Berkeley Alpha USB still relevant?

[mansr]

4 hours ago, firedog said:

Well, the iFi people basically implied he doesn't know how to use his measuring equipment properly. See their reaction to his measurements of their little PS. 

The iFi people are basically arrogant jerks that throw insults at anyone who dares criticise their products. They even had a post by Archimago taken down on bogus copyright claims.

[firedog]

35 minutes ago, mansr said:

The iFi people are basically arrogant jerks that throw insults at anyone who dares criticise their products. They even had a post by Archimago taken down on bogus copyright claims.

Whether they are arrogant or not (and I agree they sometimes are) has little to do with the validity of what they wrote about the proper way to use the Audio Precision device. Neither does the reaction to a post by Archimago. 

[plissken]

5 hours ago, firedog said:

Well, the iFi people basically implied he doesn't know how to use his measuring equipment properly. See their reaction to his measurements of their little PS. 

 

Amir already debunked that one. iFi doesn't know what they are talking about. 

[mansr]

32 minutes ago, firedog said:

Whether they are arrogant or not (and I agree they sometimes are) has little to do with the validity of what they wrote about the proper way to use the Audio Precision device. Neither does the reaction to a post by Archimago. 

Their history of dealing with criticism means I simply don't trust that they are being truthful when accusing Amir of misusing the equipment. Maybe he is, but I'd like to hear that from someone else with experience using it.

[plissken]

Just now, mansr said:

Their history of dealing with criticism means I simply don't trust that they are being truthful when accusing Amir of misusing the equipment. Maybe he is, but I'd like to hear that from someone else with experience using it.

 

This one has already been resolved. Amir answered them and showed iFi has no clue how to use the Audio Precision or properly setup it up in R&D mode. 

[R1200CL]

@amir57bs

Have you measure the SR7 and where can i find your findings ?

 

[Blake]

37 minutes ago, R1200CL said:

@amir57bs

Have you measure the SR7 and where can i find your findings ?

 

 

I don't believe amir57bs is the same person as Amir from audio science review.  

[R1200CL]

1 hour ago, Blake said:

 

I don't believe amir57bs is the same person as Amir from audio science review.  

 

OK. He’s probably banned from CA ?

[barrows]

On 1/11/2017 at 3:54 PM, shaq said:

Is the Berkeley Alpha USB / Asynchronous USB to SPDIF and AES Converter still relevant for newer DACs such as the new Ayre QX5-Twenty?

 

Or are they unnecessary?

Yes, it is irrelevant for that DAC.  The QX-5 already has a very, very, very good USB interface.

[amir57bs]

On 7/6/2018 at 2:17 AM, R1200CL said:

 

OK. He’s probably banned from CA ?

No I am here ?

 

amir57bs is not the same Amir

[KingRex]

Thank you Barrows.  This thread has to be one of the worst as it fell so far off track.   Much would be better as a private chat.

 

Per the subject.  I personally find the "SOURCE " to be ever important.  Even an operating system can affect sound.  Imagine the differences between laptops.  As in brand and age.   We have not even touched on software or outputting devices from the laptop. I keep mentioning laptop as in the beginning of this thread people were talking of laptops connected to a DAC and the Berkley  Alpha providing a benefit.   I doubt the maker of my server, Innuos or Antipodes would suggest putting a Alpha USB between their device and the DAC.  Computer audio is so system dependant.

 

Even in the most simple of topology, I find digital gear to be incredibly sensitive.  Take for instance the power supply.  I don't mean the Paul H this or that,  I mean the wall power, receptacle, cord from the wall. Amazes me the extent of change when altering these devices.  

 

The DAC is also all important.  My DAC, the new Mojo Mystique v3 is upgraded almost every year.  2 years is a long time in digital audio.  The last 5 years have been transformative in digital audio.   The thought of measuring anything that isn't the most current of the crop is meaningless.

