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15 USB/SPDIF converters shootout

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yup, they all suck, as do speakers and microphones. Really, the only solution is to listen only to live, un-amplified music. Of course, this would leave out Miles Davis, so this solution totally sucks as well.


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The practical take away is that is no silver bullet, no single inherently superior protocol/system/cable etc.

I thought the practical take away here was that Internet Fora are pointless for this kind of discussion...


Eloise

---

...in my opinion / experience...

While I agree "Everything may matter" working out what actually affects the sound is a trickier thing.

And I agree "Trust your ears" but equally don't allow them to fool you - trust them with a bit of skepticism.

keep your mind open... But mind your brain doesn't fall out.

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So, to summarize:

 

1. s/pdif, usb, rca, aes-ebu, and st fiber (perhaps bnc too- not clear on that) all suck.

2. s/pdif converters suck.

3. running straight from the computer's usb buss to a usb dac sucks.

 

I enjoy reading these posts for educational purposes, but for those of us who are not electrical engineers, audio component designers or industry insiders, what is the practical "take away" from all this discussion?

 

Emphasis on the word "practical".

Sounds like the only reliable answer is "it depends". Still happy with my little m-link anyhow.

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Hey guys, why no mention or love for ethernet here? There are some methods, both present and yet to be explored, which skip most all the problems of USB and S/PDIF.

 

You will find good ethernet discussions in this forum.

Just not the norm yet...

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Hey guys, why no mention or love for ethernet here? There are some methods, both present and yet to be explored, which skip most all the problems of USB and S/PDIF.

 

I wonder whether Ethernet streaming will lead to a proliferation of $$$ audiophile RJ45 cables.

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Synopis:

 

USB internal to a DAC, properly implemented is essentially perfect

Ethernet, internal to a DAC, properly implemented can also be essentially perfect

FireWire, internal to a DAC, properly implemented can also be essentially perfect

 

An external USB-SPDIF can be essentially perfect as well, but only with a very sophisticated, fully asynchronous SPDIF receiver in the DAC, there are only a very few DACs which incorporate this technology.

 

All of the above assumes two channel audio, at rates up to 24/192, although higher rates are supported by some devices as well. As with anything, proper implementation is key, and any of these interfaces can suck with poor implementation.

 

Right now, if I was looking for a computer audio solution, and ready to purchase a DAC, my first choice would be to look for a USB DAC I liked with a really good internal USB interface, as there are now quite a few of these to choose from, including relatively affordable ones. The only Ethernet DACs I have heard which are really good are the Linn Klimax ($$$$), but I suspect there will be more good choices in Ethernet DACs soon. Certainly, for those who already own an SPDIF DAC which they love, a really good USB-SPDIF converter like the Hydra, or a really good Ethernet-SPDIF converter like the Sonore Rendu are great options. Ethernet is probably the better option for those who are not scared of network configuration, and do not care to spend a lot of time optimizing a computer or music server for high performance USB output. USB is probably the better option for those who want to use a local computer/server and like to tweak with things like music player software choices, power supplies, USB cables, USB output cards, etc.


ROON: DSD 256-Sonore opticalModule-Signature Rendu optical--Buffalo PRO or DSC-2--Ncore 400 Stereo-Focus Audio FS888-JL E-112 sub-Nordost Tyr USB, DIY AC cables, Iconoclast XLR, Iconoclast speaker, cables, Synergistic Orange & Hi Fi Tuning Supreme Cu Fuses, Dark Matter system clarifiers.    Design/Build Consultant with Sonore

 

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For example Mytek DAC seems to perform about as well with USB as it does with good S/PDIF or AES sources, thanks to JetPLL of the Dice chip.

