USB audio cracked... finally!

[Doak]

2 hours ago, PeterSt said:

 

Hi - You can bet it is.

https://uk.lush.com

Haha... 

[austinpop]

48 minutes ago, PeterSt said:

If someone else is not faster :In a later post Anthony was even more explicit about this.  So, planned ...Not sure this is the best idea though (for that person).

 

Thank you, Peter.

 

On 7/14/2017 at 11:19 PM, acg said:

The Lush is around 200 euro depending on length.  At this stage I am unaware of anyone out of the Phasure group that has one but I intend to take mine down to the Gold Coast next time and have a play with it in a couple of excellent but completely different systems to mine.  One of them is the guy that makes the Curious Cables (he has a fantastic system) so it will be very interesting to hear The Lush in that system against that cable.

 

Awesome, I look forward to this comparison.

 

I need yet another USB cable about as much as a hole in my head! But - I am always interested, and keep an open mind.

 

In general, I do find I can hear cable differences, but they tend to - for me - be subtle, not transformative.

[Ralf11]

8 hours ago, Panelhead said:

...USB-/TB3...

 

yes, what about Thunderbolt as implemented via USB-C ?

 

any hope there as an interface?

[PeterSt]

2 minutes ago, austinpop said:

 

In general, I do find I can hear cable differences, but they tend to - for me - be subtle, not transformative.

 

Yes, I can 100% imagine this. But this really is another thing. Btw for the Clairixa counts the same.

Anthony should really ask the Curious guy how he actually comes to decisions about making a USB cable. I know mine and mine really use "properties" so to speak. But others ? ... what I learned is that it is so difficult to get what you what you want (by components) that possibly people travel the easiest path with a nice sleeve.

But of course I can't really know.

 

Thanks,

Peter

[austinpop]

39 minutes ago, PeterSt said:

Anthony should really ask the Curious guy how he actually comes to decisions about making a USB cable. I know mine and mine really use "properties" so to speak. But others ? ... what I learned is that it is so difficult to get what you what you want (by components) that possibly people travel the easiest path with a nice sleeve.

But of course I can't really know.

 

Well - to the extent that neither of you have really revealed how you make your cable, here is the Curious guy's "story:" http://www.curiouscables.com/our-story.html

 

Frankly, I could care less about the prose.

 

@acg - once you actually compare how they sound - which should be fun! - please report back.

[The Computer Audiophile]

8 pages and this thread should already be well off the rails. 

 

Thanks to everyone for being respectful and helping (or not participating at all) to make the discussion enjoyable. 

[Panelhead]

1 hour ago, Ralf11 said:

 

yes, what about Thunderbolt as implemented via USB-C ?

 

any hope there as an interface?

  Well Metric Halo is releasing models now. I expect the rest of the prosumer group is not far behind.

  I purchased a MB Pro this summer with only TB-3 buss. Waiting for hardware to catch up.

  Really like the Clarett 4Pre currently in the system. Normal Thunderbolt works well, but is already superseeded.

 

  

[BigAlMc]

3 hours ago, austinpop said:

Got it - be patient!

 

I have to be honest - I was unaware of the Phasure, um, universe, until @hols mentioned the Lush cable on another thread.

 

Would I be laughed off the thread if I asked if anyone could compare it to the Curious 0.2m link?

 

Hi Rajiv, 

 

Not exactly what you were asking for but I currently have a 1m Curious cable and this thread has prompted me to take the plunge and order 70cm Lush cable. 

 

So not the 20cm comparison you asked about and only my enthusiastic but perhaps unrefined ears. But Ill defo be comparing the Lush to the Curious. 

 

I'm also intrigued about the Lush / ISO Regen combo which I'll be trying out. 

 

Cheers, 

Alan 

[austinpop]

4 minutes ago, BigAlMc said:

 

Hi Rajiv, 

 

Not exactly what you were asking for but I currently have a 1m Curious cable and this thread has prompted me to take the plunge and order 70cm Lush cable. 

 

So not the 20cm comparison you asked about and only my enthusiastic but perhaps unrefined ears. But Ill defo be comparing the Lush to the Curious. 

 

I'm also intrigued about the Lush / ISO Regen combo which I'll be trying out. 

 

Cheers, 

Alan 

 

Perfect! Look forward to it.

