Hi-Fi News Review Extract
Aside from my reservations about any cartridge costing more than 100 pounds, the PC-1 dazzled me for all the right reasons: silky, seductive sound, fairly easy matching, superb build quality. If you have the sort of loose change needed to acquire one, it joins a very select band. World Class? Believe it.
Ken Kessler, Hi-Fi News June 2007.

But actually for these 30 years, nothing has been noticeably improved in respect of technical data; to the contrary something adverse has been done in the light of the above-mentioned principle "output voltage vs. internal impedance".   

Certainly, compared to the samarium or cerium cobalt magnet used 30 years ago, the neodynium magnet forming today's mainstream is enhanced by as much as 3 times in terms of energy product, but it does not help augment the output voltage.  

Through our long experience, our ultimate goal was set up to clear the barriers:

2.5 ohms at internal impedance & 0.6mV at output voltage, and our bold challenge started here to work out a solution to this theme; that means, the high source impedance (resistive components of coil) causes considerable consumption of the generated energy in the inside of the coils, whilst small output voltage yields transmission loss to the next stages including interconnections, thus inevitably deteriorating signal quality and increasing noise components.  Nevertheless, it is mechanically and physically impossible to increment the output voltage of today's MC cartridge up to the 3mV - 5mV level due to load amount imposed on the vibration system.  

In view of usual workable range of the step-up and head-amp devices, it was considered to be reasonable to set up the output voltage at 0.5mV -  0.7mV.  How to reduce the impedance with such output level?  

The first task tackled was to design high-efficiency magnetic circuitry.  The reason why the high energy product inherent in today's magnet cannot be utilised lies in the magnetic saturation of the pole piece & material, and whatever material you may select, you are unable to get over the barrier unless saturation flux density is augmented.

After years' exhaustive R & D efforts, finally developed is our exclusive ultra-hi-μ core material named  the SH-μX.  This SH-μX boasting of such huge saturation flux density and initial permeability exceeding 3 times more than those of conventional Hi-u core brings forth unprecedented high-efficiency magnetic characteristics, which permits remarkable reduction in the number of coil winds, thus suppressing the inner loss down to the minimum, while its high output voltage makes it possible to reproduce an  overwhelming energy sensation and extraordinary high resolutions throughout whole spectrum of audio bandwidth.

TECHNICAL DATA

History
More than 30 years ago in my LUXMAN days, having planned the MC-115C phono cartridge and asked late Mr. Sugano the founder of the Koetsu to produce it on our behalf, but he was already quite old at that time and the product did not come out for a long time. Eventually a young engineer was one year apprenticed to him to be taught all the know-how, but the project could not show progress. Then later suddenly, to our pleasant surprise, the cartridges started to be delivered,, but it was found later that the man-behind-the-scenes named Mr. Y. Matsudaira made all the jobs. Dedicated to R & D of cartridge & phono-reproduction for more than 20 years at various firms, e.g., Tokyo Sound, Spex, Entre, etc., at that time he was already an expert/craftman with full knowledge and experience.

After long time, I happened to see him in Las Vegas, At that time he was working at Audio Craft, and I recommended him to market their products in USA & Europe, playing all the intermediary roles. In this process, I came to possess all of his products, thus knowing both of the merits and demerits, and gave him the necessary advices.

In 2004 he got independent and formed the My Sonic Lab. At that time he has already procured a special core material for cartridge. For a few decades in phono cartridge no progress has been marked:: Selection and employment of various materials have been attempted by many manufac- turers, e.g., neodynium/palladium for magnet, gold/silver of high purity for wires, and aluminium/ sapphire for cantilever, to name a few. But all are far from the "High Output & LowImpedance".,- (Difficult to solve, indeed: To obtain high output, you may increase the winding turns of coil, but this automatically increases the inner impedance as well.) After all, he introduced his own cartridge with the dream high-µ core material.

For a long time I have auditioned this cartridge, and finally consulted with him about the possible design of what yields the very sounds I've been long seeking.. To provide the dynamic sensations indispensable to reproduction of discs, I made a proposal to apply wire of a little bigger gauge with a couple more winds employing the aluminium or boron for the cantilever. The reason for this proposal is: I thought utilising his epoch-making core material an ideal design would be realised in terms of the wire material, its gauge, and the number of the winding turns, thus making it possible to achieve the ultimate target - High Output & Low Impedance. The result was much more than expected.

The antinomic theme - High Output and Low Impedance - was now solved and made compatible thanks to the extraordinary high-µ core, which makes it possible to enjoy an unparalleled sonic reproduction offering next-to-none musicality without somehow maculate or opaque feelings inherent in conventional MC cartridges and quick response to the signal source with instant attack & phase-out.

A. Miura