XMOS XU208 USB BRIDGES - THE LATEST GEN HAS ARRIVED!

[rb2013]

  Well I trust you ear but I guess I am gonna keep it "simple" for a while. Until I figure the next best move... I would like to add a dc jack and a switch between external and usb power, and buy a fancy psu perhaps. And I will add for sure an i2s out.
 
You sure were right about this interface, though. Thanks.

De Nada
 
I made some other tweeks with my PC Ethernet to the REDNET that have yielded some nice SQ benefits.
 
This Antelope Ovenized OXCO Isochrone OCX clock will be here on Wed to reclock the RN3 - it also allows an 10Mhz Rubidium Atomic clock input - as does the Mutec MC-3+ USB.

 
 
 
So I'm looking for one of these used:
 
http://www.thinksrs.com/products/PERF10.htm
 
Stanford Research uses a special cross cut crystal to achieve the most remarkable phase noise numbers - especially for an atomic clock:

Accuracy at shipment	±0.05 ppb ( ±5 × 10-11)
Aging (after 30 days)	<5 × 10-11 (monthly) <5 × 10-10 (yearly) 5 × 10-9 (20 years, typ.)
Spurious harmonics	<-60 dBc
Phase noise (SSB)	<-130 dBc/Hz (10 Hz) <-140 dBc/Hz (100 Hz) <-150 dBc/Hz (1 kHz) <-155 dBc/Hz (10 kHz)
Short term stability      (Allan variance)	<2 × 10-11 (1 s) <1 × 10-11 (10 s) <2 × 10-12 (100 s)
Warm-up time	<6 minutes (time to lock)

[td=colspan:2] Rubidium Oscillator [/td]

 
Looking at this new Cary tubed DAC that has a Wclock input.
http://www.audiostream.com/content/cary-audio-dac-200ts#tMxDe2uXd57doS4R.97
So then the RN3, Mutec (as SPDIF reclocker) and the DAC would all be run on this ultra precise, ultra low phase noise Rubidium clock.
 
This setup just could be the sota in computer audio today.

 

[FredA]

 
De Nada
 
I made some other tweeks with my PC Ethernet to the REDNET that have yielded some nice SQ benefits.
 
This Antelope Ovenized OXCO Isochrone OCX clock will be here on Wed to reclock the RN3 - it also allows an 10Mhz Rubidium Atomic clock input - as does the Mutec MC-3+ USB.

 
 
 
So I'm looking for one of these used:
 
http://www.thinksrs.com/products/PERF10.htm
 
Stanford Research uses a special cross cut crystal to achieve the most remarkable phase noise numbers - especially for an atomic clock:

Accuracy at shipment	±0.05 ppb ( ±5 × 10-11)
Aging (after 30 days)	<5 × 10-11 (monthly) <5 × 10-10 (yearly) 5 × 10-9 (20 years, typ.)
Spurious harmonics	<-60 dBc
Phase noise (SSB)	<-130 dBc/Hz (10 Hz) <-140 dBc/Hz (100 Hz) <-150 dBc/Hz (1 kHz) <-155 dBc/Hz (10 kHz)
Short term stability      (Allan variance)	<2 × 10-11 (1 s) <1 × 10-11 (10 s) <2 × 10-12 (100 s)
Warm-up time	<6 minutes (time to lock)

[td=colspan:2] Rubidium Oscillator [/td]

 
Looking at this new Cary tubed DAC that has a Wclock input.
http://www.audiostream.com/content/cary-audio-dac-200ts#tMxDe2uXd57doS4R.97
So then the RN3, Mutec (as SPDIF reclocker) and the DAC would all be run on this ultra precise, ultra low phase noise Rubidium clock.
 
This setup just could be the sota in computer audio today.

At some point improving the clock must not make such a difference, depending on the SPDIF receiver used by a DAC. But again, if your ear tells you it's better, there must be a reason.
 