[Ralf11]

11 hours ago, Panelhead said:

...USB-/TB3...

 

I mean does Thunderbolt as implemented via USB-C solve (or reduce) the problems in USB 2 as an interface?

 

 

[Panelhead]

1 hour ago, Ralf11 said:

 

I mean does Thunderbolt as implemented via USB-C solve (or reduce) the problems in USB 2 as an interface?

 

 

 I do not know that answer. I know FireWire with adapter into Thunderbolt buss is way better than straight FW. This was easy to check by simply moving the cable from port to another.  My music computer has both. 

  I expect time will tell if the newer transmission implementations will require as much hard work as USB. I sure hope not.

  USB is maybe there now. After many smart people have spent years improving the transmission. 

[pkane2001]

10 hours ago, Jud said:

 

Hi Paul.

 

@PeterSt believes this must have to do with current draw.  John Swenson, as Peter mentioned, believes it has to do with injecting noise onto the DAC’s ground plane because the USB receiver chip must work harder.  In either case, these effects would then in turn affect the DAC’s clock and/or the zero crossing point of the signal (determined by comparing signal to ground, the latter notionally being zero, but if there is noise on ground, it isn’t actually zero; you can read ESS white papers where much is made of noise reduction on the ground side).  I read a post from Gordon Rankin in another forum a couple of years ago that I interpreted as supporting the ground noise theory, but I don’t know enough to be sure I was interpreting correctly.

 

I don’t know of confirming measurements for either hypothesis at this point.  Because we’re talking about an effect happening in the DAC clock as it’s working, I think the measurements would have to be in the analog domain; or, as John Swenson once mentioned to me, you could essentially build the world’s most precise ADC.

Hi Jud,

 

Jitter  can be measured in the analog domain. It doesn't require the most precise ADC to do so, and if the level of jitter is below the sensitivity of a high quality ADC then is is really audible?

 

I'm willing to experiment, and test out theories. What Peter suggests is not that hard to test: low-pass filtering of USB data transmission and possibly separating power supplies between the input and the output parts of the USB receiver is doable.

 

What John Swenson suggests is harder to test. I have both, regeneration and isolation in my USB chain, but I don't see a way to verify what John is suggesting, except possibly by trying ISO Regen and LPS-1.

[feelingears]

10 hours ago, austinpop said:

 

Thank you, Peter.

Awesome, I look forward to this comparison.

I need yet another USB cable about as much as a hole in my head! But - I am always interested, and keep an open mind.

In general, I do find I can hear cable differences, but they tend to - for me - be subtle, not transformative.

 

And thank you. I've followed @austinpop in the thread formerly known as "Novel Way to Massively Improve" (attempted to, anyway) and now here's this thread... Agreed that another USB cable is about as appealing as an iTunes software update.

 

As you've said, in general I too, can hear cable differences but some of my latest moves are just shy of transformative, bringing the whole together in a product that exceeds the sum of the parts. (Sometimes I hate this hobby.) I post here only to encourage and second said open-mindedness, and thus I "look forward" to spending my money on (sigh) yet another USB cable (instead of the Hana SL cartridge I auditioned a few weeks ago–real analog, right?). 

[PeterSt]

7 hours ago, Ralf11 said:

I mean does Thunderbolt as implemented via USB-C solve (or reduce) the problems in USB 2 as an interface?

 

FWIW, I don't think so. It is the protocol doing the damage (that's a bit tough but alas) and that won't change a thing.

Btw there won't be much difference with using a PCIe interface with USB outputs. And on that part, we (over at Phasure) tried many things regarding this, up to everybody using a Silverstone USB3 card, just because it sounded special. But other elements caught up with it and I don't think many use it any more.

The thing here is, once you can hear a bit more fro your system, everything matters regarding USB. Buy 10 different PCIe cards and they will all sound different and you will keep one as your best one. Until the Operating System changes - then you have to start all over.

Buy a JCat Femto etc. card - that too sounds different.

 

In the end those "tweaks" don't work, because they work by random aids. Your system suffers from something, and the aid will change the sound. Will it be for the better ? actually you will know when you e.g. buy another DAC and suddenly it does not work for the better any more.

