Ulrik Poulsen and his Amazing Alpha-Core Cables

Jonathan Scull: How long have you been making cables, Ulrik?

Ulrik Poulsen: It's actually close to three years now...It's a spinoff from other products we make. Actually, Alpha-Core manufactures magnetic cores and various materials and components for transformers...And we have a daughter company called Tortran that manufactures toroidal transformers. Anyway, five years ago we introduced a new product called Laminax. It's a combination of copper and aluminum with various kinds of dielectrics. This is laminated together continuously in various fashions to produce a material that's used as shielding for EMI and RFI in the electronics industry.

We were selling this special material all over the world, as we'd developed a method for combining special types of thin films and metals without using any adhesives at all!

Scull: Ah-hah...

Poulsen: We export this material, and we also developed machines to manufacture it. Then 2½ years ago I developed and patented a cable design of two parallel conductors inside a single sheath. I thought that cable might have applications in various areas of the electrical industry. The thing about it was, it utilized the same technology we use to make the Laminax products. But I didn't find any takers when I showed the cable around, until a friend of mine thought it might just be the cable the world was waiting for—a speaker cable. And his name is Goertz!

Scull: I see...

Poulsen: Yes, he's an accomplished Danish electronics and audio engineer. He told us what characteristics would be required for audio applications, and we manufactured a cable to those specs. We sent it to him for testing, and he was able to show that it totally eliminated the type of distortion that in this country is called high-frequency roll-off.

Scull: That was the original copper cable?

Poulsen: Yes...

Scull: We have the more expensive silver cable, so perhaps you'll tell us about that?

Poulsen: Sure—it's what we call MI Ag II Matched Impedance type. The basic thought behind the development of the entire cable line—silver and copper—was that if you have a characteristic impedance that matches that of the load, you get a better-functioning cable. That's basically transmission-line theory, where you match the impedance of either the load or the source in order to prevent mismatch reflections. That's why for certain applications—television or antenna wiring, for example—you need a 300 ohm or 75 ohm cable. That's the same theory, mostly used at much higher frequencies. But it's also valid at lower frequencies within the audio spectrum. We were able to demonstrate the effects of both the mismatch reflections and the absence of high frequency rolloff reaching well below 10 kilocycles, which is smack in the audible range, of course.

But you asked about the silver cable—that's the same geometry as the original copper cable—a 10-gauge 2.5-ohm characteristic impedance speaker cable. It consists of two solid conductors ¾" wide and 10/1000" thick. Placing those two conductors a mere 3/1000 of an inch apart really drives the inductance way down. At the same time, it raises the capacitance of the cable. And since the characteristic impedance is the square root of the inductance divided by the capacitance, that combination enabled us to reach a characteristic impedance that's in the single-digits. And that is not the case with most other audio cables.

Scull: I wonder if that's why it works so well with the Jadis single-ended amps, which have a typically high output impedance?

Poulsen: Yes, but you see, the output impedance of the amplifier is of no real significance in this case as long as the load impedance is of the same order of magnitude as the characteristic impedance of the cable. It's sufficient if you have an impedance match at only one end of the link. You can compare them if you take an optical point of view. If you have mirrors at both end of the cable, you'd have multiple reflections—you'd be able to see yourself repeated hundreds of times.

Scull: I understand...

Poulsen: If you have just one side with an absorbing characteristic instead of a reflective characteristic, that breaks the chain, and you avoid having those repeated reflections. And that's sufficient—if you have a match on either the load end or the source end.

Scull: Okay, let me carry out my earlier threat and come back to dreaded RFI. Obviously your cable isn't a twisted pair of a type that fights RFI, so...?

Poulsen: Because they have a low inductance, which pulls both ways, the radiated fields of the cable itself are virtually zero. By the same token, it also makes the cables insensitive to outside fields. You can easily test this by bundling the cables with power cords—you don't get any line-frequency hum. And you can bundle them with other signal-carrying cables, and you get no crosstalk whatsoever. You can also easily check that they're impervious to broadcast frequencies, because you can hear that there's no dirt getting into your feedback loop at all.

Scull: As I understood from speaking with you earlier, you were saying that the dielectric of your speaker cable affects break-in time?

Poulsen: Well, Jonathan, there's a few things I personally don't believe in at all. I don't believe in the importance of directionality, and I also don't believe in having a cable sit on full-load for weeks on end before it sounds right.

