Litz Wire for Audiophiles: What Stereophile Is Really Arguing About

"The best-sounding cables I have heard," wrote Jason Victor Serinus about Cardas Clear in Stereophile, and those words became one of the most quoted phrases in the world of audio cables over the past decade. Two one-meter speaker jumpers of Cardas Clear Rev.1 cost $4,085. Their older sibling, Cardas Clear Beyond, starts at $6,500 for a one-meter pair of interconnects and at $25,000 for a full loom. Among collectors, a Nordost Odin 2 set can go for a six-figure sum. Herb Reichert, in the same Stereophile, writes that "the cows in the next valley came running to hear the intensity of Callas's voice when I put in the Clear Beyond." Serious person, serious magazine, serious money.

What exactly are they listening to? And what is inside these cables that justifies the gap between one hundred and twenty dollars a meter for Kimber PBJ and almost fifteen thousand for a Stealth Dream Petite V16?

The answer that audiophile forums dislike discussing is short: inside expensive audio cables there is, most often, litz wire — a high-frequency conductor made of many insulated thin copper strands, transposed so that each one successively occupies every position in the bundle cross-section. The same wire is made in industrial plants for transformers, induction heaters and electric-vehicle motors. The difference is that in one case it is braided with a golden thread and placed in a polished $300 WBT-0114 connector, and in the other it is hidden inside a polyethylene jacket and handed to a plant engineer for the price of a few dollars a meter.

This article is about what actually happens to the signal in a wire, why it matters, and at what point a sensible music lover with a fine ear and common sense can step away from the cult of brands.

1. The cultural context: where the price comes from

An audio cable is a rare case in engineering where science and myth live in the same enclosure.

On one side, there is real science. Bell Labs has studied how a signal travels through a wire since the 1930s. The patents of Cardas, Nordost and AudioQuest contain truthful, verifiable physical descriptions: stranding geometry, the capacitive coupling between pairs, the transmission factor of a leather dielectric versus PTFE. All of this is genuine. Herb Reichert, Michael Fremer, John Atkinson — editors who have spent a lifetime with equipment and written thousands of articles — are not making things up when they say that Cardas Clear gives "two or three extra bass notes on the organ pedal."

On the other side, there is culture. The audio hobby long ago became a ritual: careful selection, long listening, the search for "your own" sound. This ritual has a priestly layer — people who assemble a loom from $60,000 Nordost Valhalla 2 and listen to it in a $500,000 room finished with acoustic panels. And like any ritual, it accretes mythology. Words start to appear: "silver aura," "silky midrange," "airy highs." People start to tell brands apart by "house sound" — the American Cardas is "warm," the Scandinavian Nordost "cold and precise," the British Chord "musical." Within this culture, another way of spending money is born: not for the physics, but for belonging.

Steve Huff, one of the most respected audio reviewers, writes honestly on his blog: "I listened to a $25,000 Nordost; it just didn't synergize with my system — it left me cold." Do you see? $25,000 is a pair of speaker cables. The price of a good car. And the same Huff, giving Cardas its due, admits: "On Audiogon I bought a $1,200 cable that the seller touted as a victory over its $8,000 siblings. Burn-in, listening — it turned out to be about on a par with ordinary $500 cables. Returned it."

Behind this scene is a simple economic reality. An expensive audio cable is construction plus mythology plus distribution plus the retailer's margin plus marketing. The wire inside it, if you break it down into parts (which DIY enthusiasts on the Head-Fi and DIYAudio forums have been doing for twenty years straight), costs tens of dollars. Sometimes hundreds, if it contains silver or single-crystal copper. But almost never thousands.

So what makes those thousands worthwhile?

2. The physics that marketing cannot repeal

Let us start with the fact that a cable really does change the sound. This is not a myth. Two reviewers in Stereophile, sitting across from each other, can hear the difference between a $157 Kimber 4PR and a $4,085 Cardas Clear, and this is not a mass hallucination. The difference objectively exists. The question is what exactly creates it and how reasonable it is to price that.

