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Topic: S/PDIF output from PC to DAC? (Read 17700 times) previous topic - next topic
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S/PDIF output from PC to DAC?

Hi,

I'm considering getting the Musical Fidelity M1 DAC, and I have one important question upon which my purchase depends.

Since M1's USB input is actually quite bad for the price, in that it only supports up to 16-bit/48kHz signals, I've been considering connecting the DAC to my PC's onboard S/PDIF optical out. Now: how much does the quality of S/PDIF out depend on the quality of the (onboard) soundcard and the motherboard in general? Will there be additional jitter and/or interference caused by my PC's circuitry?

I have a Realtek ALC888 chip, and the motherboard is MSI K9N2 Platinum.

Thanks for help.

S/PDIF output from PC to DAC?

Reply #1
no, that works best.


S/PDIF output from PC to DAC?

Reply #3
FWIW, http://www.musicalfidelity.com/m1dac/  claims these specs:

1x XLR AES balanced digital input
1x RCA coaxial connector SPDIF 32-192 kbps (16-24 bit stereo PCM)
1x TOSLINK optical connector 32-96 kbps (16-24 bit stereo PCM)
1x USB type ‘B’ connector for computer/PDA - 16-24 bits, 32-96 kbps (Determined by source file/computer settings)

(Edit: of course your dealer might be pushing an old one ... hoping you'll never notice the difference  )

S/PDIF output from PC to DAC?

Reply #4
Someone should tell them that confusing kilohertz with kilobits per second looks awful on a website that features exclusively hi-fi equipment…


S/PDIF output from PC to DAC?

Reply #6
Someone should tell them that confusing kilohertz with kilobits per second looks awful on a website that features exclusively hi-fi equipment…


Yeah, an audio(phile) company that makes digital audio products doesn't know the difference between kbps and kHz... Makes me kinda not want to buy their DAC

S/PDIF output from PC to DAC?

Reply #7
Here's cult hero Monty making the same "mistake".

http://xiphmont.livejournal.com/58294.html

Is there really a difference, other than 'kbps' is the more common terminology?


Edit:

Wow, what was I thinking? There is a big difference.

192 kHz is correct, while 192 kbps would be completely wrong. The sampling rate of CD audio is 44100 samples per second, or 44.1 kHz. At 2x16-bits per sample, the bitrate of CD audio is 1411.2 kbps.

When speaking of 24-bit/192 kHz they are indeed talking about the sampling rate, not the bitrate. I think the confusion arises from thinking about lossy encoding, which is typically expressed in kbps and 192 kbps happens to be a common CBR for Mp3 encoding.

S/PDIF output from PC to DAC?

Reply #8
Well, I would understand an end user being confused, but for a manufacturer to present such bummer on its presentation web page...

S/PDIF output from PC to DAC?

Reply #9
Well, I would understand an end user being confused, but for a manufacturer to present such bummer on its presentation web page...


That's just a sign that the electrical engineers have so much pride that they outright refuse to even read the marketing department's mumbojumbo snakeoil spin 

Well seriously, I could have read the same thing over and over again without noticing it. If you don't notice it first or second time, you read it as you remember it.

S/PDIF output from PC to DAC?

Reply #10
"192 kHz" is not wrong. You are the ones who are confused.


S/PDIF output from PC to DAC?

Reply #12
Strange, it seems that they use Khz in the 'DESIGN + BUILD' section, but then use 'kbps' in the 'SPECIFICATIONS' section.

Quote
The M1 CLiC happily handles the following formats: FLAC (up to 24bit/192kHz wired; 24bit/96kHz wireless); WMA/9 (up to 16bit/48Hz); AAC and HE-AAC (up to 24bit/96Hz); LPCM (up to 24bit/192kHz wired; 24bit/96kHz wireless); Ogg vorbis (up to 16bit/32kHz) and MP3 (up to 16bit/48kHz).


Only up to 16bit/32kHz for Ogg Vorbis? Why???


S/PDIF output from PC to DAC?

Reply #14
Hi,

I'm considering getting the Musical Fidelity M1 DAC, and I have one important question upon which my purchase depends.

Since M1's USB input is actually quite bad for the price, in that it only supports up to 16-bit/48kHz signals,


Also pretty horrific from a price/performance viewpoint.

Quote
I've been considering connecting the DAC to my PC's onboard S/PDIF optical out. Now: how much does the quality of S/PDIF out depend on the quality of the (onboard) soundcard and the motherboard in general? Will there be additional jitter and/or interference caused
by my PC's circuitry?


