Blue Jeans Cat6A Data Cables

SCompRacer

headrott wrote: »

I was ribbing you about vinyl Rich! It's a great sounding format!

I love the sound of vinyl, just not dealing with it's "neediness" in the cleaning and maintnence of it. I guess that's one reason I still have my TEAC X-2000R reel to reel deck. It's not quite the same as vinyl, but still gives me that pure anaolg sound. Beautiful!

I would guess it's the SACD's themselves as well, but it's interesting that all 3 of my PG SACD's do it. It seems that (by chance) at least one would not have the dropout issue.

That's interesting about the Dayton OmniMic V2. In my expreience with Denon CD players (particularly older ones such as the DCD-3000) that Denon lasers can be "finicky" with some CD's. It does not make much sense that it would read it the first time, but fail the second and thereafter. It does make some sense that the Denon would read it after you burned it onto a CD-R as the player is then reading it from a totally different media disc. Obviously, in that case (the OmniMic V2) it must be due to the disc itself.

No worries here, I can take it. True dat about vinyl, it's maintenance and care. I still have to run into the basement to plug in the air compressor too. Someday I'll get that remote AC thing done.... I clean records once and dry brush. No Cheetos or pizza rolls allowed while handling records. No matter what you do, you'll get an occasional pop or tick with some LP's. Nice tape deck! I have an old Pioneer R2R but not many tapes.

My ModWright Sony 9100ES was touchy about reading a particular brand of blue CDR. This Denon 3910 has been pretty good with CDR's folks have brought over. I emailed Dayton to see about a replacement CD.

mccarty250

That's a great ethos. I applaud you on being able to keep up with newer music, I'm rapidly losing touch, only a few modern bands I listen to. Are you actually getting master quality source at that bitrate? Let me ask you another question...when I'm streaming 96/24 audio I achieve sustained transfer rates of around 4mbps, what the heck sustained transfer rate is 5 and change MHZ (!!!) producing???? How big is an album in that format?

SCompRacer wrote: »

I'm over 60 and lost some in the higher freq range, but still pretty good considering I embraced hearing protection late in life. I've had thousands invested in cabling but am pretty modest now. Give me quality copper of suitable gauge and I'm happy.

The hi rez capability is an investment in the future. My past history has shown I can embrace some new and current music, so if something I like is recorded well in hi rez that's a good thing. Conversion to hi rez also takes advantage of different filtering in a DAC. Is it better or different is left to the individual. Sometimes we chase different and call it better. An old guy once told me that when I was younger, now I tend to believe it.

And I was wrong about using 586B; I used 586A on my wall jacks. I looked in the house build file and found my 'SAVE THIS' wiring guide from 13 years ago. As stated the termination at the other end has to match.

KurtBJC

mccarty250 wrote: »

I'm not sure what other variables were involved in your two file transfers but two cat6a cables will transfer at the same data rate using the same speed rated NIC's at both ends unless there is something physically wrong with a cable generating an impedance mismatch and retransmits or some such.

mccarty250, I saw this thread and thought I'd jump in and comment on this; I'm Kurt Denke, owner of Blue Jeans Cable in Seattle WA, the manufacturer of the patch cord used by SCompRacer.

I agree with you, in principle, but I strongly suspect that the speed difference SCompRacer reports in his file transfer is for real. The surprising thing is that HUGE numbers of patch cords on the market fail their stated spec, and when we tested 20 different so-called Cat 6 and 6a patch cords from a variety of retail vendors on our Fluke DTX certification tester, sixteen failed their stated specs, and eleven of them not only failed their stated spec, but also failed the Cat 5e spec. So, what is happening, in my view, to a lot of users is that they are indeed seeing different performance with different patch cords; this would be inexplicable if we assume that all of the patch cords meet spec, but once we realize that many of them fail it miserably (one "Cat 6" cable we tested failed the 5e return loss spec by 8 dB!), the likelihood of real-world differences in use really does loom large.

