Miyajima Lab Wo-1 preamplifier

A phenomenon formerly unique to Japan, which in recent years has been emulated in cities around the world, is the jazz café (known as jazz kissa in Japan; footnote 1), where salarymen can find respite from their hectic lives, loosen their ties, and enjoy hi-fi jazz over coffee or a drink. Jazz kissaten are typically charming, smaller shops, traditionally furnished and paneled in beautiful wood, which serve superb artisan coffee in artful ceramic cups.

Such respect for artistry, craftsmanship, and attention to detail—the Japanese word is shokunin—is reflected in many aspects of Japanese life. This is where you find double handrails to accommodate people of different heights, intricate, ornately designed manhole covers, and bento lunch boxes with hand-carved vegetable figurines. While upholding strict conformity to societal norms, the Japanese highly value creative individualism. This shokunin mindset underlies their reverence for artisanal expression—and their love for jazz.

Japanese audio, much like jazz kissaten, reflects the shokunin mindset: craftsmanship pursued with both pride and humility. Consequently, tube amplifiers from established Japanese brands—AirTight, Kondo, Leben, Luxman, Shindo, Yamamoto—have been held in high esteem for decades. Manufacturers less well-known in the West—Audio Tekne, Spec, Triode Labs, and Takatsuki/Alex Sound—are just as well-respected. Japanese cartridges, too—from brands such as Audio Technica, Denon, Hana/Etsuro Urushi, Ikeda Labs, Koetsu, Miyabi Labs, Nagaoka, Shelter Audio, and Sumiko—are widely revered.

Tube technology found favor in the 1950s among such Japanese advocates of low-power amplification as Kei Ikeda and Nobu Shishido of Wavac. They in turn inspired Jean Hiraga, a French-Japanese engineer and editor of L'Audiophile, who wrote the 1990 book Initiation aux Amplis à Tubes (Introduction to Tube Amps). Hiraga was "the first guy in the Western world to promote low-power amps and high-efficiency speakers," Joe Roberts, former editor of the influential magazine Sound Practices, told me in an interview (footnote 2). "The presence and influence of esoteric Japanese phono technology, from the '80s until now, is evidenced in the enduring popularity of Micro Seiki, Fidelity Research, and Grace, to name a few. Miyajima is in the tradition of taking things a step further."

The shop
Miyajima Laboratory was founded on March 27, 1980, by Noriyuki Miyajima, initially as an audio store. The company operates out of a small, three-story building in the ancient port city of Fukuoka in the south of Japan, employing six people.

Miyajima's objective, their "Profile" webpage states, is to "advance the design and production of the finest-sounding analog audio components"; the company's core philosophy is to "skillfully build superior audio components that will reproduce recorded sound so faithfully, that the artists' personality and the emotions in their music are perfectly expressed." Miyajima's first product was a 6B4G mono amplifier. Not long after, a series of stereo cartridges was released—the Takumi, Saboten, Carbon, Shilabe, Kansui, Madake, and Destiny—garnering global acclaim and consistently listing in Class A of Stereophile's Recommended Components list.

In addition to cartridges, Miyajima currently produces four step-up transformers (SUTs), two headphone amplifiers, a pair of large, open-baffle loudspeakers, the Model 2020 OTL power amplifier (footnote 3), and two preamplifiers: the EC-5 and the Wo-1, which is the subject of this review.

"Unique hand-made Japanese artisanal"
The $21,500 Wo-1 (short for "World-1") stands 6.9" tall, 18.9" wide, and 18.1" deep and weighs 46.3lb. Its front and back panels are made of aluminum, as are its control knobs. The sides, top, and bottom sections are steel. Two sturdy steel handles are mounted on each side of the front panel, so repositioning the preamp is a breeze. Knob indices and other markings are engraved on the faceplate, including—with obvious pride—the words heading this section.

The Wo-1 is built to battleship-worthy standards. The tubes, chokes, capacitors, and transformers are all affixed to a massive steel plate with point-to-point, Miyajima-made copper wiring below. Four pairs of tubes power the Wo-1: a pair of globe-bottle Psvane 6SN7 SE tubes and a pair of NOS Telefunken 12AU7 tubes (both pairs controlling line-level signal), two NOS Sylvania 6XB7GT tubes (output), and a pair of NOS Heath/Mullard E80F tubes (in the phono stage). A large SEL power transformer, four SEL chokes, and 10 large CDE capacitors are arrayed to the right of the tubes.

