Preferred aes/ebu 110 ohm digital cable you have tried

[dallasjustice]

Gary,
Listening test don't matter here. The more impedance is mismatched from AES/EBU standard 110 ohm, the more reflection in the digital cable. The more reflections in the digital cable, the more jitter. If you don't get what I am saying talk to Amir or the engineers at Berkely. If you think jitter isn't audible, that's fine but totally irrelevant.

Fraud is a common practice among cable manufacturers. When a manufacturer advertises a spec and claims superior performance, they must deliver on the spec or it's fraud. In this case I did pay $500 for the 42 ohm cable advertised at 110 ohm. I feel like I got took. I don't have time to file $500 lawsuits, so I can let it go. But it would an easy one to win if I did.

That's very interesting - what was the qualitative difference in sound between the 120 ohm cable and the 42 ohm cable? It would be great to correlate the sound of digital AES/EBU cables to measured impedance. If you can find another manufacturer's 42 ohm (claimed 110 ohm) cable, and it sounds the same as this particular 42 ohm cable, then we have datapoints we can use.

 

[ar-t]

OK, before anyone blows a fuse, I am not out to nail any manufacturers. How they put food on the table is their business, and I have no intention to mess with that. Even if instead they buy fancy cars and expensive watches. Either is fine by me, so there is no vendetta or other nefarious agenda.

This is forum is about "What's best?" Best is a moving target, and one of those "beauty is in the eye's of the beholder" thing. When it comes to amps, and speakers, and what-not, there is no accepted metric to what would even qualify as a starting point.

But when it comes to "digital audio" cables, we have such a metric. SPDIF and AES/EBU have a standardized impedance, and when it comes to "What's best?", it seems like a reasonable assumption that any cable should at least get that right. (Beyond that, you can argue points like how tightly the impedance is controlled or pulse dispersion. But, let's at least get the impedance right.)

My contention is that a lot of cables don't meet the impedance spec. I know that from years of measuring them. Some companies have no clue what their cables are, and don't really care. "We plugged it into our system, and it sounded great, so that is that." Some do, but have no means of measuring it. They farm that out to folks like my company. (And then argue when it isn't what they were told it was.) Others claim they care, yet employ the wrong methods to measure it. And there are probably some that do care, and get it right. There is no point in arguing what the exact percentage of each group. That isn't the point. The point is, in lieu of published data, you have no idea what you are getting.

Now, let's talk about one that claims they care, but are clueless. "Perry Mason" brought a cable to my shop, I had no idea who they are, and don't care who they are. But they are so far off the mark it is a joke.

We will only identify it as "the shiny black cable". Subsequent to measuring it, we poked around on their website. Gee, to hear them talk, you would think they are one of our clients.

Taken directly from their site:

For digital signals............blah, blah, blah.............. reflections on the cable.

*

Yeah! I have been saying that for over 20 years. And there is some other text that sounds like it was written by us.

But then their cable measures 43 ohms!!!!!!!!!!!!!!!!!!!!

It isn't even suitable for SPDIF! Maybe if SPDIF was 50 ohms, but it isn't, so............????????? What were they thinking? Were they even thinking?

Now, I could be wrong, and on the surface, I should be wrong, because no one can really be this stupid, but..........

It looks like they use the same cable for SPDIF and AES/EBU! They talk about how great their cable is, and then mention you can get it terminated with RCAs, or BNCs, or XLRs.

HUH?

Do they really use the same one for all 3? (OK, 2 are basically the same.) But how in the world can you use the same cable for a 75 ohm coax system as a 110 ohm twisted-pair balanced system?

I would love to hear the answer, but since we are not going to mention who the various cables are, that will remain a mystery. Probably until the end of time.

So, to reiterate: In lieu of published data, you have no idea what you are getting. Yeah, these guys talk a good game, but it is all talk.

We will see how the others measure.

"There are others?"

Yeah, a few individuals have accepted our challenge. So, this could be good. Good, as in we will find some brands that get it right, or some that will provide us with tons of amusement. We shall see. Stay tuned!

* = PM advises removing the actual quote. Copyright.

OK, what it really said:

For invincibility, it is essential that you have thunderball fists.

 

[Orb]

Just got back from Pat's house. Using his TDR and another method to verify, we measured a $40 AES/EBU cable. We next measured a "patented" $500 AES/EBU cable. We verified each measurement. The $40 cable measured 120 ohms (pretty good) and the "patented" $500 AES/EBU cable measured 42 ohms (the joke's on you, customer!)