My own anecdotal experience -- which I have not generally shared because when you're a vendor people aren't prone to trusting your own testimonials -- is that in running streaming video through our wired home network, patch cords made a huge difference. Using miscellaneous patch cords of unknown origin (we just used whatever was lying around -- until six months ago our company was not really in the Ethernet cable business except in a very marginal way) we had a channel that failed the 5e spec, despite having very high-quality installed runs (Belden 1700A) in the walls. The TDR report on the DTX was very clear: there were massive impedance variations in the patch cords at each end, represented by wildly rising and falling traces, and a long flat segment in the middle representing the installed cable. We replaced the patch cords, had a 10 dB improvement in return loss, and suddenly video which had been quite choppy was continuous and clear. This was not a squint-and-strain-and-try-to-convince-yourself-it's-real difference -- it was dramatic.

People in bulk cable manufacture and in testing -- engineers at Belden and at Fluke -- have told me that patch cords on the consumer market (as well as a good many in the professional market) are quite poor. Fluke, some years back, found an 80% failure rate, which happens to match our result (4 of our 20 sample cables purchased met their stated specs) exactly. When you're pushing word processing documents across a not-so-busy network, of course, this usually just doesn't make a noticeable difference -- but when you're running real-time streams, or moving large files, it certainly can.

Again, I agree with your statement. "nless there is something physically wrong with a cable" data rates should be the same with any two cables of the same type. But getting consistent impedance, and getting the right lay length relationships within the cable to minimize crosstalk, and terminating the cable without creating huge RL or NEXT spikes at the ends, is not as easy as people think, and there are indeed a lot of cables on the market which do have "something physically wrong" with them.

Kurt
Blue Jeans Cable

pitdogg2

Thanks Kurt for the detailed account of your experience. I strongly suspect that this is the reason so many are finding differences in HDMI cables also. As you stated " the lay of the cable" and "termination of the end" may in fact have a ton to do with the differences some see and hear.

It is VERY nice to hear(or not) that there are so many cables on the market that are failing in a BIG away. Thanks for your research into this matter

dkg999

Kurt - thanks for contributing to the discussion! One of the reasons I am a loyal BJC customer!

disneyjoe7

Being someone whom works with different cables for signals T3 coax, optical 10gig circuits, and ethernet router / switches. I can see how a cable itself could be an issue and round off square signals and cause issues with bandwith.

Not all cables are built the same.... Being analog or digital.

KurtBJC

pitdogg2 wrote: »

I strongly suspect that this is the reason so many are finding differences in HDMI cables also.

It would not surprise me at all. HDMI is more difficult to produce than Ethernet cable in various ways -- individually shielded pairs are themselves a tricky bit of business in more ways than you might think -- and with as much as 6.0 Gbps in each pair under the 2.0 spec, we're really asking more of twisted pairs than twisted pairs are naturally capable of. I'm amazed it works at all. This is why we have done our HDMI in bonded pair -- it's very good from a return loss and skew standpoint. Unfortunately, this message sometimes gets lost in all the market noise--people see the higher price of the US-manufactured cable stock and they assume it's all nonsense and markup.

Kurt
Blue Jeans Cable

pitdogg2

KurtBJC wrote: »

It would not surprise me at all. HDMI is more difficult to produce than Ethernet cable in various ways -- individually shielded pairs are themselves a tricky bit of business in more ways than you might think -- and with as much as 6.0 Gbps in each pair under the 2.0 spec, we're really asking more of twisted pairs than twisted pairs are naturally capable of. I'm amazed it works at all. This is why we have done our HDMI in bonded pair -- it's very good from a return loss and skew standpoint. Unfortunately, this message sometimes gets lost in all the market noise--people see the higher price of the US-manufactured cable stock and they assume it's all nonsense and markup.

Kurt
Blue Jeans Cable

Bonded pair? Kurt could you elaborate a little more on this. We have recently had some discussion on this here lately. I've also noticed of late that most HDMI is now 28-30 gauge wire that is like hair strands. Although I suspect going from say 22-24 gauge that they were in the beginning to the 28-30 has more to do with the increase in data return and stuffing more wire in a tiny space but still like you said we keep asking for it to do more and more without increasing the space needed for better quality wire per say

KurtBJC

pitdogg2 wrote: »

Bonded pair? Kurt could you elaborate a little more on this. We have recently had some discussion on this here lately. I've also noticed of late that most HDMI is now 28-30 gauge wire that is like hair strands. Although I suspect going from say 22-24 gauge that they were in the beginning to the 28-30 has more to do with the increase in data return and stuffing more wire in a tiny space but still like you said we keep asking for it to do more and more without increasing the space needed for better quality wire per say

Bonded pair is a technology Belden invented for use in paired data cabling, and which we use in our Series-FE and 1E (and predecessors, Series-F2 and 1) HDMI cables. Where a conventional data pair is two insulated wires twisted together, a bonded pair actually has the insulation of the one wire bonded to that of the other. This means better control over pair spacing, as well as less movement in pair spacing when the cable is flexed. Since pair spacing is critical to impedance stability, this means better performance at higher frequencies where small impedance variations become increasingly critical.