Some SPIDIF receivers are less tolerant to phase noise than others. I have both the WM8805 and the DIR9001 on my dac. I tried both with the F-1. The sound is so similar i am not sure i could tell the difference in a blind test. I think they both do reclocking and both work better with a better signal at the input (expected). The DIR9001 works better with low quality signals(jittery) however and then I can easily hear the difference between the two.

 

[rb2013]

  At some point improving the clock must not make such a difference, depending on the SPDIF receiver used by a DAC. But again, if your ear tells you it's better, there must be a reason.
 
Some SPIDIF receivers are less tolerant to phase noise than others. I have both the WM8805 and the DIR9001 on my dac. I tried both with the F-1. The sound is so similar i am not sure i could tell the difference in a blind test. I think they both do reclocking and both work better with a better signal at the input (expected). The DIR9001 works better with low quality signals(jittery) however and then I can easily hear the difference between the two.

I used not be much of a believer in power supplies and AC noise filtering and isolation.  But after playing around with different LPS's, SMPS's, and AC filter gear - boy have I changed my mind.  What mattered for analog is not the same as for digital - esp computer audio.
 
Really at the heart of the digital process - is the clocking.  And clocks have really advanced in the last few years - but these femto clocks are so sensitive to dirty power.  Whether from the power grid or the noise that audio gear PS's dump back into the local power system.  SMPS's are the worst! 
 
Anyway I'll know more on Wednesday - at least as far as the Antelople is concerned.
 
Here is a good review on the OCX:
http://www.the-ear.net/review-hardware/antelope-isochrone-ocx-master-clock-word-clock
 
On the SRS PERF10 Atomic Clock:
http://www.soundstageultra.com/index.php/equipment-menu/610-stanford-research-systems-perf10-rubidium-audio-clock#most-read-equipment-reviews

 

[FredA]

I used not be much of a believer in power supplies and AC noise filtering and isolation.  But after playing around with different LPS's, SMPS's, and AC filter gear - boy have I changed my mind.  What mattered for analog is not the same as for digital - esp computer audio.

Really at the heart of the digital process - is the clocking.  And clocks have really advanced in the last few years - but these femto clocks are so sensitive to dirty power.  Whether from the power grid or the noise that audio gear PS's dump back into the local power system.  SMPS's are the worst! 

Anyway I'll know more on Wednesday - at least as far as the Antelople is concerned.

Here is a good review on the OCX:
http://www.the-ear.net/review-hardware/antelope-isochrone-ocx-master-clock-word-clock

On the SRS PERF10 Atomic Clock:
http://www.soundstageultra.com/index.php/equipment-menu/610-stanford-research-systems-perf10-rubidium-audio-clock#most-read-equipment-reviews

I agree you will improve the sound by reducing amplitude and phase noise since they combine to produce the overall timing error. At some point, the error will become inaudible. I wonder if that point can be reached with an spdif receiver, which uses a pll and has its limitations. That is why i insist on using the i2s input on my dac because then the timing is 100% determined by the ddc and phase noise can in theory be lower than what any spdif receiver can produce. But the clock's integrity is tough to preserve hence my concern with cable length. Keeping the clock in synch with data might also be a problem.

An external clock fed from the ddc to the dac can also work as long as you are to able to preserve the clock signal and have proper synching with the data.

Someone will come up with an integrated solution to this problem someday.

 

[rb2013]

I agree you will improve the sound by reducing amplitude and phase noise since they combine to produce the overall timing error. At some point, the error will become inaudible. I wonder if that point can be reached with an spdif receiver, which uses a pll and has its limitations. That is why i insist on using the i2s input on my dac because then the timing is 100% determined by the ddc and phase noise can in theory be lower than what any spdif receiver can produce. But the clock's integrity is tough to preserve hence my concern with cable length. Keeping the clock in synch with data might also be a problem.

An external clock fed from the ddc to the dac can also work as long as you are to able to preserve the clock signal and have proper synching with the data.

Someone will come up with an integrated solution to this problem someday.