2.1 The skin effect at audio frequencies

The human ear hears from 20 Hz to 20 kHz. In the highest-frequency part of this range there is a phenomenon that engineers call the skin effect. Alternating current in a conductor tends to flow closer to the surface, leaving the center of the strand underused. At 20 kHz the skin depth in copper is about 0.46 mm. This means that if the conductor of your speaker cable is thicker than a millimeter — and in an ordinary "copper" speaker cable it is exactly 2–3 mm — then the high frequencies travel through the outer ring zone, while the center of the wire does nothing.

This effect is small. At 20 kHz and a five-meter cable length it changes the resistance by some five to ten percent. But it is precisely in this region that the airy harmonics of cymbals live, the breath of a flute, the decay of a grand piano, the spatial hints of an acoustic stage. Musicians and recording engineers know that those five to ten percent hold what separates a recording from a concert.

2.2 The proximity effect between pairs

When out-of-phase currents flow through neighboring strands of a cable, they induce magnetic fields on one another. These fields push the current out of some parts of the cross-section and crowd it into others. The phenomenon is called the proximity effect. Together with the skin effect, the two produce what in audiophile literature is described as "uneven sound in the treble region," "harshness on the violin," "dryness in the highs."

Sound cable geometry weakens these effects. That is why Kimber braids its 4PR from four pairs of black and brown conductors — so that each strand spends part of the time outside the bundle and part inside, averaging out its behavior. That is why Cardas carefully selects the strand cross-sections in a set according to the golden ratio. That is why Nordost has its famous Dual-Mono-Filament: an empty space around the conductor, creating a dielectric air layer.

All of these solutions are working engineering. They really do reduce losses and distortion.

2.3 The ultimate solution: transposition

There is, however, a far more effective way to suppress both the skin effect and the proximity effect at once. It has been known since the time of Karl Ferdinand Braun (the same man whose name is on the cathode-ray tube) and was patented by him in 1910.

The idea is simple: take many thin copper strands, insulate each with enamel, and twist them in a special pattern in which each strand alternately ends up now in the center of the bundle, now on the outside. In such a wire no strand stays permanently in a "bad" or a "good" position — they all work evenly. The current divides equally among them. The skin effect disappears up to the frequencies at which an individual strand itself becomes "thick" — and if you take a 0.1 mm strand, that boundary moves out to several megahertz, far beyond the range of hearing.

This wire is called litz wire — from the German Litzendraht, "braided wire." It solves the HF-loss problem radically. Not by five to ten percent, like the sound geometry of an ordinary cable, but by tens of times, down to the theoretical limit. The physics here is rock-solid, verified and described in IEEE Transactions on Power Electronics in hundreds of papers. We covered the basic physics and a rigorous derivation through Maxwell's equations and Dowell's formula in a long article on the skin effect and the proximity effect.

The only question is who has it inside.

Marketing description link Physical parameter

Click any chip on the left to see which physical parameters create that description. For example, "airy highs" is a combination of low R_AC at 20 kHz (litz wire) and symmetric geometry (suppression of the proximity effect). Both are measurable engineering parameters, not metaphors.

A translation dictionary between audiophile jargon and measurable physics. On the left are six descriptions that Stereophile and Hi-Fi News use in reviews. On the right are five physical parameters responsible for those descriptions. The links are built from the work of Cardas and Nordost and from IEEE publications on cable losses. The point: none of the "magic" properties of an expensive cable need any magic — each one has a number, a dB or a percentage.

3. Litz wire in audio cables: what is actually inside

If you sort the high-end audio cable market by what is physically inside, you get a curious picture. And, to jump ahead, something even more curious: the very fact of a thin litz construction comes with a free side bonus that the audio industry is shy about saying out loud, because they would rather sell a separate markup in its place. We will come back to this in section 4.1. For now, let us look at which of the major players actually use transposed wire and which merely rely on the complex geometry of thick conductors.

