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Blue Jeans Cable Isolation Transformer Review

Rate this isolation transformer:

  • 1. Poor (headless panther)

    Votes: 192 95.5%
  • 2. Not terrible (postman panther)

    Votes: 1 0.5%
  • 3. Fine (happy panther)

    Votes: 1 0.5%
  • 4. Great (golfing panther)

    Votes: 7 3.5%

  • Total voters
    201

Angsty

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Back to the WBC stuff for a bit as to whether their marketing is more a poke at audiophilia or not, more about their pricing. They use good construction, materials and connectors and the value in that respect is very good, the manufacturing location not so much but what's new in consumer products in that respect?
I bought a pair of WBC XLR cables and initially was impressed. Later, I found that the connectors lacked the locking hole needed to secure them from pullout. Even WBC has its missteps.
 

Chrispy

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I bought a pair of WBC XLR cables and initially was impressed. Later, I found that the connectors lacked the locking hole needed to secure them from pullout. Even WBC has its missteps.
So they sent you a different spec connector than advertised? Someone else mentioned much higher prices for some cables than I'd noticed in the past. Maybe they're just jumping on the silly wire train as so many have....
 

RF Air

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I wrote to BJC as well and they responded to me in kind like @Sal1950. The fact that they acknowledge the issue and have attempted to understand the problem is a respectable response to a newly discovered issue. Recognizing that BJC has many customers with different product requirements and budgets, it would be fair to say that the transformer was probably a simple decision to offer a standardized solution, without much consideration or concerns for specification.

My sense is that they are earnest in their concern to resolve the circumstance and will work the issue in a responsible manner. I also believe they are not trying to protect any egos, but merely trying to discover what is wrong and work towards correcting the problem once it can be fully understood and identified. For this response, I still feel loyal towards their business and products.
 

Krusty09

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I bought a pair of WBC XLR cables and initially was impressed. Later, I found that the connectors lacked the locking hole needed to secure them from pullout. Even WBC has its missteps.
It's funny that u posted about the locking hole in that after today I'm a little torn about the hole. I had to move my entire rig as my home is being painted and long an behold the push pin that releases the xlr stopped working out of now where. I have not touch the connector in 5 years and it just stopped working. Not sure how many people have had to deal with this but I can tell ya it's a real pain in ass. With that said it might not be the end of world because if your like me your not moving your stereo or you cables that often so as your cable won't fall out anyway and if do need to move it there is no way it's gonna get stuck in there.

Just thought the timing of this was kinda of funny.
 

JSmith

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Quote by BJC "I know the product has been very well received"
That part isn't right though... reports all around for years referring to audible issues. No one has ever complained to them? I do find that a bit hard to believe... but good to see they're looking into the issue. It's such a small/simple device that the DUT is unlikely to be "broken" and if it was, it likely wouldn't do anything at all. Surely questioning a 40Hz test via an AP is a little off... will be interesting to see how this develops anyway.


JSmith
 

Chrispy

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That part isn't right though... reports all around for years referring to audible issues. No one has ever complained to them? I do find that a bit hard to believe... but good to see they're looking into the issue. It's such a small/simple device that the DUT is unlikely to be "broken" and if it was, it likely wouldn't do anything at all. Surely questioning a 40Hz test via an AP is a little off... will be interesting to see how this develops anyway.


JSmith
Then how many organizations would admit anything these days? More likely to see a marketing standoff/wall.
 

KSTR

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I’ve read your paper on this. Aside from it being -110db, The clear solution is to provide a better SMPS, not go back to the 70s and go linear. There are a plethora of reasons why benchmark (another no BS company) prefers SMPS. Along with many other huge names have gone on record over the clear advantages of SMPS. Oh and I cannot find this RME linear upgrade, would you mind linking it to me?
Release of the RME DPS-2 seems to have stalled for some reason, but you can see pics of a prototype here: https://www.kellerkind-audioforum.at/thread.php?threadid=2502

