Would forum members chip in $$ for a USB analyzer

[Miska]

8 hours ago, jabbr said:

 

The Ethernet->I2S/DSD interfaces will generally run ARM perhaps with an associated FPGA (e.g. Zynq), but not necessarily (e.g. rPi). Or another SoC such as ClearFog (Armada). Lots of options. Each DAC needs an ALSA driver. A remote network protocol such as netJACK->ALSA or @Miskas NAA would connect. The interface would run some version of Linux, typically. Presumably one could do the same type of thing for Windows IoT.

 

Smallest device I run NAA on is 400 MHz ARM9 with 64 MB RAM. That is good up to stereo 768/32 PCM and DSD256. Power consumption is 750 mW peak.

 

[plissken]

15 minutes ago, Miska said:

 

Well, it is pretty much just PCIexpress on a cable. Companies like RME, Lynx and many others have been making sound cards that perform better than many audiophile DACs and sit inside the computer connecting to the PCIe...

 

Focusrite, Universal Audio and many others already have Thunderbolt interfaces for studios. It allows low latency and huge number of channels at the same time.

 

Of course audiophiles can keep worrying about the noise and all that, while not knowing that the music they've been listening to has been recorded using Thunderbolt connected ADC...

 

 

And no magical regen boondongles.

[The Computer Audiophile]

16 minutes ago, Miska said:

 

Well, it is pretty much just PCIexpress on a cable. Companies like RME, Lynx and many others have been making sound cards that perform better than many audiophile DACs and sit inside the computer connecting to the PCIe...

 

Focusrite, Universal Audio and many others already have Thunderbolt interfaces for studios. It allows low latency and huge number of channels at the same time.

 

Of course audiophiles can keep worrying about the noise and all that, while not knowing that the music they've been listening to has been recorded using Thunderbolt connected ADC...

 

 

Just because it's done doesn't mean it's done for the best sound quality. 

[Miska]

3 minutes ago, The Computer Audiophile said:

 

Just because it's done doesn't mean it's done for the best sound quality. 

 

It also doesn't mean that the devices are technically bad... In fact, there are many great performing pro-audio devices out there.

 

Your USB and Ethernet interfaces are connected to the PCIexpress bus inside your computer anyway. So either USB and Ethernet are then bad too, or then if someone claims PCIe is bad they are incompetent in using it correctly.

 

 

[jabbr]

1 hour ago, Miska said:

Your USB and Ethernet interfaces are connected to the PCIexpress bus inside your computer anyway. So either USB and Ethernet are then bad too, or then if someone claims PCIe is bad they are incompetent in using it correctly.

For PCs the PCIe bus is universal -- not so much for ARM. Moving forward perhaps the interface not for forget will be WiFi. I'd argue for Ethernet over TB from an availability rather that technical POV. Is there something intrinsic to WiFi that makes it less desirable?

[crenca]

3 hours ago, jabbr said:

....is there something intrinsic to WiFi that makes it less desirable?

 

Yes - you can't sell $5k cables for it, or $1k blocks of machined steel to prop up your liquid crystal...oh wait, someone will come out with a crystal-core wifi bridge for $20k that will "really nail the mid-range".  The magical antenna will of course bring benefits that while based in physics, simply are not measurable with current technology - you "just have to listen"  

 

Sometimes this hobby is makes the local pimps look clean...

[Panelhead]

On 6/7/2017 at 9:16 PM, Teresa said:

I agree with Speed Racer perhaps new DACs should move away from USB. Maybe something like Thunderbolt.

  I am using a Thunderbolt connected interface. Even using a TB port and a FW to TB adapter showed much better sonics compared to the FW buss.

  Just picked up a MacBook Pro that only has TB3/USBC ports. Waiting for a four channel dac that utilizes the new buss. 

  For now a Thunderbolt connection is fine. 

  The new TB3/USBC buss should start to appear on studio gear later this year.

[jabbr]

On 6/8/2017 at 9:57 AM, Wavelength said:

USB, USB3, USB-C we made USB easy to work with. We created platforms that allowed digital and analog designers easy access to build their products.

 

You are probably on one of the best positions to answer some of the questions many of us have that have prompted this thread -- there is a seemingly endless proliferation of gadgets and exotic cables designed to "dramatically " improve the sound of DACs connected by USB.

 

What then are the issues with USB that require correction? What are these devices (external USB widgets) doing to the DAC and how can the effects be measured? Can they be measured? Why would it be so hard for DAC manufacturers to isolate their DACs?

[jabbr]

Following to above post : my initial interest in using fiberoptic Ethernet was 1) for the very easy and complete electrical isolation and 2) to try and minimize the idea that we should try to improve SQ by tweaking cables because ... Corning fiberoptic Ethernet cables are cheap and SOA.

 

Aside from that I have no reason to arbitrarily prefer USB vs TB vs Ethernet in fact my Zynq interface would handle all 3 with essentially equal facility. 

[Wavelength]

1 hour ago, jabbr said:

 

You are probably on one of the best positions to answer some of the questions many of us have that have prompted this thread -- there is a seemingly endless proliferation of gadgets and exotic cables designed to "dramatically " improve the sound of DACs connected by USB.

 

What then are the issues with USB that require correction? What are these devices (external USB widgets) doing to the DAC and how can the effects be measured? Can they be measured? Why would it be so hard for DAC manufacturers to isolate their DACs?

Jonathan,

 

Trying to fix a USB problem with one solution is never going to work. This is going to sound like a freaken marketing answer, but... You have basically 5 variables that can interact with each other:

1. Power
2. USB Cable Data integrity
3. USB Cable power
4. Device
5. Host

#5 Ok so everyone knows that not all USB host ports are not created equal. Some are off the main host controller, others off an internal hub with other BS on it. Second not all brands are the same. I always double back on my days designing motherboards and the fact that there were 2 accountants that shared my work space. Not to mention that these things are made for a price point, but also you have to look at the engineering. Were is the motherboard, were are the ports, are these cabled?