 
Well those are good points - you have to separate the clocking in the AOIP DDC from the reclocking of the SPDIF output signal sent to the DAC.
 
There are several issues, phase noise probably being the most important.
Here is a great white paper showing phase noise plots of a TXCO vs a OXCO:  A typical OXCO will have anywhere from 20dB to 40dB less phase noise at 10hz
http://www.greenrayindustries.com/library/PhaseNoise08.pdf
 
For the 24.576Mhz CCHD-957 shows -97dB at 10Hz.  The Vectron OX202 as an example at -115dB at 10 Hz.
 
Then there is the clock accuracy - again here OXCO's excel TXCO's by a significant margin:
Take the Crystek CCHD 957 for example: they vary from 20ppm to 50ppm
versus a typical OXCO, say the Vectron OX202 at 2.6ppm
 
Then there is drift in accuracy over time:
CCHD 957: 3ppm 1st yr , then 1ppm each year thereafter.
OX202: 0.2ppm 1st yr, then 2ppm after 20 Yrs!
 
So it's not just the initial accuracy - but the maintaining of that accuracy over time.  On all counts the SRS PERF10 is orders on magnitude better on all these measures:
PERF10:
Phase noise at 10 Hz: -130dB
Clock accuracy: .05ppb (that's ppb -parts per billion vs ppm - parts per million)
Clock drift: 5ppb yearly, 50ppb after 20 years.
 
So the question is  does an atomic clock (with ultra low phase noise - most have high phase noise) acting as a disciplining clock to the already ultra stable and low noise ovenized OXCO clock - improve the SQ?  I hope to find out one day soon.
 
One advantage to SPDIF is the clock - can be reclocked with a high quality external clock.  I found the W4S Remedy pretty good at this (it uses the Crystek CCHD clocking), but the Mutec MC-3+ USB is in another league.  So here you have the ultra clean 1G clock technology sending a cleaner clock signal then can likely be arrived at (using the CCHD, NDK or just plain TXCO clocks) with i2s.  A very high quality SPDIF coax cable is absolutely necessary in the connection.  An expensive path - but one that has really paid off in extremely high sound quality.
 
So the question would be - will the addition of disciplining SRS Rubidium clock to the Mutec clock enhance it's already excellent clocking?  Will that translate into better SQ?

 

[rb2013]

Good paper on SPDIF, DAC clocking and jitter:
http://www.audiocraftersguild.com/AandE/npt.on.jitter2.htm
 

4. Popular S/PDIF receiver chips like the Yamaha YM3623B and Crystal CS8412 are NOT crystal controlled but rather recover the necessary clock from internal Phase Locked Loops (PLL) locked onto the incoming data stream. The simple two pin can crystals often seen directly attached to '3623's and '8412's are optional. The 3623 uses the crystal clock to quickly lock onto the S/PDIF signal. The 8412 uses the crystal clock to determine and display the sample rate and jitter level of the S/PDIF signal. Both parts ignore the local crystal clock once locked onto the S/PDIF signal. 

5. Better (i.e. more expensive) outboard DACs use additional tighter PLLs after the receiver chip to further cleanup the clock. Generally there is a trade off between low jitter PLL and wide locking such that low jitter PLLs may result in a DAC being unable or slow to lock onto a high jitter S/PDIF input requiring use of a low jitter Class 1 source as defined in the 'Red Book' spec. from Sony/Philips. This lack of universality and the fact that parts budget spent on low jitter PLLs (like individual crystals for each sample rate) reduces the parts budget for everything else (like filters, DACs, analog circuits, power supplies, and case) leads many designers to leave well enough alone and use the clock straight out of the receiver chip investing the saved resources elsewhere in the design or lowering the cost. This allows the DACs master clock to be strictly a function of the source and interface. 

 

[FredA]

  Good paper on SPDIF, DAC clocking and jitter:
http://www.audiocraftersguild.com/AandE/npt.on.jitter2.htm
 

 
In answer to your previous post, not this one:
 
Interesting. I suppose there is still oscillators in those SPDIF receivers feeding the extracted clock, but they don't have to be so accurate because of an averaging effect.
 