The point with SMPS is not the quality of the output voltage itself which can be made as good as it gets, rather it is the EMC bridging capacitor which is always present, connecting primary and secondary sides. You can see from below typical schematic that the primary voltage the cap is connected to jumps around like crazy with respect to mains earth because one of input lines, N, will always be close to PE, thus the diodes connecting alternatingly the bottom side or the top side of the reservoir capacitors to PE:
STEVAL_ISA014V1_Schematic.JPG


If you remove/reduce this capacitor (C5 here) the leakage current will be lower and more benign but you won't pass EMC compliance tests. To get there, a lot of bulky and costly additional filtering is required, notably for a floating (2-prong) supply with floating secondary like the typical SMPS power brick or wall-wart. Alternatively, one can cascade with a second (low leakage medical grade) SMPS working on the DC side... costly again.

"70ies tech" -- with a properly spec'd transformer -- is a very viable way to attack the problem by simply avoiding the root cause. It's cheap and very reliable, and it works very well.
 

restorer-john

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Release of the RME DPS-2 seems to have stalled for some reason, but you can see pics of a prototype here: https://www.kellerkind-audioforum.at/thread.php?threadid=2502

The point with SMPS is not the quality of the output voltage itself which can be made as good as it gets, rather it is the EMC bridging capacitor which is always present, connecting primary and secondary sides. You can see from below typical schematic that the primary voltage the cap is connected to jumps around like crazy with respect to mains earth because one of input lines, N, will always be close to PE, thus the diodes connecting alternatingly the bottom side or the top side of the reservoir capacitors to PE:
STEVAL_ISA014V1_Schematic.JPG


If you remove/reduce this capacitor (C5 here) the leakage current will be lower and more benign but you won't pass EMC compliance tests. To get there, a lot of bulky and costly additional filtering is required, notably for a floating (2-prong) supply with floating secondary like the typical SMPS power brick or wall-wart. Alternatively, one can cascade with a second (low leakage medical grade) SMPS working on the DC side... costly again.

"70ies tech" -- with a properly spec'd transformer -- is a very viable way to attack the problem by simply avoiding the root cause. It's cheap and very reliable, and it works very well.

And this has exactly what specifically to do with this review??
 

squared80

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I sent them an email a few days ago, as well. Here was their response.

Hi Mike,

I appreciate you taking the time to bring this to our attention. We've taken a look at this review this week, and are in contact with the manufacturer for guidance. Below is a short response from Kurt:

I was very surprised by the review -- I've had one of these units in my own system for years and have had no problems with it at all. After reading the review I did a series of listening tests with mine, taking the regular speakers out of the system and just feeding the subwoofer, quick-swapping from a direct cable connection to a connection through the transformer. I could hear no difference at all. I then tried this with another subwoofer and, likewise, found no difference at all.

I've written to the transformer company that makes these for us to see if they have any insight. I'm unclear on what the testing setup precisely was, what kind of load was placed on the output, et cetera, so I'm not sure whether the testing was representative of actual use conditions or not. I'll follow up by listen-testing a variety of these drawn from our current inventory, in case there is some difference in quality between batches. There's always the possibility, of course, of a bad unit, but when we've had that arise in the past it's generally been something more like an intermittent connection at one of the RCA jacks. If listening tests fail to reveal anything of interest, I'll follow up with some people I know who can do more in the way of analytical testing.

Right now I don't think we're in a position to tell anyone anything definitive, in large part because I'm not sure anything is actually wrong. I know the product has been very well received and that it is mostly used in home theater systems for subwoofers that are primarily relied on for low-frequency effects. Certainly if anyone asked me what he should use for a high-end audio system, my first reaction would be that you want to try to resolve grounding issues first and foremost, because there will always be some degradation with even the best isolation transformer. Failing that, I'd probably recommend going to Jensen, who make a top-quality product. But I have found this unit great for my own home theater and cannot, even with careful listening and rapid switching between transformer-in and transformer-out condition, hear any impact. We'll see what the transformer people say about it, and go from there.

Kurt,

Blue Jeans Cable
 

solderdude

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A copy from post #146 above.

Damage control, they basically say... it works fine for me and others.