For the price of he MF M1 DAC, one would hope that it has good jitter resistance.

Jitter might be audio's  bogey man, a fable told to naive people to scare them.


Quote
I have a Realtek ALC888 chip, and the motherboard is MSI K9N2 Platinum.



Here's some online tech tests (I translated from Russian using Chrome)

Audio Rightmark ALC 888 on MSI system board

Really look pretty darn good to me!

What sounds bad about this setup now?

 

S/PDIF output from PC to DAC?

Reply #15
Hi,

I'm considering getting the Musical Fidelity M1 DAC, and I have one important question upon which my purchase depends.

Since M1's USB input is actually quite bad for the price, in that it only supports up to 16-bit/48kHz signals, I've been considering connecting the DAC to my PC's onboard S/PDIF optical out. Now: how much does the quality of S/PDIF out depend on the quality of the (onboard) soundcard and the motherboard in general? Will there be additional jitter and/or interference caused by my PC's circuitry?

I have a Realtek ALC888 chip, and the motherboard is MSI K9N2 Platinum.

Thanks for help.


From the experience with my rig (Asus A8V-X onboard S/PDIF -->Asus Toslink bracket -->Optical cable -->Fiio D3 (dac) -->RCA cable (Belkin) -->Edifier M3400 (2.1 speakers),  I believe there´s some kind of interaction between the  internal EMI/RFI of the PC and the Toslink connector,  generating audible noise from the speakers.

S/PDIF output from PC to DAC?

Reply #16
From the experience with my rig (Asus A8V-X onboard S/PDIF -->Asus Toslink bracket -->Optical cable -->Fiio D3 (dac) -->RCA cable (Belkin) -->Edifier M3400 (2.1 speakers),  I believe there´s some kind of interaction between the  internal EMI/RFI of the PC and the Toslink connector,  generating audible noise from the speakers.

I somehow doubt that. You should run RMAA to verify.

S/PDIF output from PC to DAC?

Reply #17
The only way noise from the PC could end up in a TOSLink S/PDIF stream is if the mobo audio chip was doing a D/A->A/D conversion...highly unlikely.

Much more likely is that the interference is occurring on the USB power that the D3 is running on.
"Not sure what the question is, but the answer is probably no."

S/PDIF output from PC to DAC?

Reply #18
Hi,

I'm considering getting the Musical Fidelity M1 DAC, and I have one important question upon which my purchase depends.

Since M1's USB input is actually quite bad for the price, in that it only supports up to 16-bit/48kHz signals, I've been considering connecting the DAC to my PC's onboard S/PDIF optical out. Now: how much does the quality of S/PDIF out depend on the quality of the (onboard) soundcard and the motherboard in general? Will there be additional jitter and/or interference caused by my PC's circuitry?

I have a Realtek ALC888 chip, and the motherboard is MSI K9N2 Platinum.

Thanks for help.


From the experience with my rig (Asus A8V-X onboard S/PDIF -->Asus Toslink bracket -->Optical cable -->Fiio D3 (dac) -->RCA cable (Belkin) -->Edifier M3400 (2.1 speakers),  I believe there´s some kind of interaction between the  internal EMI/RFI of the PC and the Toslink connector,  generating audible noise from the speakers.


What is the nature of the noise? When do you hear it?

S/PDIF output from PC to DAC?

Reply #19
What is the nature of the noise? When do you hear it?


Hiss. 

First, I took off a 120mm fan that was at the back of the case.  Later I´ve wrapped up the toslink  bracket, five or six times, with tinfoil, just making holes to pass the cables.  After that, not only the hiss is  gonne, but sound quality increased so much, that is difficult to me stop listenning to jazz at Grooveshark...
Well, maybe  it´s all in my mind, I don´t know, but definetly I´m enjoyng it !

P.S.: I believed optical connections were noiseless, until I read this post, that seemed to make sense to me:

"EMI/RFI will not travel down an optical link."

(reply)

"EMI/RFI will not travel down the optical link. However, the timing of the optical pulses is affected by EMI/RFI inside the source box and when the pulses are reconverted to electrical signals at the DAC this EMI/RFI will be resurrected, albeit in an altered form."

Tony Lauck  at http://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=109574

(any misunderstandings are due to my ignorance in electricity and in english, so forget)

S/PDIF output from PC to DAC?

Reply #20
What is the nature of the noise? When do you hear it?


Hiss. 

