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Product Review
 

Blue Jeans 1694A/7710A Component Video Cables

March, 2005

John E. Johnson, Jr.

 

Click on Photo Above to See a Larger Version

Specifications:

 

● Conductors: Belden 1694A Solid-Core
    Copper

● Dielectric: Polyethylene Foam

● Dual-Layered Foil and Tinned Copper
    Braid

● Connectors: Canare RCA (BNC also
    Available)

● MSRP: $69 USA for 26 Feet (8 Meters)
    Set as Reviewed

 

Blue Jeans Cable

www.bluejeanscable.com

Introduction

Shopping on the Internet is a wonderful experience, mostly because you can get just about anything out there.

Many companies, whose products are mostly sold by dealers, offer at least one or two models from their lines on various websites.

Hi-Fi cables are no exception, and a number of companies have sprung up, not only offering all of their products for sale on-line, but for sale only on-line.

This is a tremendous thing for consumers because the products are less expensive through a direct sale from the manufacturer to us.

Blue Jeans

Blue Jeans Cable is one of these companies. I saw them discussed quite a bit in our forum, so I decided to get some for evaluation.

After communicating with Blue Jeans' Sales Department, I decided on a set of their component video cables. There are several choices here, and the product for review was a set that consisted of three Belden 1694A solid core conductor cables, grouped together, which is their product number 7710A when they are ordered with a wrap that holds them together (in other words, you would order one 7710A which consists of three 1694A cables with a wrap). My particular set came without any surrounding wrap (so the order would be for three 1694A cables), and that gave me more flexibility in running the cables in tighter spaces (it is also less expensive). In fact, I spread them out side-by-side under the rug, which produced a much smaller hump than would have been the case if they were held together in a bundle by the wrap, so you should consider this when ordering them.

The connectors are Canare, which is a very solid plug, much more so than typical connectors. Also, I believe that the plug and jack are more responsible for electrical performance than we have given them credit for in the past, so solid plugs are very important to me. In spite of such high quality construction, the set is still rather inexpensive, especially as the length increases (our projector is across the room from the equipment rack, so we need long video cables).

What Blue Jeans Says

Following is part of a conversation I had with Kurt Denke, from Blue Jeans Cable, about the Belden 1694A conductors:

This was really our first leading product when we entered the home theater cable market; we (my wife Pam and I) were becoming interested in video cabling and I had something of an electronics background, being a ham radio operator since the 1970s, so I was familiar with transmission line theory, which is sort of "what it's all about" video-cable-wise. We were attracted to the Belden 1694A cable because it's the leading product of Belden's relatively new series of what it calls "precision video cables."

These cables (the principal series of which include 1505A and 1855A, and the gigantic 7731A) were developed to serve the professional video industry, in the face of the rise of SDI (Serial Digital Video) as the dominant standard for HD production and editing. SDI signals have enormous bandwidth, and, for reasons which are probably more boring than instructive, that means that cables carrying SDI over distance need to have particularly tight impedance tolerance - which is to say, since no video cable can be manufactured always and exactly to 75 ohm impedance, the "margin of error" within which the impedance of the manufactured cable may vary. The specified impedance tolerance of 1694A is +/- 1.5 ohms, but in practice, the product rarely wanders more than about 1/2 ohm off of the 75 ohm standard.

The importance of consistent and accurate impedance increases dramatically with distance, so with so many people running cable across theater rooms, distributing signals around their homes, and the like, the need for a product like this, cut and configured for home installation, grew. At very short distances, impedance doesn't matter much; but what is a "short" distance keeps getting more restrictive, because HD component signals have quite a bit more bandwidth than standard definition signals, and the higher the frequencies involved, the shorter the wavelength of the signal, and the shorter the wavelength, the shorter a cable needs to be for impedance not to be a factor. At 35 MHz, and with a cable at 83% velocity like 1694A, one reaches a quarter-wavelength, at 35 MHz, at about six feet.

What we've found, in talking to people about cable quality, is that impedance consistency is something that doesn't get talked about much, but it's the most important attribute of an HD video cable. Not much signal is lost to resistance in a video cable of reasonable length, but quite a bit of signal quality can be lost to cable being out-of-impedance. With a bad impedance mismatch, a portion of the signal will reflect back and forth in the cable rather than being delivered to the display on time; this can result in ghosting or ringing, and the longer the cable, the more prominent the effect. Exotic materials and construction techniques have no particular bearing on this; the only thing that'll control impedance well is to have very tight manufacturing tolerances, because impedance depends on physical dimensions: how thick is the center conductor? Does its thickness change from point to point, and how much? How thick, and how consistent, is the dielectric? ...and so on.