A lot of the tiny HDMI cable you're seeing now is active cable -- the Redmere chips being the most popular of the sort. It does save on copper, and people are wowed by the unusual size, but of course one should stay away from active solutions whenever possible--it's just one more failure point in the system. Now, that said, it's quite possible that active cables are the way things are going -- the difficulty of distance runs in HDMI 2.0 may be quite severe. It's already quite severe under 1.4, but the thing is that very few people are straining the bandwidth limits--there's not much that runs at 3.4 Gbps. With 4K at 60 fps, a lot of cable that's been working up till now will stop working.

Kurt
BJC

pitdogg2

Thanks Kurt,

this is where I'm coming from see this link starting at post #33

http://www.polkaudio.com/forums/showthread.php?155792-Recommend-a-HDMI-cable/page2

Electrolytic tough pitch copper Bonded pairs. This is where we are confused as to why this is better or if we are just wrong.

By the way I hope you know we steer a lot of buyers your way....

Sorry for the slight derail OP but why we have Kurt here to shed some light it would be beneficial for all.

Speedskater

A Belden Blog on Bonded pairs:

"Twisting the Night Away - Part 2"

Posted by: Steve Lampen on January 29, 2013
Blog Category: Broadcast AV

http://www.belden.com/blog/index.cfm?authorID=1000035&postedby=Steve%20Lampen

Note that Steve Lampen has over 70 blog pages and 2 books on audio/video cabling.

KurtBJC

Yow! Lots of hostility in that thread.

First, "bonded pair" refers to an entirely different attribute of the cable than the copper type; one could do bonded pairs in OFHC or in ETP copper just as easily. Bonded pair is all about stabilizing the relationship between the wires in a pair, without regard to what those wires are made of.

Now, ETP versus OFHC: this is something which, due to good old FUD, has become the subject of far, far more discussion than it ever really deserved. There are mornings, sometimes, when I wake up and wish that we'd just insisted on using bloody OFHC in every one of our products just so that we'd stop having to explain it -- but just as we have taken a stand against insisting on magical qualities to other special materials (e.g., Teflon dielectrics being used other than for plenum cable, silver plating on copper wire as improving sound or video quality, et cetera) we have never been much inclined to bow to common misconceptions on OFHC. In fact, really the only area where we have given in to common misconceptions is connector plating: I'd rather have a nickel-plated HDMI connector, for example, than gold, but if we did that, it would fly too much in the face of the conventional wisdom and we'd really suffer for it.

Let's start out with a couple of observations about ETP. Contrary to some of the remarks in that thread, ETP is not some sort of garbage-grade copper. All of our 3G SDI cable (and probably all of the 3G SDI cable made by everybody else, for that matter) is ETP. All non-esoteric network cable is ETP. Until a few years ago when a special application for a particular customer came along, Belden, the largest manufacturer of communications cabling in the world, did not even keep OFHC on hand. ETP is great stuff. And if you think that tiny, tiny differences in the amount of oxygen (don't forget that the 0.05% of ETP that isn't copper isn't all oxygen -- it's the sum of ALL impurities) make a cable start to degrade internally, grab a piece of 20-year old coax made with ETP and a nitrogen-foam dielectric and strip it; you will find bright copper inside that looks like it just came out of the wire drawing machine five minutes ago.

I happened to make my first visit to the Belden Engineering Center in Richmond, Indiana just about the time they started actually stocking OFHC for the first time ever, and in a meeting with the engineering staff it was suggested to me that perhaps we should use it for speaker cable because the customers might want it -- but there was not one engineer in the room who could say that without a nervous giggle, or a funny smile, or a knowing wink, because there was not one of them there who thought there was any advantage in using it. Not in SDI coax, not in network cable, not in microwave jumpers, not in industrial control cable, not in speaker cable, not in telephone cable, not in anything in the alphabet from AES cables to YUV cable (sorry, couldn't think of a cable type that starts with "Z"). And, as the engineers already knew then but came to know even better as we got to know each other over the coming years, we didn't want to specify materials out of a concession to popular misconceptions. Our insistence on using good engineering justification for design is one of the reasons we get along with the engineering staff, who have helped us in countless ways, so well.