In operation, the Wo-1 is simplicity itself. On the left are a glass current meter and associated controls, which enable biasing of the 6SN7 tubes; on the right are input and mode (channel and gain) selectors and volume and power knobs. The no-nonsense back panel includes an IEC jack and a fuse holder, two pairs of output jacks (RCA), and five pairs of input jacks (RCA).

In a Google Translate–mediated email exchange with Noriyuki Miyajima, I asked about the volume control. Miyajima explained that in the Wo-1, "no audio signal passes through the resistors. I wanted to avoid using the commonly used volume resistors. It's a low impedance and high voltage design which gives a very dynamic and powerful presentation. I want a powerful, roaring sound."

US distributor Robin Wyatt, of Robyatt Audio, elaborated. "It's a gain-tracking device, not a potentiometer or attenuator. As you turn the volume knob, it changes the incoming gain via a tube circuit. You set the input gain feeding the amp [and adjust it] at any point ... as needed, with no volume pot in the circuit."

The Wo-1's handles made hauling it around my listening crib and sliding it into my Salamander rack a cinch. I used Thorens and VPI turntables with a variety of MC cartridges wired into Tavish Audio, Manley Labs, and Pathos phono stages. I compared the Wo-1 to Sugden and Shindo Allegro preamplifiers and a Mytek Brooklyn with preamp features. I used Shindo Haut-Brion and Mytek Brooklyn power amplifiers to drive Volti Audio Razz and Harbeth Super HL5plus XD loudspeakers. AudioQuest, Analysis Plus, Triode Wire Labs, and Shindo cabling carried audio messages. Robin Wyatt biased the amp upon arrival. After that, I didn't touch the bias settings.

From experience, I learned to spin the gain knob back and forth with the power off. When I didn't, the preamp emitted loud, unfriendly pops on startup and whenever I increased the gain. Silicone spray didn't help, but my daily rotation ritual did.

Footnote 1: Jazz Kissa 2014 and a sequel titled Jazz Kissa 2015–2019, from Japanese publisher Jazz City, present a photographic essay of nearly 200 of these much-loved establishments from across Japan.

Footnote 2: More about Jean Hiraga can be found in Keith Howard's article "Euphonic Distortion: Naughty but Nice?" from April 2006.

Footnote 3: Model 2020's predecessor, model 2010, was reviewed by Art Dudley in July 2014.

Miyajima Laboratory
4-3-25, Chayama, Jounan-ku
Fukuoka City, Fukuoka, 814-0111

Ortofan's picture

... falling on his sword.

How does an ill-performing, if not outright defective, product such as this one ever get released to market?
Is this a typical example of "unique hand-made artisanal" electronics?

With $21,500 to spend on a tube-type preamp, I'd be heading to a McIntosh dealer to buy a C2700 - and with the money leftover, an MC1502 tube-type power amp.

Glotz's picture

Very disrespectful.

When's your preamp coming out?

Ortofan's picture

... the output acceptable to you?

This product should have stayed in the "laboratory".

It reminds me of an incident related by a member in a speaker manufacturer's forum in which a tube-type preamp had failed by generating a significant DC voltage at the output. The preamp was connected to a DC-coupled solid-state power amplifier, which amplified the faulty DC signal from the preamp and sent it to the speakers, thereby burning out the woofers. The cost of the replacement drivers was several thousand dollars. The speaker manufacturer would not cover the cost under warranty since it was due to the faulty preamp. The preamp manufacturer's warranty only covered the cost to fix the preamp. After it was repaired, the owner traded-in the preamp for a solid-state model and traded-in the power amp for one that was not DC-coupled.

Glotz's picture

Wow, you really have a complete, selfless dedication to consumer affairs, especially across the entire internet.

To the designer, not so much. This issue you speak of to his design is not the same mfg. you elucidate above, correct?

Your circuit point is valid, yet your methods of communication not so much. The way you go about your points are consistently disrespectful & repulsive (esp. for someone who hasn't tread upon you personally).

Caveat emptor. The stuff lawsuits are made of, esp. for well-heeled audiophiles.

Ortofan's picture

... all of the time.