Traditionally, the best way to control impedance tightly was to use a solid polyethylene dielectric; older analog video cables like Belden 8281 represent that approach. But there are some problems associated with solid PE. First, solid PE is rather thick and heavy. 8281, though an RG-59 type cable, is larger than a modern RG-6, and much stiffer. Second, because solid PE isn't a very good dielectric as compared to air, one can't make the center conductor, even in a rather big cable, very large.  Third, solid PE cables invariably wind up with higher capacitance than comparable foam PE cables.

What Belden did in this generation of video cables was to work hard on the problem of dielectric foaming. Most modern video cables use a foam polyethylene dielectric, but foam PE has disadvantages of its own. In general, it offers much poorer crush resistance than solid PE, and because it's hard to make bubbles perfectly consistent in size and distribute them with perfect evenness throughout the dielectric, it's harder to control impedance. Belden's HDPE (high-density polyethylene) foam, used in 1694A, resolves those problems with a highly consistent bubble size and distribution, and because the bubbles also have high physical integrity, excellent crush resistance. Consequently, Belden can build this cable with the advantages of a solid PE cable -tight impedance tolerance and high crush resistance - while also carrying the advantages of a foam dielectric - light weight, high flexibility, and lower dielectric constant (allowing a larger center conductor for a given cable size).

The shielding on the 1694A is also top-notch; with a 95% coverage copper braid and a double-sided, overlapped foil, the shield effectiveness of 1694A exceeds that of a quad-shield cable at all frequencies. There's an article about this on our site at: http://www.bluejeanscable.com/articles/shielding.htm.

This cable has now become the top-selling SDI video cable - it's widely used in professional installations where long runs of high-bandwidth signals are required. In fact, its principal competition comes not from other manufacturers, but from other cables in the same family like 1505A and 1855A, both of which are significantly smaller; as you can imagine, if you're running a hundred cables in a tray, size starts to become an enormous consideration, and the manufacturing consistency of the Belden product is so good that the miniature versions perform just as well as the large versions, in SDI applications, unless particularly long runs are involved.

Our whole approach in selling cable has been to turn to the professional market, where specs are tighter than in consumer-market product, and where pricing is very competitive, and try to identify products which would translate well to the home environment. 1694A is just a great cable; it's usable in a variety of applications, and it's economical as well.

As for the connectors - you're probably amply familiar with the Canare plugs, as there are quite a few people using them. One thing I do try to mention to people is that, contrary to some of what's been written about the Canare plugs, there really is no such thing as a true 75 ohm RCA plug; it's impossible to do because the physical dimensions of the RCA connector don't allow it. However, the Canare design is really quite impressive in making the RCA as compatible with a 75 ohm impedance line as possible, by carrying the departure from 75 ohms as close to the end of the plug as can be. There's another article on our site on that subject: http://www.bluejeanscable.com/articles/75ohmrca.htm.

In Use

I tested the Blue Jeans cables with a Denon DVD-5900 player, Kaleidescape Media Server, and Sony 10-HT digital projector.

First, the Canare plugs are very nice, as they hold the connection tightly. I have had some trouble in the past with video cables coming loose from RCA video jacks, and this did not occur here. A loose connection can result in strange video artifacts (ghost images). An impedance issue is probably the culprit here.

The cables are rather stiff, but that is because of the solid core conductor. I prefer this construction though, as I have experienced connectors breaking off from stranded core cables which are less sturdy at the solder joint. Of course, I treat cables a little rougher than a typical consumer who will leave them alone once they are in place, but this does speak to the overall durability of the two different designs.

Video quality with the player and Kaleidescape server was excellent. I switched the cables back and forth between sources, with some tugging on the junctions at the projector, and the connections always remained tight and solid.

There did not seem to be any video noise induced by the long cables.

On the Bench

LCR measurement results were as follows:

Capacitance was lower than most of the other cables we have tested, at 17 pico-Farads/foot, while Inductance was about in the middle, at 0.11 micro-Henries/Foot. Resistance measured 9.7 milli-Ohms/Foot. Here is the table for all cable test results.

So, the bench test results are very good.

I was also impressed by the fact that I requested 8 meter length, and they measured exactly that length. I have ordered long cables in the past that have been off by as much as a foot or more. I like a company that pays attention to all the details.

Lastly, read Kurt Denke's comments about his products. It is very obvious he knows what he is doing, and that inspires consumer confidence.

Conclusions

The Blue Jeans Cable Component Video set appears to be above average both in terms of build quality and LCR test results. They are competitively priced (in fact, lower priced than many), and I have no reservations in recommending them highly.



- John E. Johnson, Jr. -

Copyright 2005 Secrets of Home Theater & High Fidelity

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