Now, I'm familiar with the Audioholics article quoted in that thread, but I'm not sure of the details given on the OFHC thing, especially as to the claim that bad things can happen when the wire is heated to 725 degrees. Very likely these were cribbed from somewhere, and that may well have been one of the "high-end" cable sites which are not really reliable sources for this sort of thing. But what I can tell you is that ETP is not known for falling apart, not in the middle and not at solder joints. People have been using it for decades in every sort of communications cabling; I can guarantee you that if it made the least difference in the durability of something horrible to assemble like a multi-pin camera cable, the industry would have insisted upon OFHC a long, long time ago. We never have to get our irons up to 725 degrees F, so if the claim is that ETP might be marginally more fragile after it's been heated to that point, fine -- I don't know that to be untrue -- but I would doubt very much (1) that the people who assemble our HDMI cables ever need to get it that hot (and I've been to the factory in China and watched them solder HDMI connectors, which is very much a "quick-touch, get the solder to flow and move on" kind of operation), and (2) that such an issue accounts for much, if anything, in the way of connection failure.

As I've said in the piece on our site on this subject, if OFHC would make our HDMI cable better, I'd use it. It'd be the easiest possible decision. We already do things that make the cable less convenient to terminate (solid conductors), and more expensive (bonded pairs) -- because those things MATTER to cable performance and quality, and the objective here is not to save money but to make the best HDMI cable that can be made. We did consider silver-plating the signal pairs, which would slightly reduce attenuation, but after doing the math we realized that the improvement was so marginal as to be completely laughable (how much would you pay to add one inch to the working distance?), while at the same time being rather costly. OFHC wouldn't be nearly so costly.

But the cost, sometimes, of ignoring incorrect "conventional wisdom" is getting flamed in the odd review or discussion thread, and this OFHC thing does come up in that way from time to time. When we know that we have lost a sale because of it, we take a deep breath, and we remember that by sticking to the facts on cable quality we have made a good impression on many a broadcast engineer, and that the referral business that flows from that -- the "my next door neighbor is the engineer at the TV station and he says to use Blue Jeans" -- is worth many times what the odd loss of a customer to OFHC dogma is worth. And, because we don't spend our days dreaming up ways to tout OFHC and other inconsequential attributes of our cables, we do sleep well at night.

Kurt
Blue Jeans Cable

KurtBJC

Speedskater wrote: »

Note that Steve Lampen has over 70 blog pages and 2 books on audio/video cabling.

Steve is a good friend of mine; I just spent two days at CES with him, and in 2013 he spent a number of hours helping to represent us at our trade show booth at NAB. He thinks OFHC is nonsense, just as all the other engineers I've talked to do....

He and I have also done a couple of joint presentations to the local AES here.

SCompRacer

Greetings Kurt! Good to meet you on line here.

KurtBJC

Nice to meet you, too! And thanks for the nice testimonial. We have been getting all manner of reports from users of good results with our patch cords, and if we'd had any idea just how awful some of the common products in this market were, we would have gotten into it a long while ago. Interestingly, it has met with a tremendous amount of skepticism -- people have a hard time believing things are really as bad as all that, and I think there is something deceptively simple-looking about eight little wires in a jacket. How hard can that be? But anyone who has dealt with shoving high-frequency signals through balanced feedlines knows that indeed it's a good deal more complicated than just making sure all the wires are hooked up....

Kurt
Blue Jeans Cable

mccarty250

So when performing a data transfer unless you experience packet loss incurring retransmits your transfer speed will not change. When there is packet loss and a TCP acknowledgement is missed a retransmit is incurred after which the TCP window size attribute (basically a number in bytes for how much data can be sent before an acknowledgement is required) is reduced so that more acknowledgements are required. This adds protocol overhead and acts to throttle the transmission. It's easy to figure out if this is occurring, you simply perform the file transfer while running Wireshark (packet capture freeware) on your local machine and then look for retransmits. That would be a potential indicator that your cable is bad.