 

 

Mytek sounds significantly better with a good SPDIF transport compared to USB. JetPPL sounds good on paper, but less good in action.


http://www.premiermixing.com

 

SqueezeBox Touch / MacBook Pro -> Audirvana Plus -> Firewire -> Mytek Stereo192-DSD -> GAC1 Pro -> Luxman L-410 -> Rubicon RP63F

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USB internal to a DAC, properly implemented is essentially perfect

Ethernet, internal to a DAC, properly implemented can also be essentially perfect

FireWire, internal to a DAC, properly implemented can also be essentially perfect

 

An external USB-SPDIF can be essentially perfect as well, but only with a very sophisticated, fully asynchronous SPDIF receiver in the DAC, there are only a very few DACs which incorporate this technology.

 

You don't need "fully asynchronous S/PDIF receiver", you just need a high quality DPLL. And not necessarily even that, for example my CS8416 + CS4398 combo is not asynchronous and still it gives very good performance with M2Tech hiFace connected to an ARM board. Since it's my own hardware I have a mux on the I2S and can switch the input to asynchronous USB implementations too for comparison.

 

I also systematically compare S/PDIF and AES inputs of other DACs (using hiFace and V-Link192) to their own async USB inputs. You can also check through all the HiFi-News DAC measurements, they do the same.

 

So "S/PDIF DAC when used with properly implemented S/PDIF transmitter can be essentially perfect".

 

And as in real life, you'll gonna have hard time finding anything perfect anywhere, especially if you want to find "perfect" USB implementation and "perfect" DAC in the same box... So you may end up getting better performance out of "perfect" DAC using S/PDIF.

 

And who said the S/PDIF or AES would be USB-based?

 

You can also asynchronously clock for example Mytek and Lynx AES16e or RME HDSPe AES. Mytek as clock master and Lynx/RME as slave. And Lynx or RME are cheaper than many audiophile interfaces.


Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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"You don't need "fully asynchronous S/PDIF receiver", you just need a high quality DPLL. And not necessarily even that, for example my CS8416 + CS4398 combo is not asynchronous and still it gives very good performance with M2Tech hiFace connected to an ARM board. Since it's my own hardware I have a mux on the I2S and can switch the input to asynchronous USB implementations too for comparison."

 

Well, lets just agree to disagree on this. I prefer to not have any PLLs, and just have the I2S data stream clocked by a fixed frequency oscillator of very low phase noise.

 

"So "S/PDIF DAC when used with properly implemented S/PDIF transmitter can be essentially perfect".

 

And as in real life, you'll gonna have hard time finding anything perfect anywhere, especially if you want to find "perfect" USB implementation and "perfect" DAC in the same box... So you may end up getting better performance out of "perfect" DAC using S/PDIF."

 

And, hence the use of words like "essentially", "virtually", and putting things in quotes.

 

"And who said the S/PDIF or AES would be USB-based?"

 

Not sure what this refers to, but the title of the thread is best USB-SPDIF converter, right?


ROON: DSD 256-Sonore opticalModule-Signature Rendu optical--Buffalo PRO or DSC-2--Ncore 400 Stereo-Focus Audio FS888-JL E-112 sub-Nordost Tyr USB, DIY AC cables, Iconoclast XLR, Iconoclast speaker, cables, Synergistic Orange & Hi Fi Tuning Supreme Cu Fuses, Dark Matter system clarifiers.    Design/Build Consultant with Sonore

 

                                                                                                  SONORE computer audio

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Well, lets just agree to disagree on this. I prefer to not have any PLLs, and just have the I2S data stream clocked by a fixed frequency oscillator of very low phase noise.

 

That's the ideal situation, but what comes out of the DAC is what determines the performance. Things are not that black and white in real world.

 

Not sure what this refers to, but the title of the thread is best USB-SPDIF converter, right?

 

Yes, that's about the source side. But you are trying to generalize that S/PDIF would be somehow systematically bad at the DAC side. But you don't really know which one is better until you evaluate. There's no correct generalized answer.

 

Again, looking at HFN results, just two examples.

