The 47 Laboratory System by Sakura Systems

Blair Roger -- I suppose you’re going to think I’m a complete hypocrite, and I wouldn’t blame you if you did. I don’t really care. It’s only solid state – but I like it!

I’ve spent some time telling you how much I love the sound of tubes, particularly the Jadis and Bel Canto amplifiers, and now I’m going to turn around and proselytize for some solid state gear – from Japan. Yes, Japan: the little island nation that brought us Sony, Sansui, Panasonic, Yamaha, Yorx and many other fine brands of transistorized receivers that rocked us out of our adolescent bedrooms.

The Japanese knew what North American youth wanted back in the 1960s: power and lots of it. Distortion be damned. Distortion was way cool ’cause Big Bad Dad couldn’t stand it. For many of us, too young to own a car or a motorcycle, a loud, hideously gritty stereo was the ultimate form of rebellion. So BBD (as he was affectionately known) would retire to his den, light up a briar pipe and settle back to listen to his new Marantz 10B, Quad IIs and ESL-57s. Odd how we grow to respect the intelligence, tolerance, and sensitivity of our elders, as we grow older, isn’t it?

The only similarity between those execrable brands of audio equipment that figured so large in our youth, and remain forever tainted with juvenilia, and the 47 Laboratory System is the fact that they are all bereft of tubes. In the case of the 47 Lab, it’s a good thing.

System description

The entire 47 Laboratory System is the creation of Junji Kimura. He is an electronic designer and audiophile who has worked for an impressive variety of audio firms. In 1963, at the age of 23. he began with Pioneer, moving on to Kenwood, Luxman and Kyosera before founding his own company, 47 Laboratory, in 1992. This is a very unusual pattern of employment. Typical Japanese workers stay with one employer for life. However, there is nothing typical about Kimura-san or his products.

The 47 Laboratory System

The heart of the system is the Gaincard amplifier: dual mono in construction and housed in a highly rigid aluminum chassis measuring 6 ¾” x 1 ½” x 4″ (WxHxD). Front and rear panels are 0.04″ thick machined aluminum plate. Please try to visualize this positively Lilliputian stereo amplifier. It’s about the size of two decks of cigarettes. You can easily hold it in the palm of your hand and it looks indestructible. Finish is brushed black aluminum and markings are extremely understated, some so minutely engraved that you may need a magnifying glass to read them. I certainly did. Controls consist of one stepped attenuator per channel and a pair of sub-miniature mute switches. There is no on/off switch as the system is meant to be powered-up all the time.

There are only ten parts per channel including the twelve-step dual-mono attenuators. In conjunction with the electronically stiff and hefty (170 VA) Power Humpty outboard power supply, the Gaincard produces 25 class A/B Watts per channel. My bet is they’re mostly class A. Signal paths are extraordinarily short because the circuit board for each channel only measures 1 ¾” x 1 1/8″. The chassis contains no damping or potting material.

A matching selector box, called the Chooser, is available to facilitate the use of four unbalanced inputs and two pairs of unbalanced outputs. The Gaincard and Chooser are meant to be stacked one above the other and couple neatly together with three mini spiked feet. If your system is dedicated to a single analog or digital source then you really don’t need a Chooser. Add one later when you really need it.

Kimura-san thinks of everything, including interconnects and cables, as being part of the system. He has developed interconnects of such simplicity that I laughed the first time I saw them. They are called the OTA Kit and consist of 12 pairs of machined, soft plastic RCA plugs, 50 meters of 0.4mm solid core OFC copper wire and 2 mm of plastic (Teflon?) tubing for insulation. The user can make up custom length interconnects and speaker cables without any solder connections – only scissors and tweezers are required. According to the manual, the Master believes that “These are the necessary and sufficient requirements for a conductor suitable for audio cables. In other words, other characteristics do not matter.” After listening, I can’t disagree.

As my personal system is analog based, the Canadian distributor of the 47 Laboratory System supplied me with the diminutive Phono Cube and matching outboard Power Humpty. This proved to be a bit of a luxury as both the Gaincard and the Phono Cube can be powered from a single Power Humpty. On the other hand, I just learned from Yoshi Segoshi, the American distributor, that with some extra connectors I could run the left channel of the Gaincard and Phono Cube from one Humpty and the right channels of each from another Humpty for true dual mono power. Then for a digital power source, just add a third power supply, called the Power Dumpty. Well, why not? As Surrealist painter, Salvador Dali said in a television commercial about thirty years ago, “When you’ve got it, flaunt it”.

The Phono Cube, like the rest of the system is dual mono and measures only 3 ½” x 4″ x 3 ½” (WxHxD), and features standard and high gain inputs. Output is 47 Ohms and ,as I discovered, this unit is meant specifically for use with the Chooser/Gaincard. I’m not sure that anyone but Kimura-san understands exactly how this works but the input impedance of the Phono Cube is zero Ohms (yes, zero!) and I quote the manual: “(this) enables all of the current generated by the cartridge to flow directly into the amplifying circuit.” Therefore, instead of trying to step up the fractional millivolts produced by your MC cartridge (along with all the noise), the Phono Cube passes all that beautiful, pure current right through to the amplifier without any voltage dependant frequency peaks and valleys. And it works – at least with the Gaincard, I should say. My Jadis Orchestra amplifier was unable to consummate a relationship with the Phono Cube so I would venture that if you are considering the 47 Laboratory System, mixing and matching could be a questionable proposition. If you are unsure ,and just want to get your feet wet with a superb phono section, why not ask your dealer if you can try it at home with your own setup?