Audio Note UK Lexus (United Kingdom). The manufacturer's brochure and the 2024 Part-Time Audiophile reviews state plainly: this is Audio Note UK's first true Litz construction, vital to the operation of the flagship AN-E, AN-J and AN-K loudspeakers. Hand-drawn silver litz wire. Price per meter — from £200, that is about $250.

Cardas Audio Clear Beyond and Clear Light (USA, Oregon, headquartered in Bandon). A patented geometry based on the golden ratio, a hexagonal lay of strands in concentric layers — a construction close to litz wire in principle, although Cardas itself avoids the word "Litz" in its marketing and uses the term "Matched Propagation." Many parallel insulated strands, distributed so that each alternately ends up at different distances from the center of the bundle — exactly the same physical logic as classic transposition. George Cardas, the legendary founder, worked at Bell Labs before audio. Prices — from $1,000 to $13,000 per pair.

Kimber Kable Select KS-6068 (USA, Utah). Silver litz wire, an eight-conductor construction with a patented braiding geometry. The top of the flagship line. $6,000 per pair.

Stealth Audio Cables Dream Petite V16 (USA, San Francisco). Helium sealing of a hollow central tube, 12 strand bundles of 8 individually insulated single-crystal conductors in a patented non-resonant distributed LITZ configuration — that is, it is literally litz wire, and the manufacturer calls it that in the spec sheet itself. Copper of 99.99% purity and 99.997% silver coexist in one bundle. Price — from $14,700 per pair.

Nordost Valhalla 2, Odin 2 (Iceland). Here it is pure silver-plated copper solid core with a Dual-Mono-Filament dielectric. Not litz wire. But the price runs up to $60,000 for a loom.

Kimber 4PR ($157 for 3 meters, Stereophile's budget icon). Eight stranded conductors in a Teflon jacket, braided. Not litz wire in the strict sense — the strands inside are not transposed by the rules of transposition, they are simply braided together.

AudioQuest Rocket series ($600–$2,500). Solid-core conductors using Solid Core Perfect Surface Copper technology. Also not litz wire.

The result is an amusing thing. Those cables where the physics works radically (Audio Note Lexus, Cardas Clear Beyond, Kimber KS-6068, Stealth Dream Petite V16) do indeed contain litz wire. The fact that their makers spent years developing the stranding geometry, selecting enamels and calculating impedances deserves respect and, perhaps, part of the stated price.

But a significant part of the premium market — Nordost, high-end AudioQuest, all manner of "flagship cables with silver solid cores" — is not litz wire. These are single- or few-conductor constructions with clever geometry, beautiful insulation and a brand premium. They work, they sound — but physically they suppress the skin effect and the proximity effect worse than a plain industrial transposed wire built to a cable-production TU specification.

Kimber 4PR 3m pair · braided

$157

AudioQuest Rocket 44 2m pair · solid core

$600

Audio Note Lexus 1m IC · silver litz

$350

Cardas Clear Light 2m pair · litz-like

$1,200

Kimber Select KS-6068 2m pair · Ag litz

$6,000

Cardas Clear Beyond 2m pair · "Matched Propagation"

$6,500

Stealth Dream Petite V16 2m IC · He litz

$14,700

Nordost Odin 2 full loom · solid core Ag

$60,000

---

— for comparison, industrial litz wire —

Diada Литц хА + Neutrik 3m pair DIY

₽10,000 ≈ $110

Materials (copper, Ag, insulation, connectors) Assembly, QC, hand work Brand, distribution, marketing

Cost estimates based on open sources: teardowns by DIY enthusiasts on Head-Fi and DIYAudio, the cost of silver conductor by LME, anonymous comments from engineers at specialized manufacturers, and standard markup distribution coefficients in premium audio electronics. The more expensive the cable, the larger the share of the price that goes not to the physical wire but to marketing and distribution. For the Nordost Odin 2 it is 90% brand. For industrial litz wire it is 65% materials. The physics is the same. Hover over the segments to see the absolute numbers.

