He started his audio career in 1959 as an engineering staff at Tokyo Sound Co., engaged in the manufacture of cartridges and tonearms for professional broadcasting purposes on behalf of NHK (Japanese National Braodcast Co.), etc.
Mr. Matsudaira-san then moved on to Spex Co. in 1967, where he brushed up on his inborn talent for design during the next 10 years, specialising in design and engineering of MM/MC cartridges and tone-arms for various company clients.
In the late 70's, thanks to his outstanding capabilities, he was invited to be part of an independent development team for the masterpieces of the top-brand phono cartridges (Koetsu, Miyabi, etc.).
He joined Audio Craft Co. in 1981 as chief engineer and presented such exquisite works as the AC-3 stereo cartridge, the AC-3300/4400 tonearms, the AR-110/110L turntables, the TS-200 MC transformer, the PE-6000 Signature phono amp.
To realize his long-cherished dream, he formed his own My Sonic Lab company in 2003, and introduced the EMINENT ideal high-output, low-impedance MC cartridge and the matching MC transformer Stage 202.
With My Sonic Lab, Mr. Matsudaira-san is fulfilling his design goals of producing a moving coil cartridge with very low internal impedance. With this design, Mr. Matsudaira-san feels that the energy producing potential of an MC cartridge is fully realized.
Matsudaira-san uses an ultra high-μ material which he has named SH-μX. This material allows My Sonic Lab to significantly reduce the amount of coil wire required to give a decent output level. With the reduction in the amount of coil wire comes greater low-level resolution.
In most low-output MC cartridge designs (typically 0.1mV to 0.7mV output), a higher output like 0.3mV to 0.7mV has more coil windings inside the cartridge, which typically yields less resolution and low-level detail.
A lower output like 0.1mV to 0.25mV would have lesser coil windings, yielding better resolution and low-level detail.
This is the standard in most MC low-output MC cartridge designs. With the limitations of most of today's phono stages, however, it is easier to get more energy or liveliness in the music with a low-output MC cartridge having a gain of 0.3mV to 0.7mV, at the expense of ultimate resolution.
If one has to maximize the potential of an MC cartridge having a low output like 0.1mV to 0.25mv for example, one needs a superb high gain phono stage with enough gain and excellent noise control.
My Sonic Lab broke the barrier instead of going with the standard. From Matsudaira-san's long years of experience, he designed his low-output cartridges to have minimal coil windings for high resolution and yet have high-output gains of 0.3mV to 0.5mV output for easily unleashing music's energy during playback. An excellent balance.
Read on below ...
The ultimate target of MC cartridge is to derive "High" energy from "Low" impedance circuitry.
For this purpose, many manufacturers, small or large, so far have employed various sorts of materials and devices such as:
Selection of cantilever material
Purification of wire material
New material for housing
Polish on stylus tip
But actually for these 30 years, nothing has been noticeably improved in respect of technical data; on the contrary, something adverse has been done in the light of the above-mentioned principle "output voltage vs. internal impedance".
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, the limitations.
2 ohms at internal impedance and 0.5mV at output voltage - a bold challenge. With this in mind, we started 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, while a small output voltage yields transmission loss to the next stages including interconnects, thus inevitably deteriorating signal quality and increasing noise in components.
Nevertheless, it is mechanically and physically impossible to increment the output voltage of today's MC cartridge up to the 3mV to 5mV level due to the load amount imposed on the vibration system.
In view of the usual workable range of the step-up and head-amp devices, it was considered to be reasonable to set up the output voltage at 0.3mV to 0.5mV. How does one reduce the impedance with such output level?
The first task tackled was to design a 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 and material, and whatever material you may select, one is unable to get over the barrier unless saturation flux density is augmented.
After years of exhaustive R & D efforts, we finally developed our exclusive ultra-hi-μ core material named the SH-μX.
The SH-μX boasts of such huge saturation flux density and initial permeability exceeding 3 times more than those of conventional Hi-μ core.
The SH-μX 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 resolution throughout whole spectrum of audio bandwidth.
issue No. 37
by Jason Hector