I think I have the high-quality pll part in my dac. It could be worthwhile turning it back on if i keep on using the spdif input.

 

[FredA]

By the way iFi is about to release an spdif reclocker/purifier. No need for an extra cable, it plug in directly into the dac or ddc.

 

[FredA]

Well those are good points - you have to separate the clocking in the AOIP DDC from the reclocking of the SPDIF output signal sent to the DAC.

There are several issues, phase noise probably being the most important.
Here is a great white paper showing phase noise plots of a TXCO vs a OXCO:  A typical OXCO will have anywhere from 20dB to 40dB less phase noise at 10hz
http://www.greenrayindustries.com/library/PhaseNoise08.pdf

For the 24.576Mhz CCHD-957 shows -97dB at 10Hz.  The Vectron OX202 as an example at -115dB at 10 Hz.

Then there is the clock accuracy - again here OXCO's excel TXCO's by a significant margin:
Take the Crystek CCHD 957 for example: they vary from 20ppm to 50ppm
versus a typical OXCO, say the Vectron OX202 at 2.6ppm

Then there is drift in accuracy over time:
CCHD 957: 3ppm 1st yr , then 1ppm each year thereafter.
OX202: 0.2ppm 1st yr, then 2ppm after 20 Yrs!

So it's not just the initial accuracy - but the maintaining of that accuracy over time.  On all counts the SRS PERF10 is orders on magnitude better on all these measures:
PERF10:
Phase noise at 10 Hz: -130dB
Clock accuracy: .05ppb (that's ppb -parts per billion vs ppm - parts per million)
Clock drift: 5ppb yearly, 50ppb after 20 years.

So the question is  does an atomic clock (with ultra low phase noise - most have high phase noise) acting as a disciplining clock to the already ultra stable and low noise ovenized OXCO clock - improve the SQ?  I hope to find out one day soon.

One advantage to SPDIF is the clock - can be reclocked with a high quality external clock.  I found the W4S Remedy pretty good at this (it uses the Crystek CCHD clocking), but the Mutec MC-3+ USB is in another league.  So here you have the ultra clean 1G clock technology sending a cleaner clock signal then can likely be arrived at (using the CCHD, NDK or just plain TXCO clocks) with i2s.  A very high quality SPDIF coax cable is absolutely necessary in the connection.  An expensive path - but one that has really paid off in extremely high sound quality.

So the question would be - will the addition of disciplining SRS Rubidium clock to the Mutec clock enhance it's already excellent clocking?  Will that translate into better SQ?

Even better if connectd to the rednet it sounds so good that you can get rid of the mutec.

 

[FredA]

Glad to hear you are enjoying my little discovery...just another amazing audio device I blazed the trail on (despite the early ridicule from one industry insider about my enthusiasm for the F-1 - just check the Regen thread).:wink_face: :rolleyes:

Now you've only scratched the surface with what the F-1 is capable of - Here is the chain I'm running now in my office system:
 


[COLOR=000000]PC>PPA V2 USB card (TeraDak X1 - Nichicon HW caps)>Forza Twin Copper Split USB cable>Startech LEX>BJC CAT6 UTP 550Mhz>Startech REX (with one Jitterbug - Breeze 24VDC LPS+DC iPurifer)>LH Labs 2G split USB cable (data only leg)>W4S Recovery(TeraDak LPS DC-30W+Cerious Graphene PC+ DC iPurifier)>Curious 200mm USB Link>iPur 2>F-1>Audience AU24 SE Digital SPDIF RCA>APL DAC[/COLOR]