 

Benchmark HGC2:

S/PDIF jitter 11 ps

USB jitter 28 ps

 

Chord QuteHD:

S/PDIF jitter 10 ps

USB jitter 136 ps


Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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hahaha:

 

"Benchmark HGC2:

S/PDIF jitter 11 ps

USB jitter 28 ps"

 

I am not familiar with Benchmark's most recent DACs, but previously they have always relied on horrible sounding hardware ASRCs to "filter jitter". I would never want to listen to this for pleasure. I am sure if you (miska) wanted to listen to an ASRC you could do it way better in software...

 

"Chord QuteHD:

S/PDIF jitter 10 ps

USB jitter 136 ps"

 

I asked previously if Chord's Qute uses their asynchronous SPDIF re-clocker, no one answered me. If Paul Miller's approach was actually capable of measuring jitter levels below ~150pS I would expect that to be the case from the 10pS number there, but he is not, and this is not an accurate measurement. It may be 10pS, but it just as easily could be 150. Miller Jitter analyzer is not capable of measuring down this low.


ROON: DSD 256-Sonore opticalModule-Signature Rendu optical--Buffalo PRO or DSC-2--Ncore 400 Stereo-Focus Audio FS888-JL E-112 sub-Nordost Tyr USB, DIY AC cables, Iconoclast XLR, Iconoclast speaker, cables, Synergistic Orange & Hi Fi Tuning Supreme Cu Fuses, Dark Matter system clarifiers.    Design/Build Consultant with Sonore

 

                                                                                                  SONORE computer audio

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Barrows. Chord's Qute doesn't use a buffer. I assume that's what you mean by async SPDIF.


Eloise

---

...in my opinion / experience...

While I agree "Everything may matter" working out what actually affects the sound is a trickier thing.

And I agree "Trust your ears" but equally don't allow them to fool you - trust them with a bit of skepticism.

keep your mind open... But mind your brain doesn't fall out.

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hahaha

 

I could continue the list...

 

If Paul Miller's approach was actually capable of measuring jitter levels below ~150pS I would expect that to be the case from the 10pS number there, but he is not, and this is not an accurate measurement. It may be 10pS, but it just as easily could be 150. Miller Jitter analyzer is not capable of measuring down this low.

 

I don't know what is exact resolution of his ADC, but the Jtest signal for these measurements is 48k 24-bit which in itself is technically capable of 1.2 ps.

 

(in SI system second as unit of time is lower case "s", capital "S" is Siemens for electrical conductance, I also get annoyed when someone uses "K" (Kelvin, unit of temperature) when talking about 103 kilo-prefix)

 

I asked previously if Chord's Qute uses their asynchronous SPDIF re-clocker

 

I've got impression that they have DPLL implemented in FPGA.

 

I also have variant of my DAC with dual-frequency oscillator with single frequency crystal inside combined with DPLL which improves it's jitter to 0.62 ps phase jitter (-150 dBc) with better thermal stability while being non-ovenized.


Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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hahaha:

 

"Benchmark HGC2:

S/PDIF jitter 11 ps

USB jitter 28 ps"


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I also have variant of my DAC with dual-frequency oscillator with single frequency crystal inside combined with DPLL which improves it's jitter to 0.62 ps phase jitter (-150 dBc) with better thermal stability while being non-ovenized.

 

Throwing up numbers, like "x pSec of jitter" and "-xxx dBc", without the context of carrier frequency and frequency offset are useless.

 

Just like a lot of this thread. There, I said it. Deal with it.

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Throwing up numbers, like "x pSec of jitter" and "-xxx dBc", without the context of carrier frequency and frequency offset are useless.

 

Btw, I didn't say it has anything to do with real performance of the DAC. Clock specs or type of the clock are pretty useless due to really loose relationship with real performance of the analog output. Only point here was DSP-based PLL can improve crystal clock stability and performance.