Sure, I'm sure there is plenty of cable that is out of spec luckily data protocols are resilient and are made to run over diverse infrastructures. Unfortunately as I'm digging into the specs for audio transmission like SPDIF it appears that there is no provision for retransmits i.e. it's an unreliable protocol, no buffering, etc. etc. It's pretty primitive i.e. if you lost data you'd just experience playback missing those bits.

As far as the hostility you're seeing in certain threads yes, people are pretty volatile and religious in their convictions regarding audio it appears. Unfortunately it escalates into being personal very rapidly here.

I like your point about continuing to use gold despite there being superior alternatives due to the frequently regurgitated audio 'common wisdom'. You end up running into folks that know the lingo and sound competent that disseminate information. After it's repeated a few 100 times it becomes 'forum fact' and common wisdom whether it's valid or not. Common phenomenon. Thanks for injecting some sanity.

KurtBJC wrote: »

mccarty250, I saw this thread and thought I'd jump in and comment on this; I'm Kurt Denke, owner of Blue Jeans Cable in Seattle WA, the manufacturer of the patch cord used by SCompRacer.

I agree with you, in principle, but I strongly suspect that the speed difference SCompRacer reports in his file transfer is for real. The surprising thing is that HUGE numbers of patch cords on the market fail their stated spec, and when we tested 20 different so-called Cat 6 and 6a patch cords from a variety of retail vendors on our Fluke DTX certification tester, sixteen failed their stated specs, and eleven of them not only failed their stated spec, but also failed the Cat 5e spec. So, what is happening, in my view, to a lot of users is that they are indeed seeing different performance with different patch cords; this would be inexplicable if we assume that all of the patch cords meet spec, but once we realize that many of them fail it miserably (one "Cat 6" cable we tested failed the 5e return loss spec by 8 dB!), the likelihood of real-world differences in use really does loom large.

My own anecdotal experience -- which I have not generally shared because when you're a vendor people aren't prone to trusting your own testimonials -- is that in running streaming video through our wired home network, patch cords made a huge difference. Using miscellaneous patch cords of unknown origin (we just used whatever was lying around -- until six months ago our company was not really in the Ethernet cable business except in a very marginal way) we had a channel that failed the 5e spec, despite having very high-quality installed runs (Belden 1700A) in the walls. The TDR report on the DTX was very clear: there were massive impedance variations in the patch cords at each end, represented by wildly rising and falling traces, and a long flat segment in the middle representing the installed cable. We replaced the patch cords, had a 10 dB improvement in return loss, and suddenly video which had been quite choppy was continuous and clear. This was not a squint-and-strain-and-try-to-convince-yourself-it's-real difference -- it was dramatic.

People in bulk cable manufacture and in testing -- engineers at Belden and at Fluke -- have told me that patch cords on the consumer market (as well as a good many in the professional market) are quite poor. Fluke, some years back, found an 80% failure rate, which happens to match our result (4 of our 20 sample cables purchased met their stated specs) exactly. When you're pushing word processing documents across a not-so-busy network, of course, this usually just doesn't make a noticeable difference -- but when you're running real-time streams, or moving large files, it certainly can.

Again, I agree with your statement. "nless there is something physically wrong with a cable" data rates should be the same with any two cables of the same type. But getting consistent impedance, and getting the right lay length relationships within the cable to minimize crosstalk, and terminating the cable without creating huge RL or NEXT spikes at the ends, is not as easy as people think, and there are indeed a lot of cables on the market which do have "something physically wrong" with them.

Kurt
Blue Jeans Cable

KurtBJC

I haven't yet taken the time to study the rate of actual packet loss and its relation to the cable quality--the problem, of course, is that when you do that, you get answers which are specific to the scenario you've looked at. Different network cards, hubs, etc, with different tolerances and different quality of data recovery, will yield different results. But the failures we're seeing on conventional mass-market network cable are in many cases quite profound and it's very easy to believe that these are causing sufficient losses to affect network speed.

