My 80% nickel-core EMIA MC Step-Up Transformer ($2700 with copper wire, $4800 with silver wire, footnote 2) was designed and wound by Dave Slagle specifically for Koetsu cartridges. With my Rosewood Signature Platinum, it sounds delicious and plays butter-smooth. I cherish it for its unfettered ease and completeness. The EMIA SUT makes the Platinum sound dense and radiant in a natural "not-hi-fi" way. For example, this combo reproduces Todd Garfinkle's magnificent recording Será una Noche (MA Recordings LP MA062A-V) in such a subtle-but-brilliant manner that it encourages me to believe I am wandering the Argentinian grasslands in a surreal cinematic dream. That's how Koetsu cartridges work driving high-nickel SUTs. In my experience, nickel delivers tone and emotion in gobs while putting an attractive, burnished radiance around plucked, bowed, picked, and hammered string tones.
So, reader be warned: I come to this month's story about new-school transformer core materials biased in favor of old-school core materials.
Amorphous Core (Lundahl)
K&K Audio's $1500 Premium Silver MC Step-Up (footnote 3) uses Lundahl's LL1931 Ag transformers, which are made with Lundahl's "finest amorphous cobalt uncut strip core" and wound with pure silver wire. According to K&K Audio's Kevin Carter, "The LL1931 provides a very open and detailed picture of the 'space' that was recorded, providing a level of detail recovery that I had never previously experienced with LPs."
My auditions confirmed Kevin's observation, but my experience with this transformer is limited, because I auditioned it with only one cartridge: the high-impedance (40 ohm) Zu Audio Zu/DL-103 Mk.II moving coil. (Lundahl's website specifically recommends the LL1931 Ag's step-up ratio for use with 40 ohm cartridges. )
I listened to the K&K + Zu-Denon (with a variety of RIAA stages) over many months. Every record testified to the mesmerizing effects of the LL1931's clarity and the goose-bumpiness of its transient bite. Bass reproduction could be thrilling, just-right tight with genuine power. The LL1931's best, most obvious trait was how specifically it rendered recorded information. Its worst trait was that, compared to Auditorium 23's mu-metal SUT (which was designed by Keith Aschenbrenner for use with the DL-103), it made the spaces between details feel empty, causing reverb tails and vibrating cathedral air to go missing or attenuated. The Lundahl transformers (footnote 4) showcased tight bass, intense detail, and a somewhat blunt clarity. The A23 showcased tone-truthfulness, rhythmic bounce, and a more refined presentation of ambience.
According to Per Lundahl, writing by email, "Choice of core material is a question of taste. Our top-of-the-line MC transformers are available with either our uncut amorphous strip core (like the LL1931) or with a conventional mu-metal lamination core (like the LL1933). As it has turned out, the amorphous-core transformer is most popular, but the mu-metal lamination transformer is still preferred by some audiophiles. In THD ... and linearity measurements, the mu-metal lamination version outperforms the amorphous core version, but in listening tests, the amorphous core usually wins."
I asked Per to explain the metallurgical differences between mu-metal, amorphous cobalt, and nanocrystalline transformer cores.
"In true amorphous material, there should not be any crystal structure. Atoms are randomly oriented, and there is no repeated structure such as you find in most solid metals. To achieve this, the melted metal is cooled so rapidly that atoms get stuck in their random positions. ... This very rapid cooling requirement is the reason why amorphous metal is only available as thin film, about 1 mil (0.025 mm) thick.
"To achieve nanocrystalline material, special amorphous iron is carefully heat treated at very controlled temperatures. In this process, very small [nano]crystals are formed."
Nano Crystal Core (Sculpture A)
My old Triodefest Eurobuddy François Saint-Gérand is the founder of Sculpture A (footnote 5) as well as Cala Mighty Sound and Ana Mighty Sound. All three companies traffic in exotic analog devices, most especially moving coil cartridges based on Denon's venerable DL-103 with various degrees of hot-rodding. According to Francois, "Sculpture A is a regrouping of different talents including Laszlo Szalai, who builds our cartridges, Zsolt Bodnar, who designs our step-ups, and Terry Hamlyn, who makes the industrial design for our cartridges."
As long as I've known Francçis, he has been ears-deep in his own brand of cartridge studies. My past auditions of Cala and Ana Mighty Sound cartridges suggest that he is an experienced listener with sophisticated taste who, similar to me, likes sound that is big, fast, lush, and super-3D, which is exactly what Sculpture A's $1955 A.3L moving coil cartridge sounds like with its matching $950 Mini Nano SUT.
The A.3L cartridge is a stripped-down Denon DL-103 that retains only the original cartridge's iron magnet and pole piece. It replaces its aluminum cantilever and spherical stylus with a boron cantilever and a nude line-contact stylus. The Denon's horrid plastic body is replaced by an expensive-looking body made from bronze and wood.