And this is where it gets interesting.

4. Diada's industrial litz wire for audio

At Diada we have been making continuously transposed litz wire for industrial applications for six years — transformers, induction heaters, electric-vehicle motors. Our wire conforms to TU DSGT.685660.019 and is made to the same physics described in Braun's 1910 patents and in IEEE TPE today.

4.1 A side bonus: guaranteed copper purity

Before discussing specific grades, it is worth unpacking one manufacturing fact that the audiophile industry carefully monetizes, while we get it for free — simply by the way litz-wire production itself is set up.

In the world of high-end audio, a huge part of the marketing is built around copper purity. You have surely seen these acronyms in the catalogs of Cardas, AudioQuest and Furutech: OFC (Oxygen-Free Copper, less than ten parts per million of oxygen), 4N (four nines, 99.99% copper), 5N, 6N, PCOCC (Pure Copper by Ohno Continuous Casting), LGC (Long Grain Copper). Each new purity step multiplies the cable's price. AudioQuest Tree with six-nines copper costs four times more than the company's base series. The argument sounds lofty: fewer oxides at the grain boundaries, a more uniform crystal lattice, a cleaner path for the electron.

And now, one simple thing the audiophile industry does not like to recall. A thin copper strand — the kind from which any litz wire is braided — physically cannot be made from dirty copper.

This is not a nice turn of phrase. It is harsh manufacturing reality. Copper rod arrives at the drawing machine as an eight-millimeter-diameter bar, and from there it is reduced through dozens of passes through dies down to a thousandth of that diameter. Every microscopic impurity, every oxide, every recycled-stock inclusion becomes a stress concentrator — and when the diameter drops below half a millimeter, these concentrators tear the material to shreds. The drawing machine stalls on breaks, and every stop is money, time and a missed shift. That is why, at any serious cable plant, only metallurgical-grade prime stock serves as the input copper for thin wire.

The Russian standard spells this out in plain text. Under GOST R 53803-2010, copper rod is divided into three grades:

• КМ (М001 copper) — ordinary, from primary electrolytic cathodes. Pure, fresh, straight from refining.
• КМб (М001б, М0б copper) — oxygen-free. Also primary, but separately selected and processed in an inert atmosphere so that practically no oxygen remains in it.
• КМор (М1ор copper) — continuously cast, remelted from secondary copper, from scrap, from refined waste. Several times cheaper than the first two.

You might think the electrical conductivity of КМор is the same on paper. At the same cross-section, a meter of power cable carries exactly the same wattage. But try drawing a wire thinner than 0.5 mm from КМор and everything breaks. Reference materials from NTCM (New Technologies of Non-Ferrous Metallurgy) on GOST R 53803-2010 put it bluntly: "this is critically important for the production of thin wire of 0.15–0.5 mm cross-section, where breaks on drawing machines lead to substantial losses." Translated from metallurgese into plain language — thin enamelled wire cannot be made from secondary copper. Full stop.

At Diada we feel this constraint from the other side of the production chain. We do not melt copper or draw enamelled wire ourselves — that is done by our suppliers with their drawing machines and enamelling lines. Finished enamelled wire arrives at us already as reels of thin strands of 0.071, 0.1, 0.15, 0.2, 0.25, 0.315 millimeters, and on our stranding machines these strands become continuously transposed litz wire. All of these diameters lie far below the magic half-millimeter boundary. That means our enamelled-wire suppliers physically cannot slip us КМор rod — they simply could not produce the gauge we need from it. In our product, secondary copper is cut off not by paper, not by a certificate, not by a marketing promise, but technologically, by the very nature of the process.

For especially thin strands of 0.05–0.071 millimeters the picture is even stricter — there the input is 4N-purity rod (99.99% copper) from specialized suppliers such as Nornickel, UMMC or the Kyshtym Copper Electrolytic Plant. This is no longer just primary copper, it is primary copper of the highest electrical grade — a close sibling of the very "Long Grain Copper" with which AudioQuest paints its price tag.