 

#4 How well is the downstream port designed? I designed a product for a company one time a rather large company who had their contract manufacturing make some prototypes. The company called me up &%&^%$%& me out. I said send over the schematics and a sample. Crap I am not sure if my reference design was even understood by the company. USB is a differential pair, they had the + signal go like 2" longer than the - leg. It would hardly work Full Speed.

 

3# Power can effect #2, but it can also be effected from outside noise. We have all seen the split cables and the thought that this fixes the effect on data, but some of these missed the other points.

 

2# Look the cable is a huge variable. Even I have learned a bunch in the last 5 years of my 14 years in USB. Well lets face it Full Speed is pretty easy to pull off. Most of these companies took their SPDIF cable and added VBUS & Ground. We even saw companies trying to sell 50-60 foot cables. They hadn't even tried these with DACS, let alone Asynchronous ones which require bi-directional data. On the Tektronix analyzer and a TDR you can test these pretty easily with known Host and Device.

 

1# Power... part of the problem with USB is the common ground. So in the basic sense the computer ground is shared with the USB and the other devices connected to that USB cable. Isolation will fix that problem. But what effects does it have on the rest of the system and were do you isolate? Do you isolate at the I2S or at the USB? The problem with the Silanna and Analog Devices isolators is that they do not reclock the data and therefore any USB Jitter on the data stream coming in will be increased on the other side. This is why putting a HUB on the device side is really necessary. That will reduce the data errors, but can't fix the data errors. At least with I2S isolation you can reclock the data with the known Master Clock which is synchronous with the data and hopefully low jitter so the dac sees exactly what you want it to see.

 

For me I run my power for my system (WWWS speakers, WA Corona Silver VT52 amps, WA Sine6 pre, WA Crimson or Cosecant, MacBook Pro Retina 15, Drobo Quad SSD raid Thunderbolt) as a spit system using CG T filter. One to the mains, one filter to the digital MBP+Drobo+isolated ethernet switch, the other side amps, dac, pre. This way the digital stuff has to go through two filters to infect the other side.

 

I plug my DACS through a Sonnett Ethernet/USB3 Thunderbolt dongle. It works better than the MBP ports. Cables USB AudioQuest Diamond or Curious.

 

Thanks,

Gordon

[Ralf11]

how many pennies per chip are we talking about?

[jabbr]

2 hours ago, Wavelength said:

Trying to fix a USB problem with one solution is never going to work. This is going to sound like a freaken marketing answer, but... You have basically 5 variables that can interact with each other:

1. Power
2. USB Cable Data integrity
3. USB Cable power
4. Device
5. Host

 

Thanks. I know this is the current situation and people like yourself are doing the best to work with the complexities of these interacting factors. 

 

With fiber optic Ethernet perhaps there are less variables. The cables are of uniformly great quality. Likewise transceivers but you can always swap SFP modules. So you eliminate 1,2,3 and just deal with device & host

 

[wgscott]

Wouldn't it be more cost-effective to find someone who already owns the testing equipment to do the tests in exchange for buying them beer for the remainder of their life or something like that?

[esldude]

46 minutes ago, wgscott said:

Wouldn't it be more cost-effective to find someone who already owns the testing equipment to do the tests in exchange for buying them beer for the remainder of their life or something like that?

Wish I could like this 100 times.

[mansr]

48 minutes ago, wgscott said:

Wouldn't it be more cost-effective to find someone who already owns the testing equipment to do the tests in exchange for buying them beer for the remainder of their life or something like that?

So we're looking for an octogenarian with a lab?

[esldude]

1 minute ago, mansr said:

So we're looking for an octogenarian with a lab?

As long as he's not an Aussie it'll be okay.?

[AJ Soundfield]

52 minutes ago, wgscott said:

Wouldn't it be more cost-effective to find someone who already owns the testing equipment to do the tests in exchange for buying them beer for the remainder of their life or something like that?

In that case, I own the required test equipment

[mansr]

3 minutes ago, mansr said:

So we're looking for an octogenarian with a lab?

I suppose a golden retriever is close enough to a lab. How old are you, Bill?

[Jud]

I own this lab.  She'll be 8 in September, and her personality hasn't changed.

 

 

[jtwrace]

On 6/7/2017 at 4:34 PM, Miska said:

 

...that's why I always prefer sticking to measure the DAC output instead of any intermediate step... I can replace things from DAC upstream and see how it affects (or not) things that come out from the DAC. That's in the end what matters. And quite many of the interactions actually happen inside the DAC, even though some upstream equipment's involvement is needed for that thing.

Exactly!  Output is damn important.  Hence the reason Amir was doing what he did...

[wgscott]

15 hours ago, mansr said:

I suppose a golden retriever is close enough to a lab. How old are you, Bill?

 

I'm 54, and I do have a lab (although different -- and for this, irrelevant equipment), and hardly ever drink, so a lifetime supply of beer would only put you back a few bucks/pounds/rubles/scheckles/euros/turkish lira.

[AnotherSpin]

Now I see. Consumption of alcohol presses audiophiles to search for what may be considered objective scientific data to support their own hazy subjective impressions from listening audio.

[rando]

1 hour ago, wgscott said:

 

I'm 54, and I do have a lab (although different -- and for this, irrelevant equipment), and hardly ever drink, so a lifetime supply of beer would only put you back a few bucks/pounds/rubles/scheckles/euros/turkish lira.

 

Spoken like a man who can look self improvement in the eye and walk in the other direction.