USB audio cracked... finally!

[manisandher]

1 minute ago, AJ Soundfield said:

Sure.  Is this the "famous only one in the world, magic can be heard, can't be measured widget"? A usb cable??

 

Mr Jadusingh, behave yourself now - you're on a public forum with many others reading.

 

Mani.

[vortecjr]

Have you explored the new Uptone Audio USPCB A>B Adapter which is only 35 USD? 

 

According to Uptone's website https://uptoneaudio.com/products/uspcb-a-b-adapter it's, "Carefully designed with a 4-layer circuit board, we took into account even the mass of the connectors and the widths and thicknesses of the traces. So this new adapter perfectly preserves signal integrity and impedance match.  IT IS BETTER THAN ANY USB CABLE!"

 

Seems great minds (Peter and John) think alike.

[vortecjr]

4 minutes ago, mourip said:

 

Reads as enthusiasm to me. Why bother to say this?

Agree. Mani has historically been a big follower / supporter of Peter's. If Peter can afford to dig a lake behind his house surely he could afford ad here:) I read it as enthusiasm and I trust Mani.

[manisandher]

5 minutes ago, vortecjr said:

Have you explored the new Uptone Audio USPCB A>B Adapter which is only 35 USD?

 

I haven't, but others who have seem to like it.

 

I suspect it'd sound similar to the Phasure Clarixa cable, which also matches the USB 2.0 specs as closely as possible. And I have a strong preference for the Lush over the Clarixa.

 

Mani.

[vortecjr]

12 minutes ago, manisandher said:

 

I haven't, but others who have seem to like it.

 

I suspect it'd sound similar to the Phasure Clarixa cable, which also matches the USB 2.0 specs as closely as possible. And I have a strong preference for the Lush over the Clarixa.

 

Mani.

I don't know anything about the design of the Uptone Audio USPCB A>B Adapter, but maybe it can be tuned. Did I just invent USPCB adapter rolling:) 

[manisandher]

6 minutes ago, AJ Soundfield said:

So other than the you've finally cracked thing, this is/not the audibly unmeasurable widget...a usb cable?

 

PeterSt has never produced an "audibly [sic] unmeasurable widget". Ammar, there really is nothing for you here. Now just move along.

 

Mani.

[JoeWhip]

45 minutes ago, mourip said:

 

Reads as enthusiasm to me. Why bother to say this?

Simply due to Mani's history talking up Phasure and talking down other DACs. This whole things reads a lot more like pushing Phasure than simple enthusiasm. If Phasure wants to send me a cable, I'll listen and report. Otherwise, not interested.

[manisandher]

1 minute ago, JoeWhip said:

Otherwise, not interested.

 

Hallelujah!

 

Mani.

[The Computer Audiophile]

@AJ Soundfield If you have nothing to offer the discussion, stay out. I've removed some of your posts. 

[manisandher]

5 hours ago, BigAlMc said:

Thanks for taking the time to post such a detailed description. 

 

Hi Alan, thanks. (Sorry for not replying earlier - your post got swamped in the ensuing noise.)

 

5 hours ago, BigAlMc said:

I guess the question many will have is how the Lush cable compares to the Uptone USPCB connector that many on CA are raving about currently. Have you had a chance to compare these two? 

 

As I've mentioned in another reply, I haven't heard the USPCB.

 

5 hours ago, BigAlMc said:

Given the cost and reported performance of the USPCB it seems a no brainer where physical space permits.

 

I would have agreed with you totally, up until a few days ago before I received my Lush. Let me just remind you of something I said earlier:

 

21 hours ago, manisandher said:

My understanding is that Peter (with his differently-wired brain) wondered whether the regular USB spec was necessarily the best for audio. And in a manner that is totally incomprehensible to me, decided that it was not. He sat down and worked out his own ultimate spec for USB audio… and built a cable matching it. The result is his new USB cable, the ‘Lush’:

 

By design, the Lush does not follow the USB 2.0 spec, it follows Peter's own 'USB audio spec'. And this 'USB audio spec' was created not in an ad-hoc manner, but from working from first principles. It is my strong belief that it is the adherence of the Lush to Peter's new 'USB audio spec' that gives it its unique musicality. [And I think 'unique' is the correct word here, because I doubt any other USB cable sounds like it.]

 

Now that I've had this level of musicality in my system for the very first time since switching to USB audio, I couldn't live with anything less musical. And I suspect all USB cables/connectors adhering to the USB 2.0 spec would be.

