TESTED: Running Springs Audio Dmitri AC Power Conditioner

No Tradeoffs

AC power-conditioning specialist Running Springs Audio has quietly established itself in many first-rate retailers and upper-end systems over the past eight years. Although it has not received as much attention as some others in the category, the company behind Running Springs Audio has long been a pillar of the high end. There’s a good chance that some of the capacitors, transformers, or inductors in your preamplifier, power amplifier, phonostage, AC conditioner, or digital source were made by RTI Electronics, the parent company of Running Springs Audio. In addition to manufacturing transformers and inductors, RTI makes the Teflon, Mylar, metalized polypropylene, and oil capacitors found in some extremely prestigious components.

Running Springs Audio was established to bring finished products to the market, specifically AC-power-conditioning devices. The company enjoys several advantages by virtue of its association with the large parent electronics-manufacturing company. First, RSA has the resources to develop proprietary capacitor and inductor designs specifically for audio-system power conditioning. More than 90% of the parts inside the RSA conditioners are made in house. Second, RSA has access to a highly advanced technical laboratory that’s focused on capacitor and inductor development and testing. Third, the assemblers building RSA conditioners routinely work on electronics that go into NASA, military, and medical applications; the factory is ISO 9001:2000 certified. Fourth, building the components in house allows RSA tighter control over component quality. Finally, RSA claims that in-house component-manufacturing allows it to use a quality of parts that would be prohibitive in other similarly priced products.

The company makes five AC conditioners ranging from the $1699 1800W Haley to the ten-outlet, 2400W, $4499 Dmitri reviewed here. (The conditioners are named after musicians—Jaco and Duke for examples. I presume the Dimitri is named for Shostakovich.) Each of the Dmitri’s outlets is individually isolated from the others, and all are identical—there are no “amplifier” or “digital” blocks of outlets. All the products in the line feature the same parts quality, including platinum-foil capacitors hand-trimmed to achieve 1% tolerances. They also share a proprietary inductor developed specifically for audio-system AC conditioning. This inductor features a special synthetic matrix, around which the coil is hand-wound. This synthetic compound reportedly provides better performance than iron- or air-core inductors. The internal wiring is Cardas. Incidentally, the conditioners work with 110V or 220V AC power without reconfiguring.

The Dmitri is available with a stock AC cord (20-amp connector) for $4495; the Dmitri and a Running Springs Audio Mongoose AC cord are $4999; the top-of-the-line HZ (for “High-Zoot”) cord bumps the price to $5999. The Mongoose is made by Cardas to RSA’s spec; the HZ is designed and built by RSA. The conditioners are sold by forty-five U.S. retailers and on four continents. The company plans to introduce a line of interconnects and loudspeaker cable at the Rocky Mountain Audio Fest this October.

The Dmitri is an extremely solid product; lifting it feels like lifting a solid block of metal (it weighs 67 pounds). In fact, the chassis is non-ferrous, and the front panel is pure carbon-fiber. Additional carbon-fiber inside the unit damps vibration. The unit has no switches, lights, or adjustments (except a rear-panel circuit breaker).

Listening

Over the past fifteen years AC conditioners have gone from marginal accessories to essential components of an audio system. During that time we’ve seen a wide range of designs and capabilities. As much as AC conditioning has improved the sound of audio systems on an overall basis, most of them exact some sonic tradeoffs. The typical conditioner renders a blacker background, increased transparency, cleaner timbres, and greater dimensionality, but often at the expense of compressed dynamics. The sound becomes more polite and refined, but less viscerally and emotionally involving. The better conditioners provide the traditional benefits of AC conditioning without the dynamic constriction.

The Dmitri is unique in my experience in that it not only doesn’t compress dynamics, but actually expands them. I heard this with the Dmitri powering just my front-end components, with the power amplifiers plugged into the wall outlets. (The equipment racks are at the back of the room connected to power amplifiers at the front of the room next to the loudspeakers, making it impossible to hear the entire system powered from the Dmitri.) Nonetheless, the Dmitri noticeably expanded dynamic scale and increased the sense of bottom-end heft and impact. Kick drum had more weight, body, and slam, and orchestral climaxes were more powerful. In addition to these sonically identifiable changes, music just seemed to have greater rhythmic coherence and flow with the Dmitri.