The device is not defective it works exactly as can be expected from them. One should just realize these never will see 2V on it as it is used behind a volume control and sensitivity of those SW is well below 2V levels.
 

Trell

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A copy from post #146 above.

Damage control, they basically say... it works fine for me and others.

The device is not defective it works exactly as can be expected from them. One should just realize these never will see 2V on it as it is used behind a volume control and sensitivity of those SW is well below 2V levels.
And now I think less of that company.
 

CDMC

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Guys, the Iconoclast line is clearly made by Blue Jeans, but its a luxury product for people that want to buy a luxury product. That's why it has it its own separate website. If it performs terribly, then sure, fault them for it. But if it performs well, and just costs a lot extra for gee-whiz, gold-plated, impress your buddies reasons, then there's no problem offering that to people who want to blow their money on it. I sure hope all you guys that are criticizing them for that drive base-model Toyota Corollas, because anything more is a waste of money when a Toyota Corolla will get you from point A to point B perfectly.

I think this is spot on. Blue Jeans and Belden are offering a luxury product for those that wish to buy it. Presumably, they make more profit off of it, which is the general goal of a business, to make a profit. They are not making any outrageous claims, simply offering a luxury item, that unlike most, at least uses quality components and assembly. For some, it it is worth several thousand dollars. For the rest of us, there are products from the same manufacture at less than 10% of the cost with the same quality of assembly, quality of production, and for our purposes, identical performance.

I will note it is interesting the Icononclast speaker cable design sure looks a lot like the classic Kimber Kable designs which can be purchased for between 1/10 and 1/5 the price.
 
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amirm

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The device is not defective it works exactly as can be expected from them. One should just realize these never will see 2V on it as it is used behind a volume control and sensitivity of those SW is well below 2V levels.
At 20 Hz, the box clips at just 0.38 volt:

index.php


So nowhere near 2 volts. Even at 60 Hz it clips at 1.3 volt.

But yes, those people who don't have the issue have likely set their sub sensitivity high, driving it with low output from the AVR. Others who report audible problems, are the other way around. As a minimum then the company needs to specify this constraint.
 

solderdude

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Yep, this behavior can be expected from such small transformers at low frequencies and this one does not disappoint from a measurement p.o.v. in the sense that it does what ist should do... namely saturate at low frequencies (but does disappoint for signal fidelity :) )
This is not measurement error (just look at the scope plots you posted).
The fact that this 'Kurt' does not hear it speaks volumes .... but not at high subbass volumes :D
To leave no doubt ... I voted poor and would not defend nor recommend the product.

Most SW (at max. sensitivity) clip at 0.5V which is just 4dB above 0.38V so can understand that not all users actually hear downsides when they don't always play near max. volume was my point.
No idea how loud Kurt plays though.
 
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Sal1950

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A couple points have encouraged me during the length of this review post.

One is that although the transformer looks to be severely flawed it is a very inexpensive item
and not something that can be considered snake-oil, can't be much money in it for anyone. The
worst I can blame BJC of is not doing their do-diligence and giving the product proper testing.

The other, and the big one for me is their involvement with the Iconoclast cables. Unlike some
earlier times, it now seems that the only mention I can find of the product on their website is
buried deep under "articles" header which I could only find using an outside search engine.
OTOH, they're still riding the fence between a objective "show me" and the subjective BS lines.
Time to go straight Kurt, will you present a verifiable, repeatable, controlled blind listening test
where these expensive cables can be proven to be a audible improvement over the other excellent
cables you build and sell? Or will you continue to support snake-oil sales to the gullible uneducated
with only "listen and decide for yourself" market?

Maybe with a little polite encouragement based on asking for verifiable evidence as is our habit,
we can get that removed also. ;)

We'll see what the outcome of the transformer issue brings.