 

As we can see from various examples of S/PDIF PLL vs "high precision crystal oscillator driving asynchronous USB" where the S/PDIF PLL ends up performing better in the final output... (and counter examples)


Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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Btw, I didn't say it has anything to do with real performance of the DAC. Clock specs or type of the clock are pretty useless due to really loose relationship with real performance of the analog output. Only point here was DSP-based PLL can improve crystal clock stability and performance.

 

Say what?

 

1.) There is no PLL in a USB system. So, you are wrong. The crystal has direct effect on the output. Unless you stick in a ASRC. But since there is no need for one...........

2.) I don't care what kind of PLL it is, you are not going to get as good as a first-rate crystal. You can get good, but that is about as close as you will get.

3.) Trying to use SPDIF as an example of how USB can perform is a pretty weak argument.

 

Maybe you should measure some PLLs and really good clocks, before you post anything else that will embarrass yourself.

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for example my CS8416 + CS4398 combo is not asynchronous and still it gives very good performance

 

Really? Cirrus themselves published the results for this combo driven from an essentially "perfect" transmitter and I would not consider the results very good.

 

So "S/PDIF DAC when used with properly implemented S/PDIF transmitter can be essentially perfect".

 

Not if a CS841X is involved (Or an AKM or TI Receiver/Transceiver is involved) and aperfect SPDIF source (say nothing about real ones) is involved:

 

http://www.cirrus.com/en/pubs/appNote/AN339REV1.pdf


Magnum innominandum, signa stellarum nigrarum

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Only if you are silly enough to use crap like this:

 

http://www.ti.com/lit/ds/sbas142a/sbas142a.pdf

 

It is also "NRND". IOW, don't design with one.

 

No, I'm not talking about old USB interfaces, I'm talking about the little PHY transceivers which go before even the new processors (though now the XMOS U-series even has the PHY built in). Typical items like http://www.smsc.com/Downloads/SMSC/Downloads_Public/Data_Briefs/3320db.pdf

 

PLLs are really hard to get away from. Though maybe those in the PHYs are not relevant.

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Really? Cirrus themselves published the results for this combo driven from an essentially "perfect" transmitter and I would not consider the results very good.

 

I use it mostly at DSD128 in Direct DSD mode, but when I'm running PCM it is fixed at 192k from a hiFace and measure THD+N below -110 dB. And that THD is from the last analog output buffer stage. From intermediate differential stage output from AD797's it's closer to -120 dB. My J-test spectrum plots go only down to -150 dB and are completely clean. At least looks better than the HFN plots for dCS Vivaldi with USB, which is enough for me. :)

 

OK, not fair maybe because mine ended up with BOM cost around 2k€.

 

 

Pretty good results compared to many USB DACs, although I get better than them.


Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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1.) There is no PLL in a USB system. So, you are wrong. The crystal has direct effect on the output. Unless you stick in a ASRC. But since there is no need for one...........

 

Depends what kind of clock do you use. So far I've got best results from crystal driven DSP-based clock synthesizer.

 

2.) I don't care what kind of PLL it is, you are not going to get as good as a first-rate crystal. You can get good, but that is about as close as you will get.

 

You can improve the crystal performance with DSP clock synth.

 

3.) Trying to use SPDIF as an example of how USB can perform is a pretty weak argument.

 

My only argument is comparing real world performance of wide variety DACs sourced from high quality S/PDIF source versus built-in USB interface.

 

Maybe you should measure some PLLs and really good clocks, before you post anything else that will embarrass yourself.

 

Best clocks are DSP synthesized. ;)


Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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For example traditional PLL like CS8416 has cut-off frequency at 10 kHz and slowly rolls off, so you need a good quality source for these. However, with DSP PLL you can have a brick-wall cut-off at 10 Hz.

 

The biggest trick is to make it recursively "dial-in" at clock change to achieve reasonably fast lock time. But overall, it is better to keep everything running at fixed rate (like I do) and then there's no issue with lock times anyway.


Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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