As a sort of casual experiment in this sort of thing, I decided last night, after swapping out all of our old network patch cords in our theater room, to take them in to work and measure them on the Fluke. There were five of them, in lengths of about 3, 5, 6, 7 and 14 feet; I couldn't remember where any of them in particular had come from, other than to say that none of this was Belden cable stock so we certainly didn't make them -- very likely we had picked them up from office supply stores and whatnot as needed over the years. All were in good physical condition -- no issues like kinking that might contribute to troubles. The results are in this .pdf:

cablesfromtheaterroom.pdf

Four failures and a pass, with some pretty whopping big failures in the mix: a 4.5dB failure of NEXT on the 14 footer, and a 6.1dB failure of NEXT on the 3 footer. And if you think the "pass" is anything special, think again: the margin of the pass was zero, which not surprisingly is within the statistical margin of error of the tester (we don't ship "marginal pass" cables; if we can't be sure it really is a clean "pass," we reterminate). Resilient as the standards may be, when cables start jumping up the crosstalk and return loss by these kinds of margins beyond the spec limits, it's no surprise if networks slow down.

Now, as you say, a lot of signal types are not so resilient. S/PDIF and TOSlink offer no error correction. HDMI is the crazy one -- no error correction, and 6 Gbps to run through each data pair in the cable under the new 2.0 spec. The problem, of course, is that when you're running this stuff uncompressed and real-time, there really isn't any space in the system for error correction unless you can run the data rate significantly faster than the desired throughput.

pitdogg2

Thanks for the detailed info Kurt

SCompRacer

Kurt, are some of these failures attributed to the termination? Basically you have a plastic connector with terminal contacts. A tool presses the contacts through the insulation into the wire. It appears friction between the terminal contact and plastic plug is the only thing that maintains the connection.

I notice you use some different high quality terminations compared to the bubble packed ones I got.

KurtBJC

SCompRacer wrote: »

Kurt, are some of these failures attributed to the termination? Basically you have a plastic connector with terminal contacts. A tool presses the contacts through the insulation into the wire. It appears friction between the terminal contact and plastic plug is the only thing that maintains the connection.

I notice you use some different high quality terminations compared to the bubble packed ones I got.

Termination can cause failures, certainly -- but at Cat 5e if your connectors are close to decent, it's hard to make a really bad termination. It looks as though the terminations on these failing cables were just fine. Take a look at the reports, and you'll notice a table that shows the "HDTDR" results. A TDR is a time-domain reflectometer -- what this shows is the product of the echoes that come down the cable when a pulse is sent, and because the timing of a reflection, given an approximately-known propagation speed, tells you not only the time but also the distance from which a reflection came, a TDR can be used to find impedance variations in a cable. In an ideal cable, the TDR traces should be completely flat. This will not ever be completely the case, because no cable, no matter how well made, has a perfectly consistent impedance throughout. But the deviation of the line from the axis shows how bad the impedance variations are. In a high-quality 6a assembly, where termination is critical, the TDR trace will always show a huge bump (well, huge if you do it wrong, somewhat less huge if you do it right) at each end, where the connectors are, but if the cable is well made the line will be quite flat in between. On these 5e cables from my theater-room pile, you see just the opposite: not such huge deviations at the ends, but lots of warble in between.

In other words, in these cases the termination quality is probably just great -- but the cable quality itself is poor. An engineer at Fluke who I spoke with about some of these patch cord results said that there is more "85 ohm network cable" out there than most people suspect. The impedance of some of the patch cord stocks is badly off, and that means lousy return loss. Not shown on these reports is the HDTDX traces -- these would give some clues as to why the crosstalk was so bad, and my suspicion there is that many of these Chinese cable manufacturers have not really studied the lay length relationships sufficiently--the best way to minimize crosstalk is to vary the lay lengths between pairs, but finding the best set of four lay lengths that will minimize crosstalk is a tricky bit of business.

The connectors we use are from Sentinel in York, PA. They make very nice high-quality connectors, but the basic IDC (Insulation Displacement Connector) idea is the same--metal blades that slice into the conductor ends. Our 6a plug (which we are also using on many, but not all, of our Cat 6 assemblies) is a three-piece connector with a pair separator, a wire "sled," and a plug body. The benefit of this somewhat fiddly design (very inconvenient for "field" termination) is that the distance over which the pairs have to be untwisted is very short, and for crosstalk at 500 MHz, that's critical. Panduit also makes an excellent Cat 6 plug, but it's even more fiddly. But if you just try to use conventional 5e connectors, the cable will fail Cat 6 and 6a all the time--there's just too much untwist required to get the wires lined up. By lining up the wires at the last couple of mm, the Sentinel plug makes it possible to preserve the twist well into the plug body which you cannot do with a conventional one-piece 5e connector.

