Corning USB optical cable


#41

Boy it is really dangerous drinking Pilsner Urquell, reading PS Audio, and having an Amazon account… ooo boy…

I just ordered the Corning product … $80 total for a 10 meter version. Reliability reviews should have scared me off… no, Pilsner Urquell gives you strength!!!

I am not too optimistic, I purchased an Audioquest jitterbug for $50… not so sure I can hear anything… I swore off these gadgets but I attribute it all to the Pilsner Effect… well known in scientific circles… If it wasn’t for parties and booze, few of us would be here… now in 9 days I am going to take receipt of a 10 meter bouncing baby optical cable. yay.

Peace
Bruce in Philly


#42

The Corning cable still has thin copper wire for +5v and ground. Only the data lines are optical. It’s not a panacea for DAC isolation from source, sorry.


#43

Darn beer… I didn;t realize… thanx… I just tried to cancel the order… hopefully it will go through.

Thanx again.

Peace
Bruce in Philly


#44

Still most of the noise that gets on the power and ground lines of USB cables come from the data lines - the 3.Optical cables sidestep this problem. The copper wires are also quite thin so they attenuate the power noise and ground noise (if there’s any other path with better conductors between the source and destination the majority of current will run in that.) They aren’t perfect but they are better than many alternatives with higher price tags.


#45

Post TEds reply you might want to cancel that cancel. LOL


#46

Do I want it? Yes, no , wait, yes, no, maybe, well, no yes…

I am finding that I have a threshold of $97.53. If I can get something under that, I usually buy it… doesn’t matter what it is, I buy it.

Peace
Bruce in Philly


#47

Bruce,
Try the Corning USB cable, sure. As Ted says, It will be better than going all metal and wasting money on purifiers etc. However…
I was in your position 9 months ago, in trying to ‘fix’ usb, then tried a $50 China usb-to-TOSLINK converter and my jaw dropped. Glorious transparency. Zero RF noise intrusion to the DAC. One by one. I dispensed with all my gadgets and misc cables. I can run 24/192 no probs and am 100% sure I now hear the DS as it was meant to be.
Dan


#48

Wow Dan, thanx for the tip!!! I mean $50 is under my trigger-threshold of $97.53… so I will buy it!!! Wait, what is it? Hmm… let me read what you wrote…

Oh cool! So, what model exactly? I found items on eBay from Hong Kong for about $78 with shipping denoted as “Asynchronous XMOS U8 USB to Coaxial Optical SPDIF 192K TCXO 0.1PPM Audio 24Bit”

Was this it?

I purchased a few DSD 128 from L2 Recordings… wonder if it will pass this… and then there is the issue of varying optical cable capacity… hmmm

Anymore information on this? Keeping it under $97.53 of course.

Peace
Bruce in Philly


#49

Bruce,


https://m.aliexpress.com/item/32813688802.html?trace=wwwdetail2mobilesitedetail&productId=32813688802&productSubject=HIFI-AUDIO-supply-voltage-Asynchronous-USB-XMOS-U8-DAC-coaxial-optical-fiber-digital-interface-MuRata-Audio

I got it with the golden clock.

Dan


#50

Yea, same one I found on eBay:

I need to wait to see if my cancellation on Amazon went through… it was from a third party seller.

Peace
Bruce in Philly


#51

Cheers Ted. This interesting - I’d never seen noise & USB cables explained this way.

I’ve mostly seen the ground line discussed by John Swenson / Intona / iFi Audio when they all discuss galvanic isolation (and John discussing leakage currents travelling via the USB ground lines). Sometimes the need for clean power lines is discussed, mostly for DACs that are bus powered of course.

But I don’t think I’ve ever seen anyone say the data lines are the main offenders.

Is this noise that gets on the power and ground lines the packet noise that’s often discussed? Or noise associated with leakage currents? Or both? Or other noise?

I need to find my Corning and have another listen - it’s packed in a box somewhere.


#52

There can be noise from ground loops, they’re very system specific, but more or less independent of being a USB cable, or, for example, a RCA cable.

But noise from "USB"ness could be radiated or conducted. Since the data lines are speced to differential on a twisted pair they don’t radiate as much as they might otherwise. But most people are worried about the VBUS (or the “5V”) line and many cables try to work without that line. The noise on the VBUS line can come from the USB source and/or any USB hub on the USB tree and often is generated by switching power supplies. John is right that power supply leakage currents can be a problem. Still a lot of people don’t think about running a power line parallel to a pair of high frequency digital lines: they can pick up noise from the digital lines and if you aren’t careful, can inject that noisy power right into the power supply of the USB device. This noise is indeed data dependent.

But a point of clarification, often packet noise isn’t conducted or radiated as much as induced clock jitter: USB specs a packet rate of 8KHz, but if your sample rate is 44.1KHz (or multiples thereof) then the number of samples in each USB packet have to vary - so the USB device can’t just multiply up the 8K to a good clock, it has to smooth out the average number of received samples in the packets of different sizes and use that to drive the clock. This is a noisy process…


#53

Thanks @tedsmith . I know coiling electrical cables can be a bad idea (magnetic field).

But can you see any issues with coiling the Corning cable? Mine is 10m song and I need only 1.5m - so most of it is in a nice small coil.

I’m hoping the optical feature of the Corning helps in some way to make a nice neat coil a non issue, in terms of magnetic field or RF pickup/radiation…


#54

My extra is in a 8" coil behind the DAC: I don’t really know which problems might be the worst but the power and ground are parallel in the cable and so are effectively a differential pair which cancels out any flux going thru that loop. A tight coil also lessens the size of any bigger ground loop between the DAC and the rest of the system which should lessen the ground current in the bigger loop (as well as 3.Optical probably being a larger resistance than anything else in your system.)


#55

NICE. Thanks for the background info too. I’ve pulled the Corning out of the box for a long listening session.

I’ve seen Rob Watts say a warmer sound with digital stuff (cables, sources etc) is normally a good sign of lower RF as it results in lower IM distortion. And brighter can mean increased RF and increased distortion, creating the artificially brighter sound (mistaken for more detail).

So the first thing I listen for with USB gadgets (this isn’t a normal cable since it features optical converters, so I’ll call it a gadget) is if it makes things sound brighter or warmer or no different, to a direct USB connection to my Mac.

After a long listening session I notice things sounding a little bit warmer with the Corning.

Makes sense, considering all the technical stuff you’ve shared about the benefits (noise and RF) of the Corning.


#56

Just another question Ted. Are you still connecting your Corning to a powered USB hub before your DS DAC?

If so, given the benefits of the Corning, what does a powered hub add, especially since the DS hardly uses any power on the 5V line.

I understand the reasoning for using a hub right before the DAC, powered by a low noise (and low leakage currents hopefully) PSU.

But I thought the Corning would negative this, unless someone is using a bus powered DAC of course.

Cheers


#57

I either use a powered hub or I use the 3.Optical cable - when on the road it’s sometimes hard to get the 3.Optical cable working in an arbitrary system, but the powered hub is reliable. At the house I usually use the 3.Optical cable.


#58

Awesome. I had incorrectly assumed you used them together, at home.

Thanks again for all the info.