4706 Gaincard Amplifier (US$1250.00), 4707 Chooser (US$600.00), 4708 OTA Kit (US$500.00), Phono Cube (US$1750.00), 4700 Power Humpty (US$1500.00)

How to Listen to the 47 Laboratory System

This brings me to a crucial point. The first time I heard the 47 (as I’ll call it for brevity) in my home, I was rather unimpressed. In fact, I don’t think I really liked it. You may feel the same way and wonder what all the fuss is about. Don’t make any hasty judgements based on what you hear at the dealer’s salon. Similarly, refrain from doing so based on what you hear at home until the Gaincard has been powered up continuously for a minimum of three days. All components in the 47 system run very cool so I never worried about leaving them on all the time. I really started to like what I was hearing after about a week of break-in. This effect is very strange and somewhat difficult to explain but your patience will be rewarded. Either that or you’ll decide the 47 just doesn’t do it for you.

Something else of great significance for many readers: you will have to give up your Watt fetish. More is not better. Don’t be put off by the 47’s 25 Wpc rating. Kimura-san is just being honest with you. If he told you it was 100 Wpc, I doubt that any of you who are music lovers would question him or even care. Putting things in context, I listened to the 47 for several weeks driving my pair of Quad 63 Monitors in a room about 18′ x 25′ and rarely felt them to be out of their depth. A slightly smaller room would be perfect. Slightly more sensitive speakers might do the trick (and by that I mean they would send you to Heaven). Experiment. Get loose. Have some fun! The dynamics and frequency response of the 47 will have your friends dropping their hors d’eouvres and spilling Vodka Martinis on the Kirmin rug. Really.


I’m going to be blunt about this: the 47 has to be broken in with at least one week of continuous power-up, and if you’re looking for tube sound you’ve come to the wrong place. If you want to listen to music, then settle back and let the 47 weave its delicate spell of silken thread. Now this is ‘high definition’ audio. It is a sound that is subtly different from what I have come to know as some of the best in either camp – vacuum or solid state. It is a sound for connoisseurs: those who can appreciate the difference, let us say, between very, very good tuna sushi and Hawaiian tuna.

First came the shock of the solidity with which the 47 presents a soundstage. Before knowing anything about the Gaincard I said, “This is dual-mono, isn’t it” and laughed aloud. Then I realized that this tiny amp driving the Quad 63s is rated at only 25 Wpc and that I could hear the subways criss-crossing under Kingsway Hall very clearly on the RCA re-issue of Swan Lake from The Royal Ballet Gala (LDS 6065). I have never heard such deep, shuddering bass from Quad 63s before. And this with the 0.4 mm solid core OTA Kit speaker cables. The intoxicatingly beautiful harp solo to stage right soon proved the Gaincard’s finesse with treble transients that were quick, clear and anything but threadbare.

I have a very unusual piece composed by Mozart; Notturno for Four Orchestras K. 286 recorded by Peter Maag and the London Symphony Orchestra (STS 15088) for Decca/London. The main orchestra stretches across centre stage with the second, smaller group behind it to stage right. The third group of players is seated on the far left of the stage and the fourth orchestra is behind the second one, again on stage right. Mozart tosses the parts around between the orchestras, simulating an echo of the melody played by the first orchestra. The timbre of the strings is light and delicate and the echo effects revealed by the 47 are spellbinding.

Speaking of echo effects – my favorite test record is a bit of fluff concocted by harpist Andreas Vollenweider called Caverna Majica (CBS 37827). It’s sort of a pop-synth impressionist tone-poem fantasy about the adventures of a couple that stumbles into a magic cave. In the opening cut they discover the entrance to the cave, and as they enter the main gallery from a footpath the sound stage suddenly explodes with the synthesized echoes of their boots splashing about in a space that must be the size of an aircraft hanger. I’ve never heard it sound larger or more detailed than with the 47 Gaincard and Phono Cube. Very amusing.

Finally, for beauty of tone and depth of emotional involvement, it would be hard to beat the Adagio from Shostakovitch’s Symphony Number 7: The Leningrad from the winter of 1941 as performed by the Bournemouth Symphony under Berglund (EMI SLS 897). As the composer wrote, this movement was meant to represent “great pathos expressing ecstatic love of life and the beauties of nature.” When I listen to this piece, I am in the hall at its premiere in Leningrad. I feel I have lived my whole life for this moment. I forget myself and become one with the music.


The 47 Laboratory System cries out to be carefully matched with sympathetic ancillary components. In the relatively short time I had it available to me I grew to enjoy the sound of the Phono Cube and Gaincard very much. However, I knew that the rest of my system was not optimized to take full advantage of their subtle characteristics and capabilities. As I said previously, slightly more sensitive speakers or a slightly smaller room would be beneficial. Additionally, the prospective purchaser should select their phono cartridge with great care to avoid an overly tipped-up treble. This would be the kiss of death with solid state gear of this refinement. At the other end of the frequency spectrum, be sure your speakers don’t truncate the bottom octave or reproduce it as mellow mush. If that’s what you hear, don’t blame it on the 47.

Further information: Sakura Systems