[COLOR=000000]Power link to Recovery - this multi-stage AC line filtering and isolation makes a big difference in sound purity:[/COLOR]
[COLOR=000000]PS Audio AC Recep>CPCC Hi Current Top Gun>Richard Gray RGCP400 PRo>Art Audio PB 4X4 Pro (3 dedicated ones - one for each part of the chain: F-1 Chain, DAC, PC to isolate ps noise from the other components)>Cerious Tech Graphene Red>TeraDak DC-30W>DC iPur>Recovery.[/COLOR]

[COLOR=000000]The addition of the ICRON/Startech GB LAN Iso audio USB extender is another major leap in SQ.  But the addition of the iPur2 right before the F-1 and the Recovery (for impedance matching - fed by a LPS), Curious 200MM link - all these add to better SQ.  Same goes for using a top quality SPDIF digital cable.[/COLOR]

[COLOR=000000]Also the Cerious Tech Graphene Extreme Red on the PS might give you a pretty significant step up in SQ as well (a few doubters on this cable - and well cables in general - have been blown away by this amazing cable).[/COLOR]

[COLOR=000000]Interesting that the SDPIF from your F-1 is bettering the i2s from the modded Breeze Audio.  As I have argued here with said audio industry insider numerous times, as OP dismisses SPDIF as pure garbage - and i2s the ONLY viable high SQ solution, that while i2s is better, it's the USB DDC(and it's USB data and power chains that really make the difference).[/COLOR]

[COLOR=000000]Here is my most recent ranking and ratings:[/COLOR]
[COLOR=000000]Here would be my current ratings and rankings (the numbers are just a relative number - they are not percentages).  The Breeze Audio (Talema) DU-U8 = 100[/COLOR]


[COLOR=000000] [/COLOR]


[COLOR=000000]Obviously these are my subjective ratings YMMV - and yes I have owned (had a loaner) all these for an extended period of time:[/COLOR]


 


REDNET 3/Cerious/Mutec 3+ USB/SR Element Copper digital cable                            253


[COLOR=000000]REDNET 3/Cerious/Mutec 3+ USB/Audience au24 se digital cable                              250[/COLOR]


[COLOR=000000]REDNET 3/Cerious/Mutec 3+ USB (SPDIF reclocker)                                                 240[/COLOR]


[COLOR=000000]REDNET 3/Cerious Power Cord                                                                               220[/COLOR]


[COLOR=000000]Singxer F-1 DC30W/Cerious/Recovery/DCiPur/ iPur2/Startech GB LAN Iso USB               170[/COLOR]


[COLOR=000000]Mutec 3+ Smart Clock USB/Cerious Power Cord                                                        155[/COLOR]


[COLOR=000000]Singxer F-1 DC30W/Cerious/Recovery/DCiPur/ iPur2                                                   145[/COLOR]


[COLOR=000000]PUC2 Lite TeraDak DC30W/Cerious/Regen                                                               135[/COLOR]


[COLOR=000000]Singxer F-1 DC30W/Cerious                                                                                   135[/COLOR]


[COLOR=000000]DXIO Silver/TeraDak DC-30W/Cerious                                                                      130[/COLOR]


[COLOR=000000]Singxer X-1 DC30W/Cerious/Recovery/DCiPur/iPur2                                                    125[/COLOR]


[COLOR=000000]PUC2 Lite - USB power                                                                                          110[/COLOR]


[COLOR=000000]Breeze/Cerious Graph/WBT RCA Nexgen                                                                   109[/COLOR]


[COLOR=000000]Breeze DU-U8 with Cerious Graphene                                                                      108[/COLOR]


[COLOR=000000]Breeze DU-U8 (Talema version)                                                                              100[/COLOR]


[COLOR=000000]Breeze DU-U8 (BingZi version)                                                                                 95[/COLOR]


[COLOR=000000]Hydra Z with LPS                                                                                                    92[/COLOR]


[COLOR=000000]Melodious MX-U8 (upgraded caps)                                                                             85[/COLOR]


[COLOR=000000]Melodious MX-U8 (stock)                                                                                          81[/COLOR]


[COLOR=000000]Gustard U12 (upgraded caps)                                                                                    76[/COLOR]