What this means for the music lover. When you buy litz wire, you are already getting copper no worse than OFC, and more often 4N. There is no need to pay extra for pretty acronyms on the spec sheet: the purity is already built into the product at the level of the technology itself. Hold litz wire with a 0.1 mm strand in your hands — that means the copper in it is primary, because otherwise it simply could not have been produced. But a budget "audiophile cable" with a 2.5 mm² solid core and declared OFC copper is another story entirely. At such a thick cross-section the drawing machine handles КМор rod, and recycled-stock additions, with ease, and no spec sheet will say a word about it. For such a cable to actually contain primary copper, the manufacturer has to deliberately put it there — and all you can do is trust them. With litz wire you do not need to trust anyone: the physics of drawing has decided it for you.

4.2 Three grades for audio

For audio applications, three options from our catalog of 52 grades are especially interesting.

Литц фПЭ — litz wire with a PTFE film over the strands and an outer extruded polyethylene jacket. Formally, it is the only construction in our catalog with a sealed, moisture-proof jacket. In terms of properties, it is a full analog of what Cardas calls a "Propagation Jacket": a dense, transparent tube around a stranded transposed bundle. Good mechanics, the sensible price of an industrial wire.

Литц ПИ — litz wire in a polyimide jacket. Polyimide is the famous Kapton from DuPont, used by NASA in solar sails and by DuPont in the magnet wire of inverter motors. In audio cables, polyimide gives practically zero dielectric absorption and one of the lowest loss tangents. The same physics that lets Kapton work at −269 °C in liquid helium also makes it one of the best dielectrics for the audible range.

Литц оА2 and Литц хА — litz wire in a serving or braid of Arselon, a Russian meta-aramid fiber, a full analog of the American Nomex. Arselon is a fiber braided around the strand, golden in color, outwardly very similar to those "old French" servings on vintage Western Electric and Quad amplifiers from the 1950s. It is precisely this aesthetic of a braided metallic wire — the very "silver aura" that Herb Reichert described for the silver Kimber Kable in Gramophone Dreams: "a kind of glow, like the shimmering harmonic halo of an analog signal." Arselon is not silver but copper — yet the visual culture is the same: braided, retro, noble.

One of our grades — Литц 150×0,1 хА — is 150 copper strands of 0.1 mm diameter, stranded by the rule of five, in a golden braided Arselon serving. The copper cross-section is 1.18 mm² (a little more than 16 AWG). At twenty kilohertz the R_AC/R_DC ratio of this wire is 1.02 — that is, the high frequencies pass with practically no loss. For comparison: for an ordinary 2.5 mm² copper solid core at the same twenty kilohertz, R_AC/R_DC is about 1.15–1.25. You can check these figures for your own geometry in our litz-wire winding calculator.

The cost of our litz wire is on the order of a few dollars per meter (it depends on the specific grade, cross-section and jacket; the exact price is agreed at the order stage). For a standard 3-meter pair of speaker cable that is about $15 for the wire itself. Adding quality connectors — Neutrik, Furutech or Kimber Ultraplate class — a finished pair comes together for $55 to $165 depending on the choice of connectors. A hundred to a thousand times cheaper than a one-meter pair of Cardas Clear Beyond — depending on your length and exactly which Cardas you compare against. The physics is the same.

The difference is in the wrapping, the reputation, the distribution and the ritual.

5. Cultural honesty and a sensible choice

I am not suggesting anyone drop Cardas or sell their Nordost. Everyone has their own relationship with the ritual, and an expensive cable in an expensive system is part of a large aesthetic work that cannot be judged by hertz and decibels alone.

But for the person who looks at the prices in Stereophile with a degree of bewilderment and wants to hear the physics at its own price, there is a choice that is rarely discussed in the magazines.

Buy a ready-made high-end cable with litz wire inside. Audio Note Lexus, Cardas Clear Light, Kimber KS-6068, Stealth Dream Petite V16 are honest products with physics that works. They are expensive, but they deliver what you pay for.