 

IMO measurement are meaningless next to system design and hardware implemented.  Read that again before responding.  What is the source.  What was the source designed to output best.  What is the connected DAC. What was it designed to input best.  Is it possible a Alpha USB might benefit my chain.  Maybe,  but if I sent my server back for an upgrade and had a JCat FEMTO USB card with dedicated power supply installed, the Alpha would be redundant and possibly negatively impact sound.  Again, its all system dependant on what works and does not.  Before you get all hung up on measurements, make sure what you are looking to purchase is correct for your system.  There may be another route to get to the same sonic bliss.   Once you pick a route, if multiple products are offered, maybe then a look at measurements may be warranted.  

 

Do your homework and try to get your head around what computer audio is all about.  Its hard because there are so many moving parts.  I have followed recommendations from mentors, as well as talking to manufacturer and following their advise on implementing their gear.   You have to listen with open years.  If you stream and they tell you the upgraded ethernet card option improves streaming, well then, get the card or think of an external audiophile ethernet  switch.  They just told you something is there.  You have choices to make. 

Rex

[barrows]

@KingRex, Hmmm, not sure where to begin-is the "you" in the above referring to me?  I certainly have my head around computer audio as a design consultant for one of the most innovative companies in the field, and someone who has been in the industry, and an early adopter of computer as source fro the very early days, before even Amarra was on the scene.

Certainly, the source matters, as: "everything matters"!  But, I draw a line at folks whose "belief systems" appear to suggest that measurements do not matter.  As a part of a product design team, I can assure that measurements are critical to validate engineering approaches, while they are not everything, anyone who eschews measurements and only pays attention to subjective results in designing equipment is a fool.

As for the the topic at hand, I was speaking directly to the Ayre QX-5 DAC.  it has a USB interface which is independently powered, and totally isolated by optical isolation internally, where the master clock(s) are isolated from the USB receiver, totally, and the I2S data is re-clocked directly before its input to the digital processing portion of the DAC.  From a technical perspective, this is as low jitter and low noise a set up as is currently possible in digital audio, and the results can be both measured and heard.

So, specifically, with this DAC, there will be no advantage to a USB-SPDIF converter, whether Alpha USB, or something else like the Sonore ultraDigital.  In fact, the extra connections and power supplies may add enough complexity to the system to actually reduce performance.  Now as far as the source where that USB feed comes from, indeed I certainly agree that still the USB source will matter, and from my perspective, the best possible USB source would be the Sonore Signature Rendu SE.  I know why this so both from the technical, and subjective perspectives, as I listen to one every day here.

[Summit]

On 7/6/2018 at 1:49 AM, barrows said:

Yes, it is irrelevant for that DAC.  The QX-5 already has a very, very, very good USB interface.

 

Have you compared Ayre QX5-Twenty with and without the Berkeley Alpha USB?

[KingRex]

Barrows, I was not referring to you, and thank you for your support.  I may not have mentioned the DAC as having the isolation but it supports my point.  You have to look at the whole chain.  If the Ayre is isolating and reclocking, inserting the Alpha USB before the Ayre is redundant and may cause a perceived reduction in quality of playback.

 

However Barrows, you seem to have not reread my sentence.  I believe measurements are important, but 3 pages of people pissing over what or how someone is measuring seems a waste if your trying to measure a device you should not even be utilizing.  That was my point over measurements.  If you have a chain with no isolation and reclocking of the USB and a device such as the Berkeley may help, then by all means, use measurements as one  way to ensure you are getting the  quality of performance you are seeking.   

 

I personally do not have isolated USB on the output of my server. I did not opt for the option when I bought it as I was using spdif at the time. I now use USB and am told by the manufacturer I should get the JCat Femto USB card with independant PS installed.  That is an option.  I could probably get a Berkeley and achieve the same ends.  Measurements may be useful to know which device has higher performance standards.  Then again, I could do nothing.  The question for me is,  how much bang for the buck do I get.  I could also opt for a low Watt motherboard.  I could also opt for a new case with 5 wholly independant PS in the case, inches from the devices they power as opposed to 1 large external PS located 30" from the case with internal regulators in the unit.  It's all choices.  In my case the manufacturer seems to be doing a very good job of integrating the parts necessary for the topology I am utilizing.  Believing I can cobble together a pile of miscellaneous parts from random manufacturer is probably a less desirable route.  

[barrows]

@KingRex, no worries.  My comments refer specifically to the topic the OP posted: is a USB-SPDIF converter irrelevant with the Ayre QX-5.  I was not commenting in general on other component pairings.

