It seems to me that a step-up transformer, at least conceptually, makes the strongest argument for being a moving-coil cartridge's ideal partner. Let's look for a moment at the required overall system gain. Assuming a low-gain MC with a nominal output of 0.2 millivolt and a power amplifier sensitivity of 2 Volt, the gain required to drive the amplifier to full power is no less than a factor of 10,000 or 80 dB. Most phono preamplifiers are designed to accommodate a MM cartridge and feature about 50 dB of gain and a 47kOhm input impedance. So we would be searching for an additional 30 dB or so of clean and low-noise gain. Well, I can't think of a more logical candidate than a transformer for these tasks. That's not to say that an active head amp or high-gain phono stage couldn't perform as well, but the catch would be a much higher price tag. That's the penalty of active amplification with its dependence on multiple gain stages, expensive passive parts, and a good power supply which is at the mercy of the AC mains. A moving-coil step-up by contrast is totally isolated from the electric grid – it is as passive as they come.
The Live! MC-10 features the Hashimoto HM-3 MC step-up transformer. Haven't heard of Hashimoto? Well, forget Tamura and Tango, the Hashimoto brand in my estimation is “best of breed.” Hashimoto Electric Co., Ltd, embodies some 60 years of transformer design and manufacturing experience. Mr. Takao Ishiguro, who is currently a technical advisor for Hashimoto due to his semi-retirement, has been the heart and soul of the Hashimoto transformer line for the past 30 years. Prior to that, he had worked at Sansui before they had transferred the transformer business to Hashimoto. Their stated goal is to produce the best sounding and highest quality audio transformers and their products have earned a stellar reputation for sonic excellence. In fact, their design philosophy focuses not just on excellence in technical measurements but seeks to capture the inherent beauty and tonal balance of live music. I'm told that Hashimoto engineers conduct serious listening tests in the context of a highly-refined reference system to evaluate new transformer designs. These designs are modified and re-tested in an iterative fashion, until they are able to reproduce the tonal balance and clarity of the real thing. As you can see, audio transformer design is more than just about science and engineering, as the folks at Hashimoto have elevated it to an art form. My recent exposure to the Air Tight ATM-1S stereo amplifier convinced me of that. The shift from Tamura to Hashimoto iron in this particular design brought me closer to the essence of the music.
The primary is split into two sections which can be connected in either parallel or series via a switch. In parallel connection the gain is x40 and the effective impedance presented to the cartridge is 3 Ohm, said to be suitable for cartridges with an internal impedance of 2 to 7 Ohm. While in series connection the gain is x20 and the effective impedance is 12 Ohms, suitable for cartridges rated from 7 to 40 Ohm. Since the cartridge has to generate the magnetizing current for the transformer, this business of matching impedances has less to do with gain and more to do with maximizing power transfer. However, don't hesitate to experiment with the load switch. One of the settings should sound best with your cartridge. The MC-10 can accommodate a wide range of moving coils, including the popular Denon DL-103 and certainly all of the cartridges I happened to have in the house.
Isao Asakura, SoundTradition's president places great importance on chassis selection and proper mounting techniques. He recognizes that when signal voltage is only a fraction of a millivolt it is prone to contamination by hum and EMI. Even slight vibrations of the hook up wires can impact the sound quality. Therefore, he had spent over a year experimenting with various chassis designs in order to optimize the performance of the HM-3 transformer. The MC-10 uses a 2-mm thick aluminum chassis which is damped to reduce vibration.
The MC-10 continued its extended stay in the reference system while I upgraded my Kuzma Stabi Reference turntable with the Kuzma 313 VTA arm, which replaced the Graham Engineering 2.5 arm. The Kuzma table/arm combo turned out fabulous and the MC-10 had no trouble facilitating a rock-solid soundstage and amazingly palpable image outlines. Fasten your seat belts! Dynamic contrasts were easily navigated as it shifted “gears” from soft to loud without even a hint of compression.
Enter the Shelter Harmony MC. I've already sung this cartridge's praises in an earlier review. Its exceptional coherence and image stability were undiluted by the MC-10. Yet again I preferred it over Shelter's own 411 Type 2 step-up for its transparency, immediacy, and greater harmonic color saturation. Tonal balance was full-bodied and wide-bandwidth. An orchestra's bass foundation was given full scope of expression. Transient attack and decay were very well controlled resulting in a lucid reproduction of hall decay. In the low-impedance setting, the sound was almost single-ended-triode like with plenty of kinetic drive, and lively mids. In particular, there was something very special about the upper mids, a pure tone that I've come to know and love. And based on my previous experience with their transformers, it would be fair to describe it as Hashimoto's calling card. Here too I preferred the low-impedance setting. In the high-impedance setting, the sound became slightly de-focused and less dimensional. Textures weren't as smooth and dynamic contrasts were not nearly as convincing either. Yet the manufacturer's recommended load impedance is 10 to 30 Ohm.
I don't want to leave the impression that the low-impedance setting was always best. It wasn't. In the case of my long-time workhorse, the Symphonic Line RG-8 Gold, a modified van den Hul Grasshopper MC, I preferred the high-impedance setting because of its enhanced dynamics although the treble was not as smooth. These findings should prove instructive on the importance of experimenting with the optimum load setting for a given cartridge. The MC-10 gives you a cartridge loading option and it is real easy to flick those switches from low to high and back again to determine which loading works best the old fashion way – by letting your ears be the final arbiter when it comes to sound quality.
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