Both manufacturers claim 110 ohm spec. We are going to upload some videos in the near future. We have several more we are going to measure. No manufacturer names will be disclosed. We will only disclose retail price for each cable.

Obviously, we are off to an excellent start!

Any chance though you could post the brands that get close to the 110 ohm spec, I can understand why not posting names of those that are at fault.
BTW I am not too surprised at your result as I have seen same outside of audio when it comes to transmission solutions, price is not a guarantee although I would be pretty sure some (and emphasis some/not many when one considers how many brands exist) of the high end will be pretty close to standard but depends upon which manufacturer used.

One BIG caveat; I would prefer any test result not be done using 2nd-hand purchased cables that cannot be 100% verified they are not fakes.
As an example Siltech... omfg I swear over 90% are fake that are sold on the internet or as 2nd-hand from some selling services, and even then they are sold as new (meaning really needs buying-borrowing from a manufacturers' approved dealer/distributor).

This is a big consideration otherwise any measurements-conclusions is wrongly skewed as this issue is not just limited to Siltech.
Thanks
Orb

 

[microstrip]

OK, before anyone blows a fuse, I am not out to nail any manufacturers. (...)

For digital signals, proper impedance and termination are necessary to prevent reflections on the cable.

You have just identified the cable with the quote ... I hope you also supply quotes for other brands.

I must say that I never heard about these people before.

 

[ar-t]

Ah, you mean there is one and only one that says that? Who knows? You mean that wasn't lifted from our site? We have published very similar text, more than once, over the course of the last 15+ years that we have had our own site.

The only reason we looked at their site was we thought there was chance they shipped a conventional audio interconnect, by accident, instead of a digital one. "PM" even called the dealer (one of his personal buddies) to make sure he had the right one. (His buddy was not amused.) He confirmed it was the right one. I had to read their site to make sure someone wasn't playing a trick on us.

I've seen cables that are way off, but never anything close to this.

I guess we could identify the ones that are decent. Maybe they will hire us to do some work for them.

Anyone else have any ideas about what we should do with the ones that are good? I'm open to suggestions.

 

[mep]

Dallas-What did you think about how the cable that measured 42 ohms sounded before you knew it measured 42 ohms?

 

[microstrip]

(...) Fraud is a common practice among cable manufacturers. When a manufacturer advertises a spec and claims superior performance, they must deliver on the spec or it's fraud. In this case I did pay $500 for the 42 ohm cable advertised at 110 ohm. I feel like I got took. I don't have time to file $500 lawsuits, so I can let it go. But it would an easy one to win if I did.

Are prepared to support such affirmation with data? I have no doubt that there are some cable manufacturers who are cheating us, but I do not feel it is a common practice - IMHO these cases are exceptions. But I can be wrong - I have limited knowledge of digital cables.

Are you going to supply us data of relevant properties of cables versus frequency, as supplied for example by Mogami?

 

[ar-t]

Are you going to supply us data of relevant properties of cables versus frequency, as supplied for example by Mogami?

How exactly is that relevant? How many companies that make "digital cables" provide ANY data?

 

[microstrip]

Ah, you mean there is one and only one that says that? Who knows? You mean that wasn't lifted from our site? We have published very similar text, more than once, over the course of the last 15+ years that we have had our own site.

I hope you know about plagiarism detection software. You told us that the sentence was taken directly from their site and it shows exactly in their site and their marketing literature ...

BTW, Advanced Google also confirms it, and the sentence does not show in your site. But be assured I will not tell anyone.

 

[ar-t]

Dallas-What did you think about how the cable that measured 42 ohms sounded before you knew it measured 42 ohms?

He is a lawyer. He may stretch the truth!

 

[ar-t]

BTW, Advanced Google also confirms it, and the sentence does not show in your site.

Uh, you don't know what name our site used to be called. Is it in their cache? I dunno.

 

[Orb]

Just to add though as it has been hinted at a few times.
The impedance issue is not solely restricted to cables/connectors as one must also consider the CD-transport and DACs due to the digital circuit/connector solution-design-hardware implemented.
Some manufacturers are a fair bit away from the impedance spec for either their RCA or AES/EBU, and further compounding this is the rise time/ripple that is not always uniform across all products sold.