The fact that this 'Kurt' does not hear it speaks volumes ...
The husband-and-wife team of Kurt and Pam Denke formed Blue Jean Cable in 2002. According to Kurt, the company name originated "when it was just the two of us at the dining room table, as a kind of contrast to what we saw as a lot of pseudo-technical sales talk in the consumer cabling business."
 

solderdude

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BJ cable is a company and thus has to provide for family(ies) so depends on profit made. I assume it is not 2 people at a dining room table anymore.
Possibly the company started with budget priced decent quality cables but the bigger it gets (the more mouths it has to feed) the more profit is needed.

What better way to sell 'premium' quality cables ?
They cost just a tiny bit more to produce and are the real money makers.
It is a free economy and one can sell cables at any price and make up stories around it. As long as it sells and generates enough money the strategy will not change. If it did it would be to generate more money anyway. Cheaper production and/or increased pricing which needs improved BS stories which people will buy like hot cakes.

The vast majority of the better (read more expensive) cable buyers believes the sales pitches and reviews and so there is a substantial market both in the affordable and more expensive price segment.
They would be foolish not to sell snake-oil-ish cables even if it means to depart from the original premise.
I think it would be hard not to run a cable oriented business without losing integrity on 'the performance' and only sell lower profit cables.
 

Sal1950

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BJ cable is a company and thus has to provide for family(ies) so depends on profit made. I assume it is not 2 people at a dining room table anymore.
Possibly the company started with budget priced decent quality cables but the bigger it gets (the more mouths it has to feed) the more profit is needed.
I hear what your saying but there has to be a line.
The same excuses could be used to sell a little drugs on the side, increased profits.
You either have a company based on high integrity or not.
Nordose, AudioQuest and all the others sell some cheaper, less expensive lines too.
That doesn't make them the "good guys" either. ;)
 

elmoe420

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I hear what your saying but there has to be a line.
The same excuses could be used to sell a little drugs on the side, increased profits.
You either have a company based on high integrity or not.
Nordose, AudioQuest and all the others sell some cheaper, less expensive lines too.
That doesn't make them the "good guys" either. ;)

AudioQuest and others make nonsense claims in the marketing materials for all their products, irregardless of whether it is the lowest cost line they offer or the most expensive. BJC makes no such claims, they just sell quality US assembled cables at (subjectively) reasonable prices. That's the difference.

Also, if you weren't aware, there is a 36 page Iconoclast thread you can continue to sharpen your axe in. None of this has anything to do with the product reviewed in this thread.
 

PHD

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The best audio isolation approach which does not yet exist, is active-digital. Input analog signal is converter into hi-res digital on one isolated circuit, then the bitstream is transferred to a second isolated circuit via an optocoupler (this may even support multiple channels at once), then converted back to analog on a second isolated circuit (fed from isolated PSU).
 

Sal1950

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BJC makes no such claims, they just sell quality US assembled cables at (subjectively) reasonable prices. That's the difference.
"One of my great fears going forward is that people will think that we, who have always been a voice for good sense in audio cabling, have had some sort of personality change. I'm here to assure you that while Iconoclast is not in our traditional pricing zone, that's not the case. We've been asked countless times to take on various "high-end" cable products for various people, and we have always said no. It's not that we reject the idea in principle but that we always find ourselves rejecting it in practice. Usually we have just not found the technical case convincing, and sometimes we've found it downright bizarre.

But with Galen's technical papers at hand and with the testimonials of quite a few happy customers, we think that this is the real deal. Our personality will be the same as always. We won't write sonnets about the cable or promise that the bass will be more chocolatey (around 78% cacao content). We'd rather let the product do what it does, and see what people say.. I never tell anybody what he's going to hear. I'm not going to tell anybody that his system will sound better with Iconoclast in it – What I will say is that it's here, we have it, it has the best and most well-attested engineering work done on it by a man who is one of the nation's top experts on electronic communications cabling, and that anybody who would like to have a listen to it ought to do just that. But if somebody tells me that he hears no difference, I'm as ready to accept his word about what he hears as I am to accept anybody else's word on the same subject. "

Same ole, same ole we get from all the snake-oil peddlers when pressured, "use your own ears". Kurt is just doing the Cassius Clay "bob and weave, rope-a-dope" a slight bit better than some others. BS is BS.
Disappointing
Now back to the review at hand.
 
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