First, I took off a 120mm fan that was at the back of the case.  Later I´ve wrapped up the toslink  bracket, five or six times, with tinfoil, just making holes to pass the cables.  After that, not only the hiss is  gonne, but sound quality increased so much, that is difficult to me stop listenning to jazz at Grooveshark...
Well, maybe  it´s all in my mind, I don´t know, but definetly I´m enjoyng it !

Wrapping an optical cable in tinfoil will do absolutely nothing to improve the signal or reduce jitter. So yeah it's all in your mind.

You might not care whether or not the "improvement" is placebo, but most others here won't appreciate fud like this being spread. So please either show some measurements of the reduced noise level (if you can hear it then RMAA will definitely show it) or stop violating TOS8.

S/PDIF output from PC to DAC?

Reply #21
What is the nature of the noise? When do you hear it?


Hiss. 

First, I took off a 120mm fan that was at the back of the case.  Later I´ve wrapped up the toslink  bracket, five or six times, with tinfoil, just making holes to pass the cables.  After that, not only the hiss is  gonne, but sound quality increased so much, that is difficult to me stop listenning to jazz at Grooveshark...
Well, maybe  it´s all in my mind, I don´t know, but definetly I´m enjoyng it !

P.S.: I believed optical connections were noiseless, until I read this post, that seemed to make sense to me:

"EMI/RFI will not travel down an optical link."

(reply)

"EMI/RFI will not travel down the optical link. However, the timing of the optical pulses is affected by EMI/RFI inside the source box and when the pulses are reconverted to electrical signals at the DAC this EMI/RFI will be resurrected, albeit in an altered form."

Tony Lauck  at http://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=109574

(any misunderstandings are due to my ignorance in electricity and in english, so forget)


The foil isn't making any differences in the timing of the pulses.  Removing any possible effects of minor pulse timing variations is the job of the DAC.

I would have to see some reliable tests to confirm what I've seen so far.  I've been working with TOSLink for about decade and never saw or heard anything like this.

S/PDIF output from PC to DAC?

Reply #22
From: http://www.digikey.com/Web%20Export/Suppli...df?redirected=1

Precautions for Using TOSLINK
................................................................
................................................................
................................................................

The case for the TOSLINK (simplex) optical receiving module and (duplex) optical transceiver module is made of conductive
plastic.
The case is designed to provide shielding against noise when the reinforcing pin at the front of the module is grounded. When the
module is used, this pin should be connected to the signal ground.
Since the case for the optical receiving module and optical transceiver module has a resistance of several tens of ohms, ensure that the
case does not touch the power line or any other circuits.
Generally, the use of optical transmission devices is considered to improve noise resistance.
While optical fibers are certainly not affected by noise, optical modules, particularly receiver modules, are comparatively easily affected
by noise because they handle such minute current signals.

To improve noise resistance, the TOSLINK case is treated to make it conductive. However, since the signal output from the optical
receiving modules photodiode is a minute current signal, in some environments simply shielding the case will not protect against noise.
When using a TOSLINK device, conduct live tests to check noise resistance.
A simple noise filter is mandatory for the power lines for the TOSLINK optical receiving module and optical transceiver module.
However, in the case of significant power supply ripples, further filter reinforcement is also necessary
. In addition, when the optical
module is placed in a location susceptible to emission noise, Toshiba recommends covering the optical module and power supply filter
with a metal cover to enhance the shielding.


Of course this not means that there´s noise interacting with my optical connection, or that it is audible.  On the other hand, I´ll try to make the RMAA tests,  whatever they be, and post them here (but only if they confirm my suspicions...)

S/PDIF output from PC to DAC?

Reply #23
On the other hand, I´ll try to make the RMAA tests,  whatever they be, and post them here (but only if they confirm my suspicions...)

Please post the results regardless of what they confirm.

S/PDIF output from PC to DAC?

Reply #24
From: http://www.digikey.com/Web%20Export/Suppli...df?redirected=1
The case for the TOSLINK (simplex) optical receiving module and (duplex) optical transceiver module is made of conductive
plastic.
The case is designed to provide shielding against noise when the reinforcing pin at the front of the module is grounded. When the module is used, this pin should be connected to the signal ground.


The passage refers to the electrical shielding (in noisy environments) of the *receiver*  (where the optically generated *electrical* currents really are initially very small at the detector front end). You are trying to shield the transmitter - a totally different scenario.

Download RMAA here: http://audio.rightmark.org/download.shtml

Quote
On the other hand, I´ll try to make the RMAA tests, whatever they be, and post them here (but only if they confirm my suspicions...)

Ok that is just being silly. Unless that's a joke then it shows that you have no interest at all in disseminating the truth, and a on the contrary, no qualms as all about spreading FUD!.