 

@Summit, no, there is no need to hear the difference in this case, as what we are talking about here are technical issues which are very well understood and not "magical" in nature.  I have a very good technical understanding of how the USB interface in the QX-5 is implemented, and as such, there will not be an advantage to inserting another component to convert to SPDIF.

[Qhwoeprktiyns]

@barrows

Could you elaborate as to why you think, from a technical perspective, that the ayre usb implementation is particularly good? 

Thanks

[rodrigaj]

@barrows 

I found your explanation of the USB interface in the Ayre QX-5 DAC interesting.

 

I wonder if you would have similar insights into the PS Audio Direct Stream DAC USB interface implementation? And specifically, from an engineering standpoint, would there be any advantage to using a Sonore ultraDigital / ultraRendu combination for the purpose of getting away from the USB interface?

 

FWIW, I already have a BridgeII but prefer the ultraRendu USB interface because of the added SonicOrbiter OS flexibility.

 

 

[barrows]

4 minutes ago, hopkins said:

@barrows

Could you elaborate as to why you think, from a technical perspective, that the ayre usb implementation is particularly good? 

Thanks

Ayre does the following:  

 

1. The USB receiver circuit is powered by an independent, isolated power supply.

2. The USB receiver circuit is isolated from the rest of the DAC by optocouplers.

3. The masterclock(s) are located on the "clean" side of the isolation, close to the input of the DAC/processing stage.

4. 1 & 2 above insure the DAC and analog stage are isolated from noise produced both by the source component (USB feed) 

     and from the USB processor itself.

5. The digital feed to the DAC/processing stage is re-clocked, directly by the masterclock, right before the dAC/processing 

    stage.

 

This approach provides the highest degree of noise isolation from both the USB feed, and the USB processor itself, while keeping the masterclock(s) performing at their best (by having them on the "clean" side of the isolation).  By Re-clocking the data stream (I2S) directly before input to the DSC/processing stage, the jitter, where it matters, is essentially at the level of the masterclock.  In addition, the QX-5 uses custom masterclocks with very low phase noise.

[Qhwoeprktiyns]

Thanks. Point 5 is still an area where a lot of progress could be made... Not speaking specifically of the Ayre, but of all DACs... 

[barrows]

7 minutes ago, rodrigaj said:

@barrows 

I found your explanation of the USB interface in the Ayre QX-5 DAC interesting.

 

I wonder if you would have similar insights into the PS Audio Direct Stream DAC USB interface implementation? And specifically, from an engineering standpoint, would there be any advantage to using a Sonore ultraDigital / ultraRendu combination for the purpose of getting away from the USB interface?

 

FWIW, I already have a BridgeII but prefer the ultraRendu USB interface because of the added SonicOrbiter OS flexibility.

 

 

First of all, I am not at all surprised that you prefer the ultraRendu with the DS vs. the Bridge 2.  Sonore's VP uses the DS DAC (with some mods), and much prefers the performance using the Signature Rendu SE vs. the Bridge 2.

 

As to the DS USB interface, it is not isolated in the same way as Ayre's, one can check this easily with a multi meter, and one finds that USB ground is continuous with the output signal ground.  But, I do believe that in the DS the FPGA does re-clock the data stream for all inputs, from the (pretty good) masterclock in the DAC.  Note, that with the non-isolated USB inputs on many DACs, a really good USB source like the Rendus will provide an even bigger advantage in sound quality due to their very clean USB output.  I was certainly impressed with the sound of the DS DAC via USB (from a Rendu of course) when I had it here.

 

I have no experience with using the ultraDigital with the DS DAC, and there are too many variables to speculate on whether that might be better (or worse) than just using the USB input direct from a Rendu.  I do know that the Sonore VP uses the USB input on his DS, direct from a Signature Rendu SE, and he is a very discerning audiophile with an excellent system (Raidho speakers, Pass Labs X-250.8) and he loves the sound quality he is getting.  I have only listened to the DS DAC myself through the USB input.  My personal preference when in doubt, is to keep it simple and not add more conversions, and boxes, and power supplies to the system, as every additional component is just another noise source at the very least.

