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One of the more intriguing discussions we had at last week's Consumer Electronics Show (CES) was with Jim Weil of Berkeley, CA–based Sound Application.

The company's line conditioners have been well-reviewed and have been endorsed by a number of the industry's luminaries, including engineer Tim De Paravacini and loudspeaker designers Alan Yun and Albert Von Schweikert. Mobile Fidelity's Shawn Britten uses Sound Application devices for high-resolution mastering, and CBS has them installed in its Studio Center listening room. Once dismissed by old school engineers as snake oil, AC line conditioners have become de rigueur for recording studios, mastering houses, and high-quality playback systems.

At CES, Jim engaged us with a deep-geek exploration of the AC interface, something usually overlooked by novice audiophiles. Every aspect of the design of an AC outlet, the wire that connects it to the service panel and the power grid, and the ground system that anchors it can affect the performance of audio and video systems. Jim pointed out the importance of heavy-gauge (10AWG or better) dedicated wiring to the outlets feeding your system, and said that special attention should be paid to grounding—at the very least, making sure your grounds are soldered on shiny-bright copper water pipes, or better, to individual ground rods driven into electrolytically-treated soil. He favors hollow copper pipe for grounding rather than the solid copper usually used for that purpose.

The design of an AC outlet is far more complicated than it might appear. The spacing of the receptacle contacts and the metals they are made of can have clearly audible effects. So can the polymer used to make the body of the outlet. Jim is especially disdainful of cheap nylon outlets; his Sound Application line conditioners feature top-grade Hubbell outlets, with a black nylon strike plate over an undyed phenolic body. Chemists know that colorants alter the dielectric properties of polymers, and have formulas that predict just how much they will be altered by which colors. (This may be the grain of truth in the fringe element theory that some colors of cables sound better than others.)

Weil has also extensively researched the metallurgy of electrical contacts, and claims that his not only offer the lowest practical contact resistance and the highest conductivity, but also one of the best grip strengths in the industry. The power connecting rails in Sound Application's outlets are an unusual brass alloy - 75% copper, 22% zinc, and 3% aluminum. Nickel plating sounds terrible for audio use, Weil asserts. "The only reason it's used in hospital grade outlets is for spark suppression where oxygen is in use," he explained.

He's also not a fan of the ubiquitous IEC 15 ampere connector which appears on almost all audiophile gear and aftermarket power cords, although it's used on Sound Application's XE-6 conditioner. One of my personal (and probably pointless) crusades, the IEC 15A connector was developed for low-current applications like computer printers, not for power amplifiers. Even the best ones have almost no grip strength and can be dislodged easily. Much more robust is the IEC 20A connector, used on Weil's Line Stage and XE-12S conditioners, as well as on some large power amps and the Audio Power Industries Power Wedges. Sound Application devices use point-to-point wiring throughout to improve reliability and response time. Weil says they come with an unconditional warranty.

I first became aware of the AC interface problem years ago, before audiophile-grade line conditioners were widely available. The old house I was living in at the time had outlets so worn they would barely hang onto a plug even when its prongs were spread as far apart as possible. It was particularly bad in the music room. Simply changing the outlets yielded a huge improvement in the sound of my audio system, especially in the bass. That experience launched me on a long exploration of house wiring systems and devices, and a willingness to experiment with line conditioners—AudioPrism's EFX and Foundation products and their QuietLine AC filters, the PS Audio PowerPlant P300, and most recently, the excellent SineLock devices built by former Threshold Audio president Chris English. Sound Application's devices have definitely tweaked my interest. The company is nearby, and this investigation will continue.