Buy a budget cable without litz wire. Kimber 4PR, AudioQuest Type 4, Van den Hul D-352 are good wires at reasonable prices, but physically they suppress HF losses worse than transposed litz.

Take industrial litz wire and build the cable yourself or through a DIY workshop. This is what tens of thousands of audiophiles have been doing on the Head-Fi and DIYAudio forums for the last twenty years — and many of them get sound indistinguishable from their four-thousand-dollar siblings. You need the wire, you need quality Neutrik or Furutech connectors, you need skillful termination. And a little patience.

If you choose the third path, here is what we offer at Diada:

• Литц фПЭ in a sealed polyethylene jacket — for interconnects and speaker cables with a transparent, slightly warm presentation.
• Литц ПИ in Kapton polyimide — for the most neutral HF transmission, for digital connections and AES/EBU.
• Литц хА in a braided Arselon serving — for lovers of retro aesthetics and a warm, "French" presentation.

The cost of the wire itself is on the order of a few dollars per meter; the exact cost is agreed for a specific construction, cross-section and jacket. For a 3-meter pair of speaker cables as a finished assembly with quality connectors (Neutrik, Furutech, WBT) and our termination with silver-bearing solder — roughly $55–165 in total. For that sum you get a wire in which the physics works at the very limit of what is possible at all with copper and enamel.

5.1 If you don't know how to solder it — we will solder it

Litz wire has one feature that DIY beginners discover only with the iron already in hand: it is not a solid core. A hundred thin strands in enamel require special termination. An ordinary flux and a 60-watt iron will not do here.

Proper termination of class F litz wire (self-tinning enamel) is a quick dip of the end of the bundle into a solder bath at 380–400 °C. The enamel thermally vaporizes and the fresh copper wets immediately. For class 200 (polyamide-imide enamel, which does not tin) it is either laser cleaning or careful friction stripping. Neither can be done properly on a kitchen table with an ordinary iron: either the enamel on some strands remains unburned (and those strands are not electrically connected — the physics of transposition is broken, and one channel sounds duller), or the opposite — the strands overheat and the insulation inside the bundle runs.

So — if you order litz wire from us for an audio project and do not want to risk the termination, we will solder the ends to fit your connectors. The service works like this:

• You send, along with the order, the exact cable length and the type of connectors (Neutrik NL2, Furutech FP-201G, WBT-0144, banana plugs, spades — any standard ones). You send or bring the connectors yourself — we do not stock branded audio connectors, it is not our specialty.
• In our shop the ends of the bundle are professionally terminated and tinned to fit your specific connectors; if needed, crimped with ferrules.
• For audiophile orders we offer the Russian lead-free PSr3.5 solder with 3.5% silver (chemically Sn96.5Ag3.5, GOST 19738-74, made by Solder Chemi) or the common SAC305 with 3% silver and 0.5% copper (Sn96.5Ag3.0Cu0.5, made by IZAGRI or CYNEL) — the very solder that reviews from industry stores recommend directly for the internal wiring of loudspeakers and audio-video cables. Both solders give a dense, mechanically stable joint with low contact resistance and considerably higher conductivity than ordinary tin-lead POS-61.

The cost of the service is 500 rubles per end termination with ordinary solder, 900 rubles with silver-bearing solder, per cable end. For a standard three-meter pair of speaker cable (four ends) that is 2,000 to 3,600 rubles on top. Compared with four thousand dollars for a Cardas Clear Beyond, it is a sum not worth skimping on if you want to get everything from the cable's physics that it can deliver.

And yes, to the question "is the difference between ordinary solder and silver noticeable?" I answer honestly. Physically, in the numbers of contact impedance, there is a difference: a few milliohms per joint. In an ordinary system only a very trained ear in a very resolving chain will hear it, and even then only in a direct A/B comparison on one and the same passage. In an average home system the difference stays below the threshold of hearing. But ritual and honest physics point in the same direction here: silver solder really does conduct current at HF better than tin-lead or standard lead-free. If it matters to you to know that the whole chain from copper to connector uses the best available, this is it.

