog from their computer. However, computer DACS were seen as inferior si usb or S/PDIF transmission to external sound cards and now high quality DACs has become popular. Jitter was an issue then, but not now.

So then you are contradicting yourself...

You are now saying that running a digital signal from a PC to a Dac will not induce noise as Dac's are so good.

 

[sterling shoote]

So then you are contradicting yourself...

You are now saying that running a digital signal from a PC to a Dac will not induce noise as Dac's are so good.

That's what I've always said, read my first post. The usb DACs deal with noise (jitter); but, long ago, when digital transmission via usb or S/PDIF connection from PC to receiving units was a novel process, jitter was an issue.

 

[jinjuku]

OK, but this post does not answer my question. How does a USB connection transmit noise?

USB can transmit noise over the ground plane. The DAC's job is to isolate itself. This is already done with modern off the shelf USB implementations however. Amir at ASR measured a Schiit DAC that didn't do Schiit to isolate and it showed up in measurements. Especially the 8Khz USB clock.

 

[jinjuku]

So then you are contradicting yourself...

You are now saying that running a digital signal from a PC to a Dac will not induce noise as Dac's are so good.

There is no audio clock on the USB packet stream. USB supplies it's own clocking for it's own packets. When packets hit the DAC the DAC decodes the packets, reads the clocking information for the audio it's receiving and reconstructs the audio clock and applies it. The more accurately it can do this the lower the Jitter.

 

[jinjuku]

long ago, when digital transmission via usb or S/PDIF connection from PC to receiving units was a novel process, jitter was an issue.

And the reason for this is that the connection was synchronous and both end points had to establish a clock together. If one side was a bit off in it's timing you had jitter. USB is asynch in this regard. So is Ethernet.

 

[jinjuku]

Go to Youtube and look up some tutorials on 'Clock Domain Boundaries' It's worth a viewing.

 

[eljr]

USB can transmit noise over the ground plane. The DAC's job is to isolate itself. This is already done with modern off the shelf USB implementations however. Amir at ASR measured a Schiit DAC that didn't do Schiit to isolate and it showed up in measurements. Especially the 8Khz USB clock.

Is this noise eliminated if the Dac and streamer are both in the same box?

 

[MTVhike]

Do the same comments regarding noise and jitter apply if there is a USB - digital optical or coaxial device which then connects to my AVR's own DAC?

 

[jinjuku]

Is this noise eliminated if the Dac and streamer are both in the same box?

It has to be. But there is still a databus feeding the dac portion. A streamer for all intents and purposes is a computer. It has a CPU, it has volatile and non-volatile storage, it has I/O and many are based on the Linux OS.

I personally like rolling my own streamer with a totally silent PC running Windows 10 and Jriver. The reasons have to do with Jim and co's development approach:

They abstract their software in such a way that I can take advantage of modern hardware. What I mean by that is:

My setup is 10GB Optical Ethernet. It's a passively cooled Celeron 3150 with SSD storage and a silent PSU. The box makes zero noise. It cost about the same as the Micro-Rendu but I get the following:

As a matter of fact my entire 10GB setup (server nic, switch, end point nic) was $210. less than 1/3 to 1/8th of 'audiophile' solutions.

Ability to buffer up to 1GB of data. I concatenated an entire album in Audacity and converted to flac for a 400MB 'track'. Combined with 10GB Ethernet I was able to start playback in JRiver and by the time I pulled the plug (the worlds largest possible source of Jitter) the entire album was already buffered locally and the entire album played back with zero network connectivity.

Ability to apply convolution.