First, JVS objected to the use of hyperbole.
Then, someone else objected to the use of metaphor.
Who's next to be offended by the use of a literary device?

Glotz's picture

This goes well beyond a literally device for someone Japanese.

I get it: your disgust and indignance needs to have a snappy literary device for extra effect. Internal snickers and all that.

rwwear's picture

Wouldn't that be a conflict of interest?

Glotz's picture

It was said facetiously. His criticisms were not unfounded, but the method of delivering them was...

Nirodha352's picture

Or Zanden which should have been included in this review for several reasons

Kursun's picture

It is a good practice to switch on the preamplifier first, then the power amplifier. But this is too much!
One false move and your loudspeakers are fried!
I wonder why they at least didn't put a delay circuit at its output.

I would also have preferred to see hermetically sealed micro relays as input selectors. The classical mechanical input switch would oxidise and wear out in a few years and start emitting annoying noises.

kai's picture

There‘s no general rule that relays have superior longevity to mechanical switches.

A well capsuled an greased switch can last forever.
On the other hand I’ve seen loads of failing relays during my career.

When the switch that controls the relay fails, the whole thing doesn’t work any more.

Kursun's picture

Well before the switch completely fails, it starts its noisy operation and keeps like that for years.Since it is on the signal path you'll hear its every stage of degeneration.

Absolute longevity is not the most important factor.
Signal passing without any degeneration is.
An old mechanical switch contacts may even act as diodes.

Mikke's picture

... the primary objective is "Primum non nocere".This is the physician's duty to first and foremost to avoid harming the patient during the treatment.
I did not know that such an objective should be relevant in the audio business. Apparently it is.
I think I´ll stay true to my trusty solid state preamp.

Lars Bo's picture

Thanks, Ken.

The Miyajima Wo-1 is, to me, one of the most interesting preamps out there, and it has been high on my "SP-review wanted list" for years (personally, I only have a full experience with two Miyajima cartridges and a SUT).

Your quote of Miyajima's goal - i.e. to convey musical sound so faithfully that the personality and emotions of the artists are perfectly expressed - seems to be in tune with a distinction between an instrumental and a terminal goal of the "inventor" of High Fidelity, engineer H.A. Hartley. In 1958, he wrote:

"I invented the phrase "high fidelity" in 1927 to denote a type of sound reproduction that might be taken rather seriously by a music lover. In those days the average radio or phonograph equipment sounded pretty horrible but, as I was really interested in music, it occurred to me that something might be done about it."*

In contrast, many a modern definition of high fidelity doesn't include the concept of music and/or musical(ity) whatsoever. Hartley's vision, however, almost a century ago, was to bring the essence of a musical experience home, by, though not exclusively, applying science and technique in sound reproduction. The terminal goal of high fidelity was to convey the "it" that drives humankind to music in the first place. Hartley elaborates, on a fact and a consequential primacy (as he saw it... but, hey):

"Perfect reproduction of an original performance in an auditorium cannot be achieved in the home. The esthetically equipped expert can only strive to provide a standard which is musically satisfying. This phrase is introduced deliberately, because, when science has done its best, the ear itself is the final arbiter and, when the engineer has done as well as his technique will allow, he must then apply the principles of musical criticism to what he has accomplished."**

Noriyuki Miyajima certainly appears to expertly apply such principles well in the mix.

Thanks again.

*H.A. Hartley's Audio Design Handbook (1958 Gernsback Library), p. 200
**ibid., p. 21

ken mac's picture

for your comment.

Nirodha352's picture

“ and an occasional sheen that revealed the amplifier's class-D heart.‘ please stop trying to give class D amps some high-end validity

rwwear's picture

Sounds like the handles may be the best thing about it?

Ortofan's picture

... tend to resonate, with an adverse effect on sound quality, so they should be removed once the unit is installed.

rwwear's picture

.....Remove the faceplate and knobs, etc....

Anton's picture

"....With a modern direct-coupled solid state amplifier, that initial DC offset will destroy the loudspeakers' woofers."


I'm not kvetching about the sonics or the price, just the risk!

directdriver's picture

According to their website, the preamp's output does not use a cathode follower. Instead it uses a "plate follower" or anode follower which renders it higher output impedance, as shown in the measurements, than typical cathode follower circuits.