Herb Reichert wrote in one of his "Gramophone Dreams": "I gave away my expensive cables, came to a $2,000 British system, and it is enough for me." Not everyone is ready to walk his path. But everyone can at least learn that inside expensive cables there is usually a simple physical principle, and this principle is available without the store markup.

Litz wire is not magic. It is an honest engineering answer to an honest physical question about how to transmit a signal with minimal loss. The fact that it underlies both $50,000 audiophile systems and the windings of Tesla motors is no coincidence. It is the same copper, the same geometry, the same physics. The difference is that in one case it is wrapped in myth and sold to the owners of collectors' systems in $500,000 living rooms, and in the other it is handed to engineers on assembly lines at a reasonable price.

Frequently asked questions

What is litz wire in audio cables, in plain terms?

Litz wire is a high-frequency conductor made of many insulated thin copper strands, each of which, during stranding, successively occupies every position across the bundle cross-section (center and outer). This transposition equalizes the current distribution among the strands and radically suppresses the skin effect and the proximity effect across the audio and ultrasonic range. The concept was patented by Karl Ferdinand Braun in 1910, and the physics is described in hundreds of papers in IEEE Transactions on Power Electronics. This is exactly the construction found inside flagship audio cables such as Cardas Clear Beyond, Kimber Select KS-6068, Stealth Dream Petite V16 and Audio Note Lexus.

How does OFC differ from 4N copper, and is it worth paying extra for?

OFC (Oxygen-Free Copper) is copper with an oxygen content below 10 ppm. 4N means 99.99% copper (four nines). 5N and 6N are even higher purity grades. In an audio cable with a solid 2 mm² conductor, the difference between OFC and ordinary copper is minimal and usually inaudible. But there is a manufacturing subtlety: any litz wire is made from thin strands of 0.05–0.25 mm, and such strands physically cannot be drawn from recycled stock — the drawing machine tears the metal at the impurities. Therefore litz wire is automatically made from primary copper of at least OFC grade, and often 4N. There is nothing extra to pay for a "4N" label here — the purity is already built into the process.

Can litz wire be soldered at home with an ordinary iron?

Not recommended. Litz wire consists of hundreds of thin strands, each coated in enamel. An ordinary 60-watt iron does not heat the bundle evenly: on some strands the enamel remains and they are not electrically connected (the transposition is broken, and one channel sounds duller), while on others the enamel and insulation melt inside the bundle. Proper termination of class F litz wire is dipping the end of the bundle into a solder bath at 380–400 °C; for class 200 it is laser cleaning or friction stripping. This is standard equipment on a cable production floor, but impossible to reproduce in a home kitchen.

Is there an audible difference between ordinary solder and silver PSr3.5?

Physically there is a difference: the contact resistance of a joint made with silver-bearing PSr3.5 solder (Sn96.5Ag3.5) or SAC305 (Sn96.5Ag3Cu0.5) is a few milliohms lower than ordinary POS-61. Acoustically, in an ordinary system this difference stays below the threshold of hearing. Only a very trained ear in a high-resolution chain will catch it, and only in a direct A/B comparison. Silver solder is justified not by an audible difference but by engineering honesty: if you are building the whole chain from copper to connector out of the best available, this is your solder.

Why is industrial litz wire hundreds of times cheaper than Cardas Clear Beyond if the physics is the same?

Because the price of a branded audio cable is construction plus mythology plus distribution plus the retailer's margin plus marketing. The wire itself, broken down into parts, costs tens of dollars. Industrial litz wire from a cable plant is sold at the cost of materials plus production cost — on the order of a few dollars per meter. A three-meter pair of speaker cable made from Литц хА with quality Neutrik or Furutech connectors can be built for about $55–165. The physics inside is the same: transposition per Braun's principle, primary 4N copper, a low-tan-δ dielectric.