From the point of view of the manufacturer it can be looked at differently with the same conclusions : if something works for really everyone, then the application is really good in absolute sense. And the fun is that when working in a quite close group, this is easy to detect (but also carries great responsibility). What I mean is, once an application has been worked out and it works for a 100, then when a first comes along where it does not work, then

a. I need dare to say that something has to be wrong at the customer's end;

b. The customers needs to have an open mind and help searching for the culprit.

 

A bit of a blabla story but this is really how it can work and how everyone can help each other and make progress.

Back to the quote above, what can be predicted is that the speed of e.g. USB3.2 helps to overcome problems in general (the speed is by far not needed for audio but spades of headroom is always a good thing). This is (in my view) how USB3 always sounded better than USB2 (at the PC's end) and how a USB3 hub in the ISO REGEN sounds better than a USB2 hub in the same environment. We shouldn't make this a subject in this topic, but a lot with audio (if not all) is about headroom we don't anticipate because we can so-called calculate it isn't necessary.

[PeterSt]

4 hours ago, pkane2001 said:

I'm willing to experiment, and test out theories. What Peter suggests is not that hard to test: low-pass filtering of USB data transmission and possibly separating power supplies between the input and the output parts of the USB receiver is doable.

 

Hey hey ...

 

I think it was you who responded with a "Cool!" from a conclusion you made yourself; it was a bit hard for me to reply to that because of the way you put it there (as I recall it). But now I can do better. 

 

Low-pass filtering is not going to work out because you will eliminate the data itself. So say that USB transmits 480mbs then you can see this as equivalent to 480MHz in order for the bits (which is analogue square wave) to pass through the cable. And, as someone else nicely presented : plus a bit more or else the square wave is a sine.

So low pass filter that to e.g. 500KHz and no data arrives in the receiver.

 

IIRC you responded to my "tunnel" presentation, which implied "shaping" as such. Call it clipping and technically (electrically) you are where I like to to be. Mind you, this is not at all the same as "band limiting" which is what got to your mind, if I understand correctly.

But no harm done, because the cable already exists.

 

In order to not make this 100% ballony, think oscillator output. This can be square or sine, and both will work for almost all applications. Now sit back and try to reason what will work better for your application.

My promise : now there is suddenly so much involved that a group of fine engineers will get mad from all the ideas each one may bring to the table.

 

[semente]

1 hour ago, PeterSt said:

 

FWIW, I don't think so. It is the protocol doing the damage (that's a bit tough but alas) and that won't change a thing.

Btw there won't be much difference with using a PCIe interface with USB outputs. And on that part, we (over at Phasure) tried many things regarding this, up to everybody using a Silverstone USB3 card, just because it sounded special. But other elements caught up with it and I don't think many use it any more.

The thing here is, once you can hear a bit more fro your system, everything matters regarding USB. Buy 10 different PCIe cards and they will all sound different and you will keep one as your best one. Until the Operating System changes - then you have to start all over.

Buy a JCat Femto etc. card - that too sounds different.

 

In the end those "tweaks" don't work, because they work by random aids. Your system suffers from something, and the aid will change the sound. Will it be for the better ? actually you will know when you e.g. buy another DAC and suddenly it does not work for the better any more.

From the point of view of the manufacturer it can be looked at differently with the same conclusions : if something works for really everyone, then the application is really good in absolute sense. And the fun is that when working in a quite close group, this is easy to detect (but also carries great responsibility). What I mean is, once an application has been worked out and it works for a 100, then when a first comes along where it does not work, then

a. I need dare to say that something has to be wrong at the customer's end;

b. The customers needs to have an open mind and help searching for the culprit.

 

A bit of a blabla story but this is really how it can work and how everyone can help each other and make progress.

Back to the quote above, what can be predicted is that the speed of e.g. USB3.2 helps to overcome problems in general (the speed is by far not needed for audio but spades of headroom is always a good thing). This is (in my view) how USB3 always sounded better than USB2 (at the PC's end) and how a USB3 hub in the ISO REGEN sounds better than a USB2 hub in the same environment. We shouldn't make this a subject in this topic, but a lot with audio (if not all) is about headroom we don't anticipate because we can so-called calculate it isn't necessary.

 

Hi Peter,

 

Have you ever thought about designing a dedicated PCIe USB card?

Wouldn't it be better to have full control over the interface?