 

I know that there is an apparent negative association with USB audio, but I feel this is not warranted at all.  USB audio can be excellent, it is just another input, and as long as one pays attention to the details, it provides excellent performance.  Every input type has its pluses and minuses.  I generally prefer USB as long as one has a really good USB source (Rendu of course!) as it allows for asynchronous clocking where the DAC clock is the master, as it should be, and additionally USB usually allows for the greatest range in terms of sample rates, and I like to oversample in software.

[barrows]

5 minutes ago, hopkins said:

Thanks. Point 5 is still an area where a lot of progress could be made... Not speaking specifically of the Ayre, but of all DACs... 

I am curious, what makes you think this?  Or are suggesting that not all DACs actually do this?

 

With async USB input it is rather simple to re-clock the data stream directly before the DAC/processing stage via  a flip-flop adjacent to the DAC (chip or whatever) input. 

[mansr]

36 minutes ago, barrows said:

Ayre does the following:  

 

1. The USB receiver circuit is powered by an independent, isolated power supply.

2. The USB receiver circuit is isolated from the rest of the DAC by optocouplers.

3. The masterclock(s) are located on the "clean" side of the isolation, close to the input of the DAC/processing stage.

4. 1 & 2 above insure the DAC and analog stage are isolated from noise produced both by the source component (USB feed) and from the USB processor itself.

That's a pretty obvious way to design things, if you ask me. The isolation devices should only add a few dollars to the BOM.

 

36 minutes ago, barrows said:

5. The digital feed to the DAC/processing stage is re-clocked, directly by the masterclock, right before the dAC/processing stage.

This may not even be necessary. For many DAC chips, only the master clock matters for performance. The bit and word (LR) clocks typically need to be synchronised to the master clock, but no particular phase relationship is required. The first thing that happens to the I2S input is deserialising and deinterleaving, and after that the bit/word clock signals are no longer used. One could say the data is "reclocked" by the input stage of the chip.

[barrows]

6 minutes ago, mansr said:

This may not even be necessary. For many DAC chips, only the master clock matters for performance. The bit and word (LR) clocks typically need to be synchronised to the master clock, but no particular phase relationship is required. The first thing that happens to the I2S input is deserialising and deinterleaving, and after that the bit/word clock signals are no longer used. One could say the data is "reclocked" by the input stage of the chip.

While I agree in a sense, for instance with an ESS chip running in its (normal) asynchronous mode with its internal DPLL active, this is not the case for the same chip(s) if one wants to run them in the synchronous mode.  Here I use DIY DACs with ESS 9018 and 9038 chips, and in every case, synchronous mode sounds better, and to run this mode requires that the data lines be phase aligned directly by the masterclock for low jitter performance.  Same is true, for example, if using one of the newer AKM chips via its direct DSD mode, and for chinless DAC approaches like the DSC-1 style DSD DAC (versions of which exist in Denafrips, T+A, and Holo Audio DACs).

So yes, if one is OK with running an ESS chip in async mode then one can get away with it, but in my experience this is not the best path to good sound quality.  Since the example was the Ayre QX-5, Ayre also runs the ESS 9038 in the QX-5 in sync mode, so they have to re-clock.

Additionally, the isolation chips add somewhere around 200 pS of jitter, by re-clocking directly before the conversion stage this jitter is eliminated.

[Qhwoeprktiyns]

44 minutes ago, barrows said:

I am curious, what makes you think this?  Or are suggesting that not all DACs actually do this?

 

With async USB input it is rather simple to re-clock the data stream directly before the DAC/processing stage via  a flip-flop adjacent to the DAC (chip or whatever) input. 

 

Sure, I did not mean the fact that the data stream is re-clocked, but the "secondary" effect that this clocking may have itself on the noise coming into the DAC. I am not an expert ! This is just what I understand from reading and discussion with some DAC designers.

[barrows]

1 minute ago, hopkins said:

 

Sure, I did not mean the fact that the data stream is re-clocked, but the "secondary" effect that this clocking may have itself on the noise coming into the DAC. I am not an expert ! This is just what I understand from reading and discussion with some DAC designers.

What is this "secondary" effect, what is the noise source?