After his review in Analog Corner #309, Michael Fremer sent me these Sculpture A products for a second opinion. He thought they should be auditioned in the company of more modestly priced components than his $250,000 record player and $50k phono stage.
What I heard, with my not-free Dr. Feickert Blackbird turntable sitting on a Kuzma Platis 65 turntable platform with my 10.5" Thomas Schick tonearm and the bargain-of-the-century Tavish Design Adagio phono stage, was a cartridge that excavated myriad details and dense textures but ran a bit dark and wet. Maybe not "wet kiss from my least favorite aunt" wet (like Mikey said) but misty-drizzle wet.
One night during my Sculpture A auditions, I dreamed that the reason cartridges sound different is energy storage. I saw an orchestra of vibrating parts deliberately storing and releasing energy at vastly different tempos. The next day, I imagined it was the A.3L's bronze-and-wood body that was making that wet sound.
So I replaced the Sculpture A cartridge with Zu Audio's aluminum-bodied Denon: the $499 Zu DL-103 Mk.II. And guess what? The sun came out and scintillating transients returned.
Sculpture A's Mini Nano SUT was my first in-house experience with a nanocrystal-core transformer. If they all sound anything like this $950 Mini Nano, a lot of phonophiles will be getting revved by how big, reverberant, and overtly spatial they make recordings sound. With the Mini Nano tied to the Zu–DL-103, image size jumped up at least 20% compared to the Auditorium 23 SUT. Brightness and raw presence increased also, as did the intensity of reverb on Miles Davis recordings.
As I listened, I wondered: Is this nanocrystal adding something to the sound? Or is it recovering information that has been subtracted by other core technologies? There's no way I can know, but I agree with Per Lundahl, "Choice of core material is a question of taste."
Mystery Core (Koetsu)
After all my explanations about trending, newfangled transformer core technologies, I find it interesting that Koetsu (footnote 6) offers no information about the technology that goes into its newest step-up transformer—no mention of core material, core shape, or winding-wire. I can't be prebiased about this SUT, because all I know about it is that it's made to mate with Koetsu cartridges, has 26dB gain, a 20Hz–50kHz (±3dB) bandwidth, comes in a nondescript, 2lb, 5.51" × 2.83" × 6.10" steel box with stick-on rubber feet, and costs $4995. What exactly is in the box? I sent an email to designer Fumihiko Sugano, but he hasn't written back yet, so I don't know. And I don't care.
I don't care because, when I connected it up to my $8495 Koetsu Rosewood Signature Platinum cartridge and played the MoFi reissue of Miles Davis's In a Silent Way (MFSL-1-377), the reverb was dramatically more intense. I repeat, dramatically more intense, with more force behind it than I normally experience using my EMIA SUT or any other transformer. The sound from my Gold Badge Falcon speakers pressurized my room with unprecedented vigor. That's $13,490 worth of cartridge and dedicated step-up transformer, and I don't care about the price or what it is made of. I don't care because Herbie Hancock's notes were bigger, more I-am-there real, more tangibly architectural than they ever were before. It made Teo Macero's artfully rendered sound collage into an electrifying wonderment.
As I was listening, the Koetsu transformer's overt thrillingness struck me as a denser, more powerful, more focused version of the nanocrystal excitements I experienced with the Sculpture A Mini Nano. This new Koetsu SUT did not sound like plain old copper wire wound on a generic mu-metal or amorphous core. And which metals it might be made of does not matter at all, because a) it matches the Koetsu cartridge perfectly and b) it makes recordings into a continuous stream of Wow! moments. Maybe it's wow metal?
Addendum
I turned in this report at 6:27pm on August 10. At 11:34pm that night, I received a response to my core-material question from Sugano-san via a translator organized by Jon Derda at MoFi. Among other comments, he wrote this: "[T]he magnetic characteristics of the permalloy, the core material of [the] Koetsu SUT, is easily affected by external shock and vibration." So, it's permalloy: The same material used in the cores of the EMIA SUT. To prevent external shock and vibration, the Koetsu transformer "floats" the core inside the aluminum housing using an antivibration material. The Koetsu transformers shield electromagnetic interference by wrapping each transformer in both copper foil (to shield electric fields) and more permalloy (to shield magnetic fields).
Footnote 2: EMIA, Web: myemia.com. E-mail: info@myemia.com. Footnote 3: K&K Audio, 579 Tanager Ln., Chapel Hill, NC 27517. Tel: (919) 869-7547. Web: kandkaudio.com. Footnote 4: Lundahl, Tibeliusgatan 7, 761 50 Norrtälje, Tel: +46 176 13930. Web: lundahltransformers.com Footnote 5: Sculpture A, 75020 Paris, France. Web: sculpture-a.com. Authorized US resellers: Artisan Fidelity, Tel: (219) 933-8115, Web: artisanfidelity.com. Sonare Coeli, Tel: (715) 4124139. Chris Sommovigo, Web: stereolab.shop.
Footnote 6: Koetsu. Web: koetsuaudio.com. US distributor: MoFi Distribution. Web: mofidistribution.com.