[COLOR=000000]Gustard U12 stock                                                                                                   72[/COLOR]


[COLOR=000000]iDAC DAC2 (used as a DDC)                                                                                      65[/COLOR]


[COLOR=000000]Musiland USB3.0 US Dragon                                                                                      65[/COLOR]


[COLOR=000000]M2Tech EVO with LPS                                                                                              60[/COLOR]


[COLOR=000000]Audiophileo 2  USB Power                                                                                         50[/COLOR]


[COLOR=000000]M2Tech Hiface                                                                                                         40[/COLOR]


[COLOR=000000] [/COLOR]


[COLOR=000000]Note the two major leaps - one by adding the ICRON/Startech GB LAN Iso Audio USB Extender into the chain.  Then the bigger leap away from USB completely to the REDNET3 Dante AES67 AOIP.  The Mutec 3+ did not help as an ext Word Clock to the RD3 - but after the RD3 as a SPDIF reclocker - excellent.[/COLOR]


 


[COLOR=000000]As I have rated (YMMV) the use of the ICRON/Startech makes a big difference.  But right now the REDNET AOIP is just in another league.[/COLOR]


 


[COLOR=000000]So you my have some further surprises in computer SQ coming down the road.[/COLOR] :wink_face:  

It would be interesting to hear the best f-1 setup reclocked by the mutec. Should be something.

 

[ldp216]

What are you impressions of the Pro3z ( http://www.head-fi.org/t/803111/xmos-xu208-usb-bridges-the-latest-gen-has-arrived/2910 )?

 

[ldp216]

 
I ordered one, it's on it's way, although I wish it had BNC. It apparently also comes with a battery enclosure to power it.
 
"Thank You for interesting in our product,
Free AA battery box is shipped with the package
The marking on the enclosure has indication of the socket polarity.
Technically, battery is the most silent power in the world.
Please notes the device may need upto 1A during startup."

What are you impressions of the Pro3z ( http://www.head-fi.org/t/803111/xmos-xu208-usb-bridges-the-latest-gen-has-arrived/2910 )?

 

[mourip]

 
 
So then the RN3, Mutec (as SPDIF reclocker) and the DAC would all be run on this ultra precise, ultra low phase noise Rubidium clock.
 
This setup just could be the sota in computer audio today.

 
So where does the Antelope get hooked up in this chain? As an external clock to the RN3? Would you still need the Mutec then? Would the Antelope be an external clock for both?
 
Sorry. A little fuzzy on the implementation

 

[rb2013]

   
In answer to your previous post, not this one:
 
Interesting. I suppose there is still oscillators in those SPDIF receivers feeding the extracted clock, but they don't have to be so accurate because of an averaging effect.
 
I think I have the high-quality pll part in my dac. It could be worthwhile turning it back on if i keep on using the spdif input.

They just initiate the clock locking then turn it over to the source clock.  In my case the Mutec MC-3 USB.  Hopefully further disciplined by the SRS PERF10 Rubidium.
 

  By the way iFi is about to release an spdif reclocker/purifier. No need for an extra cable, it plug in directly into the dac or ddc.

That will be interesting.  Will it accept a 10Mhz Rubidium disciplined Wclock feed?
 

Even better if connectd to the rednet it sounds so good that you can get rid of the mutec.

Well the Mutec is a pretty darn good SPDIF source clock - and will accept a 10Mhz atomic clock feed.

 

[rb2013]

   
So where does the Antelope get hooked up in this chain? As an external clock to the RN3? Would you still need the Mutec then? Would the Antelope be an external clock for both?
 
Sorry. A little fuzzy on the implementation

Yes the Antelope OXCO OCX will be the Wclock input (set as ext clock in the RN control), the Mutec the post RN SPDIF reclocker.
 
What's cool is both can accept the atomic SRS PERF10 discipline 10Mhz clock.  So a double kill shot.
 
Sorry folks this really is at the very cutting edge of computer audio...and relatively expensive.