 

R 

[PeterSt]

3 minutes ago, semente said:

Have you ever thought about designing a dedicated PCIe USB card?

 

Ricardo, yes. But the result will always be vague in advance.

Secret : in 7 months of time I will have a new interface with very fresh ideas. And that one can be predicted. It is a study project for our Paul (who managed to study embedded engineering without me pushing him) and if I'm right such a project would be for graduated and beyond. He's in his 2nd year soon.

[manisandher]

2 hours ago, PeterSt said:

This is (in my view) how USB3 always sounded better than USB2 (at the PC's end)...

 

FWIW, I have a strong preference for using the USB2 port at the back of the audio PC - it sounds more 'alive' than any of the USB3 slots, with a bit more bite. USB3 sounds full-bodied, but overly-smooth and boring in comparison... in my system... to my ears. (And yes, even with the Lush feeding the Phisolator built into the DAC, different PC ports still sound different.)

 

Mani.

[manisandher]

1 hour ago, PeterSt said:

It is a study project for our Paul (who managed to study embedded engineering without me pushing him) and if I'm right such a project would be for graduated and beyond. He's in his 2nd year soon.

 

Yep, that boy's one smart cookie. Must get it from his mum's side 

 

Mani

[jventer]

I think it is fantastic that people from all over the world can share on this forum.

I have been fortunate to meet Anthony (acg). I have also been fortunate to listen to his PC and his Phasure dac. We had a GTG and I heard this with a Gryphon amp on Lenehan speakers and I can still recall the details! (no loss of audio memory there!)

Thanks for sharing and please keep posting, the Phasure is special. I have no doubt that the Lush will be a hit.

[mmerrill99]

8 hours ago, pkane2001 said:

Hi Jud,

 

Jitter  can be measured in the analog domain. It doesn't require the most precise ADC to do so, and if the level of jitter is below the sensitivity of a high quality ADC then is is really audible?

 

I'm willing to experiment, and test out theories. What Peter suggests is not that hard to test: low-pass filtering of USB data transmission and possibly separating power supplies between the input and the output parts of the USB receiver is doable.

 

What John Swenson suggests is harder to test. I have both, regeneration and isolation in my USB chain, but I don't see a way to verify what John is suggesting, except possibly by trying ISO Regen and LPS-1.

This is what I was trying to establish when you said that you had heard improvements with a DIY USB cable - even if it was only because you injected a cleaner 5V - did you find any measurement difference on the DAC's analog output but you said the only improvement was that drop-outs had stopped!!

 

Have you experimented with different 5V supplies & noted any sound difference (not drop-out differences)? This would be a useful experiment to investigate the possible correlation between measurement vs audible changes, don't you think?

[mmerrill99]

4 hours ago, PeterSt said:

It is the protocol doing the damage (that's a bit tough but alas) and that won't change a thing.

Can you detail your thinking on this?

Do you mean the software side or the hardware side?

[mmerrill99]

4 hours ago, PeterSt said:

Back to the quote above, what can be predicted is that the speed of e.g. USB3.2 helps to overcome problems in general (the speed is by far not needed for audio but spades of headroom is always a good thing). This is (in my view) how USB3 always sounded better than USB2 (at the PC's end) and how a USB3 hub in the ISO REGEN sounds better than a USB2 hub in the same environment.

Not sure this holds up - in USB 3 receiver chips there seem to be two separate engines - a USB 2 engine & USB 3 engine - they each handle their own protocol independently of the other. USB 2 only operates at 480MHz, no faster

 

Your more general point that the chip itself is built to be capable of handling the faster speed USB 3 (5Gbps?) may have some significance though even when it's only handling USB 2.0  480Mbps speed throughput?

 

Faster settling time of on-chip components could well be significant here?

[marce]

On 15/07/2017 at 2:59 PM, pkane2001 said:

 

Does that mean that a HF cutoff filter in the digital USB transmission results in HF rolloff in the analog domain? How does that work?

Nope, only by altering the bit pattern using DSP or similar.

[marce]

On 15/07/2017 at 3:44 PM, mmerrill99 said:

90 ohm is the USB spec specified between USB D+ & D- signal lines but in reality it is more important to ensure 45ohm impedance from each USB signal line to ground & this is not specified, AFAIK?

Rubbish, its a differential signal its the differential impedance that is critical.