So, reader be warned: I come to this month's story about new-school transformer core materials biased in favor of old-school core materials.
Amorphous Core (Lundahl)K&K Audio's $1500 Premium Silver MC Step-Up (footnote 3) uses Lundahl's LL1931 Ag transformers, which are made with Lundahl's "finest amorphous cobalt uncut strip core" and wound with pure silver wire. According to K&K Audio's Kevin Carter, "The LL1931 provides a very open and detailed picture of the 'space' that was recorded, providing a level of detail recovery that I had never previously experienced with LPs."
My old Triodefest Eurobuddy François Saint-Gérand is the founder of Sculpture A (footnote 5) as well as Cala Mighty Sound and Ana Mighty Sound. All three companies traffic in exotic analog devices, most especially moving coil cartridges based on Denon's venerable DL-103 with various degrees of hot-rodding. According to Francois, "Sculpture A is a regrouping of different talents including Laszlo Szalai, who builds our cartridges, Zsolt Bodnar, who designs our step-ups, and Terry Hamlyn, who makes the industrial design for our cartridges."
As long as I've known Francçis, he has been ears-deep in his own brand of cartridge studies. My past auditions of Cala and Ana Mighty Sound cartridges suggest that he is an experienced listener with sophisticated taste who, similar to me, likes sound that is big, fast, lush, and super-3D, which is exactly what Sculpture A's $1955 A.3L moving coil cartridge sounds like with its matching $950 Mini Nano SUT.
The A.3L cartridge is a stripped-down Denon DL-103 that retains only the original cartridge's iron magnet and pole piece. It replaces its aluminum cantilever and spherical stylus with a boron cantilever and a nude line-contact stylus. The Denon's horrid plastic body is replaced by an expensive-looking body made from bronze and wood.
After all my explanations about trending, newfangled transformer core technologies, I find it interesting that Koetsu (footnote 6) offers no information about the technology that goes into its newest step-up transformer—no mention of core material, core shape, or winding-wire. I can't be prebiased about this SUT, because all I know about it is that it's made to mate with Koetsu cartridges, has 26dB gain, a 20Hz–50kHz (±3dB) bandwidth, comes in a nondescript, 2lb, 5.51" × 2.83" × 6.10" steel box with stick-on rubber feet, and costs $4995. What exactly is in the box? I sent an email to designer Fumihiko Sugano, but he hasn't written back yet, so I don't know. And I don't care.
I don't care because, when I connected it up to my $8495 Koetsu Rosewood Signature Platinum cartridge and played the MoFi reissue of Miles Davis's In a Silent Way (MFSL-1-377), the reverb was dramatically more intense. I repeat, dramatically more intense, with more force behind it than I normally experience using my EMIA SUT or any other transformer. The sound from my Gold Badge Falcon speakers pressurized my room with unprecedented vigor. That's $13,490 worth of cartridge and dedicated step-up transformer, and I don't care about the price or what it is made of. I don't care because Herbie Hancock's notes were bigger, more I-am-there real, more tangibly architectural than they ever were before. It made Teo Macero's artfully rendered sound collage into an electrifying wonderment.
As I was listening, the Koetsu transformer's overt thrillingness struck me as a denser, more powerful, more focused version of the nanocrystal excitements I experienced with the Sculpture A Mini Nano. This new Koetsu SUT did not sound like plain old copper wire wound on a generic mu-metal or amorphous core. And which metals it might be made of does not matter at all, because a) it matches the Koetsu cartridge perfectly and b) it makes recordings into a continuous stream of Wow! moments. Maybe it's wow metal?
I turned in this report at 6:27pm on August 10. At 11:34pm that night, I received a response to my core-material question from Sugano-san via a translator organized by Jon Derda at MoFi. Among other comments, he wrote this: "[T]he magnetic characteristics of the permalloy, the core material of [the] Koetsu SUT, is easily affected by external shock and vibration." So, it's permalloy: The same material used in the cores of the EMIA SUT. To prevent external shock and vibration, the Koetsu transformer "floats" the core inside the aluminum housing using an antivibration material. The Koetsu transformers shield electromagnetic interference by wrapping each transformer in both copper foil (to shield electric fields) and more permalloy (to shield magnetic fields).
Footnote 2: EMIA, Web: myemia.com. E-mail: info@myemia.com. Footnote 3: K&K Audio, 579 Tanager Ln., Chapel Hill, NC 27517. Tel: (919) 869-7547. Web: kandkaudio.com. Footnote 4: Lundahl, Tibeliusgatan 7, 761 50 Norrtälje, Tel: +46 176 13930. Web: lundahltransformers.com Footnote 5: Sculpture A, 75020 Paris, France. Web: sculpture-a.com. Authorized US resellers: Artisan Fidelity, Tel: (219) 933-8115, Web: artisanfidelity.com. Sonare Coeli, Tel: (715) 4124139. Chris Sommovigo, Web: stereolab.shop.