 

HTH.

 

Mani.

[BigAlMc]

Hi Mani, 

 

I'm not technical enough to know if this is a stupid question but if there is a USB output port (server, NAA, computer etc), a cable (the Lush) and a USB input port (DAC, ISO Regen etc) then does the cable get to drive that its PeterSt's non USB 2.0 protocol being distributed? In other words would my Microrendu and ISO Regen in my case not still be supporting USB 2.0? 

 

Regards, 

Alan 

[semente]

1 minute ago, BigAlMc said:

Hi Mani, 

 

I'm not technical enough to know if this is a stupid question but if there is a USB output port (server, NAA, computer etc), a cable (the Lush) and a USB input port (DAC, ISO Regen etc) then does the cable get to drive that its PeterSt's non USB 2.0 protocol being distributed? In other words would my Microrendu and ISO Regen in my case not still be supporting USB 2.0? 

 

Regards, 

Alan 

 

I'd ask that question to Peter but my guess is that we are facing an improved USB 2 spec and not a departure from it.

[pkane2001]

12 hours ago, mmerrill99 said:

I can  tell you that the LNC cable above also sounds lush because it cuts off some HF (as well as noise hash)

 

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?

[lmitche]

The Lush cable sounds terrific.  Where can I order one? Is it male USB A to male USB B?

[BigAlMc]

12 minutes ago, semente said:

 

I'd ask that question to Peter but my guess is that we are facing an improved USB 2 spec and not a departure from it.

Yeah I guess that makes sense. Peter might not wish to share his secret sauce too I suppose. 

[jabbr]

1 hour ago, manisandher said:

By design, the Lush does not follow the USB 2.0 spec, it follows Peter's own 'USB audio spec'. And this 'USB audio spec' was created not in an ad-hoc manner, but from working from first principles. It is my strong belief that it is the adherence of the Lush to Peter's new 'USB audio spec' that gives it its unique musicality. [And I think 'unique' is the correct word here, because I doubt any other USB cable sounds like it.]

 

Now that I've had this level of musicality in my system for the very first time since switching to USB audio, I couldn't live with anything less musical. And I suspect all USB cables/connectors adhering to the USB 2.0 spec would be.

 

Hi Mani, really interesting. What is the "USB audio spec?" Is 90 Ohm impedance not optimal? Or is it something else?

 

[mmerrill99]

1 hour ago, manisandher said:

By design, the Lush does not follow the USB 2.0 spec, it follows Peter's own 'USB audio spec'.

That is interesting, manis as one of the main problems with USB is slowly being revealed as noise on the USB signal lines, not on the ground or 5V line

 

Now this noise on the USB signal lines, it will be argued isn't a problem based on two factors:

- USB lines are differential & therefore noise is eliminated

- noise which gets through should be handled by a "competently designed" audio device

 

The effectiveness of differential cancelling of noise is dependent on the balance between the two lines - the USB + & - signal lines. If these are not the same length, not the same impedance, not the same timing - if the noise isn't equal on both lines for whatever reason, it's differential elimination will be affected. That's related to differential noise but another type of noise, common mode noise also plagues USB cables. CM noise is not removed by differential methods, it requires CM chokes. The broadband & varying nature of this CM noise is not easily addressed using CM chokes - that's why the LNC cable I linked to above, worked so well - it attenuates noise over a wide frequency range.

 

Can other aspects of USB cable construction affect the noise carried on it? Yes, of course there are many aspects that can - differential noise is supposed to be equal & opposite on both wires in a differential circuit in order to be effective - the construct of the cable very much determines this. Ground wire & shield construction are part & parcel of this consideration.

 

Interestingly the 90 ohm impedance spec may not be the best target impedance to aim for in a cable construction

 

Similarly, the 17.78mA constant current used for signalling in high speed USB communication may not be the optimal?

 

Both of these are part of the USB spec - interested to hear if Peterst has addressed these in any way?   

 

Noise which gets through & how it interacts with the digital to analogue conversion is the final question that needs to be investigated & its action mechanisms determined

[mmerrill99]

37 minutes ago, 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?

