Miyajima Lab Wo-1 preamplifier Specifications

Sidebar 2: Specifications

Description: Two-channel, stereo, tubed preamplifier with MM phono stage. NOS vacuum tube complement: two E80F or EF86, two 6BX7, two 12AU7, two 6SN7. Inputs: Phono A, Phono B, Tuner, CD, Aux-1, Aux-2 (all RCA). Output: two pair single-ended (RCA). Input impedance: Phono A: 47k ohms; Phono B: 620, 15k, 30k, 47k, 68k, 100k ohms. Output impedance: 1.9k ohms (plate follower). Frequency range: 5Hz–70kHz (–2dB). Channel separation: 48dB. S/N ratio: 70dB. MM phono stage gain: 38dB; line stage gain: 47dB. Maximum input sensitivity: Phono 1.8mV (at 1V); Aux 21.3mV (at 1V). Power consumption: 100W.
Dimensions: 18.9" (480mm) W × 18.1" (460mm) D × 6.9" (175mm) H (including terminals). Weight 46lb (21kg).
Finish: Silver.
Serial number of revew sample: None found.
Price: $21,500. Approximate number of dealers: five. Warranty: two years.
Manufacturer: Miyajima Laboratory, 4-3-25, Chayama, Jounan-ku, Fukuoka City, Fukuoka, 814-0111, Japan. Tel: 81-92-801-6660. Email: edison@miyajima-lab.com. Web: miyajima-lab.com. US distributor: Robyatt Audio, 513 Dotters Corner Rd., Kunkletown, PA 18058. Tel: (855) 762-9288. Web: robyattaudio.com.

COMPANY INFO
Miyajima Laboratory
4-3-25, Chayama, Jounan-ku
Fukuoka City, Fukuoka, 814-0111
Japan
edison@miyajima-lab.com
81-92-801-6660
ARTICLE CONTENTS

COMMENTS
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."

Dang.

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.

X