Kurt
Blue Jeans Cable

SCompRacer

Thanks for the info Kurt! I learnt stuff I didn't know before.

It shows when everything matters, that means everything....

tonyb

Thank you Kurt for your input. I know you get tired of explaining this stuff over and over again, but it's the nature of the beast in audio circles....not just with cables either. Your input is valued and welcomed anytime.

KurtBJC

tonyb wrote: »

Thank you Kurt for your input. I know you get tired of explaining this stuff over and over again...

Thanks, tonyb, and SCompRacer, and everyone else, too. I actually don't get tired of explaining this stuff quite as quickly as most people get tired of listening to it, so I am always happy to find people who are actually interested in knowing....

Kurt
BJC

pitdogg2

KurtBJC wrote: »

Thanks, tonyb, and SCompRacer, and everyone else, too. I actually don't get tired of explaining this stuff quite as quickly as most people get tired of listening to it, so I am always happy to find people who are actually interested in knowing....

Kurt
BJC

Well we are like dry sponges here and we never get tired of learning from those who know. Although I may never be able to repeat any of it, it is nice know that what I came away with is buyer beware as we could be getting chumped by those unscrupulous sellers out there just trying to fleece the sheep with their brickabrack.

Thanks Kurt

Ivan

SCompRacer

I was impressed with the term IDC (Insulation Displacement Connector). Before I just thought of it as just a crimp connector. lol

KurtBJC

Yeah, that's not a term you hear everywhere. It's also referred to as a crimp connector more broadly, but usually when we say "crimp" we're thinking of discrete pin-and-sleeve, three-piece crimp connectors like Canare BNCs. But there's also compression (e.g., Thomas & Betts Snap-n-Seal), solder, weld, and, for multipin connectors like DB25, the picturesquely-named "crimp 'n' poke." There's probably a formal name for that last, but I like "crimp 'n' poke" better anyhow.

There is a surprising amount to know about wire and cable, most of which most people do not exactly find thrilling. Every year I attend what surely, for the non-specialist, must be the most boring trade show imaginable: the Wire Processing Expo in Milwaukee. Nothing but machines and tools for handling wire and connectors.

Kurt
BJC

tonyb

Well heck Kurt, if it's that boring I'm sure many of us would keep you company....buy you a few cocktails and make you laugh your BNC connections off. Let us know in the future, always looking to learn and decipher the marketing fairy dust so prevalent in this industry.

tonyb

KurtBJC wrote: »

There is a surprising amount to know about wire and cable, most of which most people do not exactly find thrilling. Kurt
BJC

Amen to that. Cable talk is about the number one topic to start a brawl. Personally, I could care less if coat hangars are used inside a fancy sleeve, as long as it sounds good to my ears whats inside is irrelevant to me.

Going back to the USB failure rates, I'm curious. Is there no such standard for USB to have to pass ? I mean, if there are, why such a high failure rate ? Are there not independent labs to occasionally check this stuff to make sure it's as advertised and up to spec ? I guess we can say the same for a lot of other things too, eh ?

KurtBJC

tonyb wrote: »

Going back to the USB failure rates, I'm curious. Is there no such standard for USB to have to pass ? I mean, if there are, why such a high failure rate ? Are there not independent labs to occasionally check this stuff to make sure it's as advertised and up to spec ? I guess we can say the same for a lot of other things too, eh ?

It seems to me -- and I should warn that I'm not entirely sure of this, so could be wrong -- that up through USB 2.0 there was no compliance testing requirement for USB devices, cables, etc. Whenever that happens, you get problems; DVI was like that, with a published spec but nobody checking on compliance with the spec. But with USB 3.0 I think there is now a compliance testing requirement. Of course, USB 3.0 cables aren't plug-compatible with 2.0 devices, so that doesn't really help in the 2.0 world.