Scull: It's true your cable sounds just terrific from the get-go, Ulrik. But I have to tell you, I thought you were kidding when you said they required no break-in.

Poulsen: We've looked into this, of course. A lot of people whose opinion I respect believe in running-in cables very thoroughly, but they thought as you did about our cable...

Scull: Well, Ulrik, let me qualify that. In my experience, with some cables it's absolutely necessary—some can take ages to break in.

Poulsen: You're probably right. If that's the case, there's only one explanation I can think of that's physically responsible. I don't think much actually happens to the metal in a cable, but all the organic material that's carried in the dielectric and the insulation may well change during the break-in period. And if that is so, that might explain why our cables break-in so fast. The fact is that in our cable the dielectric is only there in minute amounts. When you have 3/1000" between the conductors, that means that there's only a small, small percentage of the total amount of the dielectric that is active in our cable compared to the amount that's active in other cables.

Scull: Ah-hah. What's the actual material of the dielectric?

Poulsen: It's called polyether terephthalate.

Scull: Oh...sure...that old stuff. Can you spell that for me, Ulrik? [laughter]

Poulsen: Actually, it's not an uncommon material—nothing particularly fancy. The reason we're using it is that it's available in a very thin film, and as I mentioned, we found a very good way of bonding it directly to the metal without using any adhesives.

Scull: But you're not saying how you do that?

Poulsen: [very quickly] No!

Scull: [Laughs.]

Poulsen: This material enables us to have a very high dielectric strength. That means you can apply thousands of volts between the two conductors and yet you won't have any breakthrough.

Scull: That's amazing, just 3/1000" between the conductors...

Poulsen: Actually, 2.4 thousandths, because each layer of insulation that surrounds each conductor is only 1.2 thousandths of an inch thick. Then the whole thing is encased in a common jacket, and for that we are using Lexan, which is a polycarbonate.

Scull: What about some of the electrical properties of the MI Ag? What's the capacitance of the cable?

Poulsen: For the cable you have, it's about one nanofarad [1nF] per foot.

Scull: Of course! You know, that means absolutely nothing to me! [laughs]

Poulsen: Well, it's high compared to other cables, but the inductance, that's the important feature. That's only six nanohenries (6nH) per foot.

Scull: Ahh, yes, nanohenries—I've heard of those!

Poulsen: [laughs.] Yes, we all know about old Henry! [laughs.]

Scull: Ulrik, can you simply state why it's true that low inductance is superior to low capacitance?

Poulsen: Yes: because it's been proven that if you have a high inductance in a high-frequency circuit, it will act as a high-frequency partial short! Yes, it will short out some of the signal components as the signal passes through the cables. And any electrical engineer can make the calculation that high inductance is much more of a problem than high capacitance. The reason that high capacitance has been considered harmful by some is that it can sometimes cause a poorly designed solid-state amplifier to oscillate. If you have a correctly designed amplifier which does not violate the Nyquist rule on the amount of negative feedback you can use, you don't have a problem.

Scull: That's quite a spade lug you supply on the cables. What's its construction?

Poulsen: Yes, it's a solid, almost forged piece of high-quality brass that's rhodium-plated, because rhodium is generally considered to be a better contact material than gold. It's also more wear-resistant. You know, rhodium is from the platinum group—a noble metal—and we consider it far better than gold for audio applications.

Scull: How much are the silver cables retail, Ulrik?

Poulsen: Well, with the silver cables it depends how you buy it. If you purchase a 75' can for professional installation, it's $4668, to be exact. For the typical audiophile who needs 6' terminated, it's $760/pair—a hell of a lot of money for cable. But we know from many of our customers, those who paid $10,000 or $20,000 for their systems, that they just don't want any weak links in the chain.

Scull: What reception has your novel design received in the audio community?

Poulsen: We brought the cable over to Dick Sequerra, who loved it. He A/B'd them with what he was using, and he made a lot of measurements to illustrate the differences. We have a lot of other fans too, like Vince [Bruzzese] at Totem, who also loves the cables. We use his Model 1 speakers in our evaluations, by the way. We know that Thiel also feels that our cable is the right way to go, and then there's Dan D'Agostino at Krell, who has become so enthused that we are now developing a special 7-gauge cable especially for him. It'll be called Krell/Goertz.