Cheers
Orb

 

[ar-t]

Just to add though as it has been hinted at a few times.
The impedance issue is not solely restricted to cables/connectors as one must also consider the CD-transport and DACs due to the digital circuit/connector solution-design-hardware implemented.
Some manufacturers are a fair bit away from the impedance spec for either their RCA or AES/EBU, and further compounding this is the rise time/ripple that is not always uniform across all products sold.

Cheers
Orb

And that is how one company started selling a 93 ohm cable. Their designer could not do simple math.

 

[microstrip]

How exactly is that relevant? How many companies that make "digital cables" provide ANY data?

You are the expert - do you think that impedance versus frequency is not relevant? I would expect it to be, as most cables have larger rising impedance values with decreasing frequency at frequencies bellow 1 MHz and exhibit some variance even in the MHz zone.

 

[ar-t]

Do you think the impedance is constant along the length of the cable?

Most folks accept a transmission line as something that has the same impedance, regardless of frequency. I hope you do not intend to drag this down to a semantic battle over how low in frequency a cable can act like a transmission line. Not going to play that game.

 

[dallasjustice]

The HD version will be available soon. I will only post the video of the good cable test.
[video=vimeo;94713812]https://vimeo.com/94713812[/video]

 

[BlueFox]

Is it possible to take this measurement stuff to another thread? While semi-interesting, it really is off-topic.

 

[microstrip]

Do you think the impedance is constant along the length of the cable?

Most folks accept a transmission line as something that has the same impedance, regardless of frequency. I hope you do not intend to drag this down to a semantic battle over how low in frequency a cable can act like a transmission line. Not going to play that game.

I can see now that you are not playing any game worth reading. We have real and friendly audio experts in WBF from whom we learn and those that always have a brilliant reason to avoid answering. Bye. I should have understood when it was said you were not interested in listening.

 

[ack]

micro said

IMHO the debate of exact cable impedance is useless if you do not correlate its effect with sound quality - something I have never seen.

and Gary also asked about verification with listening tests... I have found that the best way to demonstrate the effect of digital cable impedance is by using a cable with variable such impedance. And that cable is the MIT MA-X; if you measure the *DC* resistance of its hot and return wires you will notice significant variations - in my 1m, it ranges from 11.5 to 15.6 ohms per wire (i.e. double for the entire path), and their network is clearly in-series with the wires (not only because of this, but also because there are pauses as you switch from setting to setting). Said DC resistance will certainly have an effect on the cable's overall impedance at the operating frequencies, and I just don't know where the 110ohm value is - that would be a good cable for Pat to measure. However, as Orb said, there are also the transmitter and receiver chips in the transport and DAC - therefore, what makes this cable really good is that you can adjust its impedance to match the equipment you have. Unless you buy already matched components with a matched cable to go - e.g. dCS - the other option is to adjust the impedance by ear, or hire someone competent to measure your equipment and adjust the cable. What also doesn't work well is buying fixed "matched" digital cables utilizing networks from companies that _think_ they know what the impedance characteristics of the transport and DAC you are connecting are, as if they have measured everything out there.

So back to the listening tests: with the MA-X in my system you can fairly easily tell the difference between settings (which affect jitter as a result of reflections caused by the various impedance selections) by listening to strings - at one setting they gain all the bite and focus they really have, others give a rather hazy, softer sound. Finally, see this http://www.positive-feedback.com/Issue14/spdif.htm regarding reflections and how they affect jitter.

Great work Michael and Pat... looking forward to your next video.

 

[microstrip]

(...) So back to the listening tests: with the MA-X in my system you can fairly easily tell the difference between settings (which affect jitter as a result of reflections caused by the various impedance selections) by listening to strings - at one setting they gain all the bite and focus they really have, others give a rather hazy, softer sound. Finally, see this http://www.positive-feedback.com/Issue14/spdif.htm regarding reflections and how they affect jitter.
(...)

The article you refer adds weight to what Orb and I have been saying - you have to look at the properties of the sender and the receiver to analyze the problem. You can sue the manufacturer for being out of nominal specification, but these measurements will not not add quality to the sound of YOUR existing system.

BTW, it seems people are assuming that jitter is the only parameter affecting sound quality in an AES/EBU cable. Although I have no experience with systems having an external distributed single clock, that are intrinsically jitter free, I have read that in such systems AES/EBU cables can affect sound quality.