My impression, having seen a lot of Chinese cable assembly companies at a lot of trade shows, is that there are a lot of people who just do not really care what the spec is. A lot of these companies have rather primitive systems, and once made products that were not very spec-critical. For example, one factory I recall corresponding with had originated as a telephone-wire business. Telephone wire is very easy to make. Twist rates aren't especially critical, impedance isn't especially critical, and so if you've got the ability to insulate wire, twist it and jacket it, you're a telephone wire company. Companies like this will take a look at a coax, or a high-speed data cable, and just copy it, with highly variable results. Most of the customers don't know enough about the product -- and this is true at the importer/wholesaler level, too -- to actually do any independent evaluation of quality, so it goes to market. But what is the impedance of that coax? What's the impedance of those pairs? Are the UL codes printed on the jacket real, or are they fraudulently using some other factory's UL codes? On those subjects, it's pretty much guesswork.

Making a coax, to the uneducated eye, may seem like the easiest thing in the world. So, you've got a wire; it's got insulation over it; it's got a foil wrap and a braid shield, and a jacket. If you and I had an extruder, a braider, and some spools of wire (most cable factories don't draw their own wire), we could make coax with very little setup time. But what could go wrong? Well, lots of things.

(1) The wire: how well was it drawn? How round is it? How well was it annealed? Has it still got lube on it from the wire drawing line? If it was washed, is it now dry? When we pull it over pulleys and into our extruder, is the tension high enough to slightly knock it out of round? Is there any out-of-round or other inconsistency in pulleys that will cause such a change in wire shape to repeat over a regular distance? Tiny, tiny things--but these tiny things matter.
(2) The dielectric: what are we foaming it with? Do we have a foamer with consistent bubble size? As the foamer warms up, or as the dielectric warms up, does it affect the consistency of the bubble size?
(3) The dielectric extrusion: how consistent is the outer diameter of the dielectric? It's being drawn through a die but it's foamy stuff and it expands. How much? How well centered is the wire in the dielectric? If there is a minute amount of lube, or washing fluid, or water, on the wire, is this affecting the dielectric? And, very important for any high-bandwidth cable: do we have in-process monitoring that will detect small changes in the product and correct them on the fly (or, at least, alert the operator)?
(4) The winding of the extruded dielectric onto a production spool: shield application runs much slower than dielectric extrusion, so you've got to collect your "core" on production spools. Wind too tight, and you crush the core together. Wind too loosely or too irregularly, and the core crosses over itself causing bumps and divots. Is the temperature of the material, and hence the final size of the bubbles, still changing at this point?
(5) Shield foil wrapping: your foil can easily fold up while being wound onto the core. How are you going to stop this from happening? The foil should have a shorting fold. Does your foil wrap machine consistently produce that shorting fold, without gaps?
(6) Braiding: tension is important. The coax has got to be fed through the braider at a rate consistent with the application of the braid. And the braider is a clattering nineteenth-century steampunk kind of an affair...do all the parts do what they're supposed to do? And do you have a nineteenth-century steampunk mechanic on hand if they don't?
(7) Jacketing: Ah, this is getting easier. But you do need the jacket to extrude on nicely so that it doesn't infiltrate the braid excessively but does bond to it well enough to keep the insides of the cable from slipping through it as through a tube when somebody goes to terminate the stuff. And the jacket material is critical to your UL rating and NEC rating...

So, you, I, and a buddy or two could knock out some coax if we were left in an abandoned cable factory for a while. But when we stuck some BNCs on the end of it and sweep-tested it, we'd probably see a lot of nice spiky return loss, and we'd probably find that its impedance bore no very close resemblance to whatever we were shooting for. And sure enough, I have seen a few test reports from Chinese coaxes (not a lot; they don't find them useful for bragging!) and that's what we see.

In paired cables, it's the same problem. Process control, impedance, consistency. USB ought to be easy to make, but the factory that can't make four good data pairs for a Cat 5e can't make one good data pair, either. And who's going to test it? Who has both the test gear and an incentive to test? For the vast majority of applications, a USB cable that's "good enough" truly is good enough. I hook the occasional printer up with a USB cable, and it works. Whether USB cables are frequently problematic for audio is something I don't know much about, but when we did look at producing a US-made, bonded-pair cable stock for USB a few years back I know that we came to the conclusion that it had a very, very limited market, mostly because USB has an inherent length limit (so we could not have a cable that works over substantially longer distances than others) imposed by its two-way protocol. Maybe I should revisit that -- but we don't sell a lot of USB cable.

Kurt
Blue Jeans Cable

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I use BJC in both the H/T rig and 2-channel rig and they are superb. Good job folks.