Scull: Congratulations. Any last stones to toss?

Poulsen: Laughs Actually, I can talk my head off on the subject, but the proof of the pudding is in the listening.

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JohnnyR's picture

.."We brought the cable over to Dick Sequerra, who loved it. He A/B'd them with what he was using, and he made a lot of measurements to illustrate the differences"

and just WHERE are the measurements? I see NOTHING as usual when Stereophile talks about cables. LOTS of fancy words to impress the gullible but ZERO measurements. Claims of A/B ing but no details at all of how they were done, SBT DBT or just a biased sighted test?

*sigh* nothing new here just the usual BS.

John Atkinson's picture

just WHERE are the measurements?

This is an interview, JohnnyR. You seem to have a mighty big chip on your shoulder :-)

John Atkinson

Editor, Stereophile

JohnnyR's picture

Seems that's all you are good at instead of giving results but that's nothing new for you.I don't expect YOU or Stereophile to ever test cables since that might damage the cash cow of adverts.

DetroitVinylRob's picture

Nice interview, again why I come to Stereophile.

What I think speaks volumes of Stereophile and John Atkinson is that they would chose to allow a public display of criticism of this nature to appear on their website. Obviously, some folks have very decided ideas about the integrity of others, yet seems more than a little misguided, too bad.

Funny too, I would think someone would decide on the value of a product (wire) for listening, by listening... Numbers might offer insight but, tell nothing of what our ears may enjoy IMHO.

Happy Listening!? ;^)>

JohnnyR's picture

The "review" posted above mentioned measurements but not even a link to said measurements nor will we ever see them. If all we need to do is "listen" then why does Stereophile do extensive measurements of speakers, amps and other components but neglect cables, power cords and "tweeks"? Seems they are implying that it's not needed which is hilarious when you read some of the "reviews" that say such things as "There was a day and night differnce in the sound" or " 15 veils were lifted from the music and the soundstage sprung out at me". You get the idea.

 I contend that they aren't tested simply because the results would show ZERO difference 99% of the time with the other 1% being a badly designed product. If Mr Atkinson wishes to disagree, then he will have to do some real testing instead of just "listening". "Listening"  got him into the Synergistic Research magic bowl fiasco a long time ago .Look it up on the forums and make your own conclusions.

John Atkinson's picture

JohnnyR wrote:
The "review" posted above mentioned measurements...

Again for the hard of thinking, JohnnyR, this is not a review. It is an interview.

John Atkinson

Editor, Stereophile

JohnnyR's picture

The so called measuremenst are more than you ever post, even if they are non-exisitant. Grow a pair and do some cable tests with some real measurements if you dare.

DetroitVinylRob's picture

As I see it, reviews are written by reviewers/audiophiles/music lovers and not by scientists, If someone is looking for pure science, maybe, one is looking in the wrong place. Wire seems to be one of the least understood and therefore, most contentious of issues. I know of no one in the audio industry that completely and thoughly has mastered documenting the relative science (in numbers) of what we hear in wire differences and those with proprietary knowledge have every reason not to publish it. Furthermore, it appears to be Dick Sequerra's findings, not John's. Just my opinion.

JohnnyR's picture

......bogus. If the review makes a big deal of their product being measureed and comapred but fail to show any results then why bring it up at all other than for the "gee whiz" factor?

I do agree that looking for science or a ratioanl test here is pretty much like waiting to see pigs fly.

Wire is the least understood????????????? I suppose for the gullible they are when they include a hefty price tag along with "exotic" material like........metal. A wire will have measureable inductance, resistance and capacitance and that's it. It's job is to transfer a signal from Point A to Point B WITHOUT altering the signal what so ever. If it "improves" or changes the sound , then it's a poorly designed product or the reviewer has been fooled with sight bias or the well known comb filter affect where his head has moved during the testing of two components,

Since no one wants to do DBT of cables, then yes of course people will always hear a difference in cables when they know which is which being listened to. Mr Atkinson COULD do such tests but refuses to do so based upon????? I have already stated my theory of why he doesn't but allows "golly that sounded lots better" reviews. Money makes the world go round and pays the rent.

DetroitVinylRob's picture

bogus? gullible? oh really? You find conspiracy, dishonesty, and ignorance wherever you go... sounds like a piss poor way to live.

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