As I said above

 

1 minute ago, mmerrill99 said:

Noise which gets through & how it interacts with the digital to analogue conversion is the final question that needs to be investigated & its action mechanisms determined

 

It may be that the USB signals withing the USB microframes (talking high speed USB 2 here) are essentially square wave electrical waveforms being communicated via the USB signal wires. These squarewaves have a risetime & falltime - anything which changes the shape of these signals from their optimal shape may well have an effect within a USB DAC - the exact mechanism of operation is still unknown 

[mmerrill99]

16 minutes ago, jabbr said:

 

Hi Mani, really interesting. What is the "USB audio spec?" Is 90 Ohm impedance not optimal? Or is it something else?

 

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?

[manisandher]

49 minutes ago, BigAlMc said:

In other words would my Microrendu and ISO Regen in my case not still be supporting USB 2.0?

 

Alan, apparently, very few USB cables measure anywhere near the USB 2.0 spec - my understanding is that it's quite difficult to achieve. But nevertheless, these cables 'work' perfectly well with your setup (in that there are no drop-outs, etc.).

 

PeterSt believes that his 'Clarixa' cable measures closer to the USB 2.0 spec than any other available. And they're the best USB cables I'd come across... until I heard the Lush in my system a few days ago.

 

The Lush deliberately deviates from the USB 2.0 spec in line with PeterSt's thinking, but not to the extent that it won't work in your (or anybody else's) setup.

 

Mani.

[manisandher]

1 hour ago, lmitche said:

The Lush cable sounds terrific.  Where can I order one? Is it male USB A to male USB B?

 

Yep, male USB A to male USB B. Best to contact PeterSt - sales at phasure dot com.

 

Mani.

[ClothEars]

10 hours ago, 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.

 

I will be very interested to hear your thoughts on the Lush and the Curious cables. In fact if you are in Brisbum I use Curious cables and would be happy to host a test.

[manisandher]

31 minutes ago, jabbr said:

 

Hi Mani, really interesting. What is the "USB audio spec?" Is 90 Ohm impedance not optimal? Or is it something else?

 

 

Hey Jonathan, I have no idea about this stuff - you'll have to see how forthcoming PeterSt is about it. I did ask my 5 year-old, and he was adamant that the correct value is 3 Ω (in-joke between Peter and me).

 

Mani.

[BigAlMc]

7 minutes ago, manisandher said:

 

Alan, apparently, very few USB cables measure anywhere near the USB 2.0 spec - my understanding is that it's quite difficult to achieve. But nevertheless, these cables 'work' perfectly well with your setup (in that there are no drop-outs, etc.).

 

PeterSt believes that his 'Clarixa' cable measures closer to the USB 2.0 spec than any other available. And they're the best USB cables I'd come across... until I heard the Lush in my system a few days ago.

 

The Lush deliberately deviates from the USB 2.0 spec in line with PeterSt's thinking, but not to the extent that it won't work in your (or anybody else's) setup.

 

Mani.

Thanks Mani, 

 

It's certainly intrigued me. 

 

I have the Curious USB cable and I'm very impressed with that. But at 200 euro this Lush one could be worth a try. 

 

Regards, 

Alan 

[scan80269]

There are two main transfer protocols covered in the USB 2.0 specification: bulk transfer mode - used mainly by storage devices such as flash drives and external USB hard drives, and isochronous transfer mode, using by streaming devices such as webcams and modern DACs.  Specifically, DACs tend to use "isochronous transfer mode with asynchronous feedback" for digital audio data transfer over USB.  This transfer mode does not support data re-sending upon error detection by the receiver.  It favors predictable data transfer bandwidth and latency over data integrity.

 

I suspect there is a fair amount of unavoidable periodicity in this isochronous transfer mode.  For example, packet rate is 8KHz.  In contrast, the bulk transfer mode, by not guaranteeing transfer bandwidth or latency, may actually be less periodic in the way the data fly over the cable from sender to receiver.  Is it possibly what Peter has figured out, by making his DAC support only USB bulk transfer mode, along with a deep FIFO data buffer to smooth out the extreme irregularities of USB data arriving at the DAC?

 

I also wonder if a USB cable designed to intentionally affect the error rate of USB data transfer can affect the sound.  The transfer protocol is negotiated between the USB host controller and the USB device (e.g. DAC), and the USB cable being a passive design cannot influence the protocol negotiation in any way, but the cable is in a position to alter data transmission integrity.  Is this perhaps a case where the most spec compliant USB cable design (e.g. 90 ohm differential impedance) may not translate to the most desired sound???  If a USB cable can induce a certain amount of random data transmission errors the increased randomness in how the data goes over the cable *may* be sonically beneficial?

 

Just thinking out loud here...